,,discourses3                           
,,biological  ,,geological              
,,essays                                
,,by                                    
,,thomas ,h4 ,,huxley                   
#ahid        ,,preface      ,the        
contents of the present volume1 with    
three exceptions1 are either  popular   
lectures1 or addresses delivered to     
scientific bodies with which  ,i have   
been officially connected4 ,i am not    
sure which gave me the more  trouble4   
,for ,i have not been one of those      
fortunate persons who are able  to      
regard a popular lecture as a mere hors 
d'oeuvre1 unworthy of being  ranked     
among the serious efforts of a          
philosopher2 and who keep their  fame as
 scientific hierophants unsullied by    
attempts--at least of the  successful   
sort--to be understanded of the people4 
,on the contrary1 ,i found that the task
 of putting the truths learned in  the  
field1 the laboratory and the museum1   
into language which1 without  bating a  

jot of scientific accuracy shall be     
generally intelligible1  taxed such     
scientific and literary faculty as ,i   
possessed to the  uttermost2 indeed my  
experience has furnished me with no     
better  corrective of the tendency to   
scholastic pedantry which besets all    
those  who are absorbed in pursuits     
remote from the common ways of men1 and 
become habituated to think and speak in 
the technical dialect of their  own     
little world1 as if there were no other4
    ,if the popular lecture thus1 as ,i 
believe1 finds one moiety of its        
justification in the self-discipline of 
the lecturer1 it surely finds the  other
 half in its effect on the auditory4    
,for though various sadly  comical      
experiences of the results of my own    
efforts have led me to  entertain a very
 moderate estimate of the purely        
intellectual value of  lectures2 though 
,i venture to doubt if more than one in 
ten of an average  audience carries away
 an accurate notion of what the speaker 

has been  driving at2 yet is that not   
equally true of the oratory of the      
hustings1  of the ,house of ,commons1   
and even of the pulpit8    ,yet the     
children of this world are wise in their
 generation2 and both the  politician   
and the priest are justified by results4
 ,the living voice has  an influence    
over human action altogether independent
 of the intellectual  worth of that     
which it utters4 ,many years ago1 ,i was
 a guest at a great  ,city dinner4 ,a   
famous orator1 endowed with a voice of  
rare flexibility  and power2 a born     
actor1 ranging with ease through every  
part1 from  refined comedy to tragic    
unction1 was called upon to reply to a  
toast4  ,the orator was a very busy man1
 a charming conversationalist and by no 
means despised a good dinner2 and1 ,i   
imagine1 rose without having given a    
thought to what he was going to say4    
,the rhythmic roll of sound was         
admirable1 the gestures perfect1 the    
earnestness impressive2 nothing was     

lacking save sense and1 occasionally1   
grammar4 ,when the speaker sat down  the
 applause was terrific and one of my    
neighbours was especially  enthusiastic4
 ,so when he had quieted down1 ,i asked 
him what the orator  had said4 ,and he  
could not tell me4    ,that sagacious   
person ,john ,wesley1 is reported to    
have replied to some  one who questioned
 the propriety of his adaptation of     
sacred words to  extremely secular airs1
 that he did not see why the ,devil     
should be left  in possession of all the
 best tunes4 ,and ,i do not see why     
science should  not turn to account the 
peculiarities of human nature thus      
exploited by  other agencies3 all the   
more because science1 by the nature of  
its being1  cannot desire to stir the   
passions1 or profit by the weaknesses1  
of human  nature4 ,the most zealous of  
popular lecturers can aim at nothing    
more  than the awakening of a sympathy  
for abstract truth1 in those who do not 
really follow his arguments2 and of a   

desire to know more and better in  the  
few who do4    ,at the same time it must
 be admitted that the popularization of 
science1  whether by lecture or essay1  
has its drawbacks4 ,success in this     
department has its perils for those who 
succeed4 ,the people who fail  take     
their revenge1 as we have recently had  
occasion to observe1 by  ignoring all   
the rest of a man's work and glibly     
labelling him a more  popularizer4 ,if  
the falsehood were not too glaring1 they
 would say the  same of ,faraday and    
,helmholtz and ,kelvin4    ,on the other
 hand1 of the affliction caused by      
persons who think that  what they have  
picked up from popular exposition       
qualifies them for  discussing the great
 problems of science1 it may be said1 as
 the ,radical  toast said of the power  
of the ,crown in bygone days1 that it   
has  increased1 is increasing1 and ought
 to be diminished4 ,the oddities of     
,english as she is spoke might be       
abundantly paralleled by those of       

,science as she is misunderstood in the 
sermon1 the novel1 and the  leading     
article2 and a collection of the        
grotesque travesties of  scientific     
conceptions1 in the shape of essays on  
such trifles as the  ,nature of ,life   
and the ,origin of ,all ,things1 which  
reach me1 from time  to time1 might well
 be bound up with them4      ,the tenth 
essay in this volume unfortunately      
brought me1 ,i will not say  into       
collision1 but into a position of       
critical remonstrance with regard  to   
some charges of physical heterodoxy1    
brought by my distinguished  friend     
,lord ,kelvin1 against ,british         
,geology4 ,as ,president of the         
,geological ,society of ,london at that 
time 7#ahfi71 ,i thought ,i might       
venture to plead that we were not such  
heretics as we seemed to be2 and  that1 
even if we were1 recantation would not  
affect the question of  evolution4    ,i
 am glad to see that ,lord ,kelvin has  
just reprinted his reply to my  plea1#a 

and ,i refer the reader to it4 ,i shall 
not presume to question  anything1 that 
on such ripe consideration1 ,lord       
,kelvin has to say upon  the physical   
problems involved4 ,but ,i may remark   
that no one can have  asserted more     
strongly than ,i have done1 the         
necessity of looking to  physics and    
mathematics1 for help in regard to the  
earliest history of  the globe4 7,see   
pp4 #ajh and #aji of this volume47      
,footnote #a3 ,popular ,lectures and    
,addresses4 ,,ii4 ,macmillan and ,co4   
#ahid4    ,and ,i take the opportunity  
of repeating the opinion1 that1 whether 
what  we call geological time has the   
lower limit assigned to it by ,lord     
,kelvin1 or the higher assumed by other 
philosophers2 whether the germs of  all 
living things have originated in the    
globe itself1 or whether they  have been
 imported on1 or in1 meteorites from    
without1 the problem of the  origin of  
those successive ,faunae and ,florae of 
the earth1 the existence of  which is   

fully demonstrated by paleontology      
remains exactly where it was4    ,for ,i
 think it will be admitted1 that the    
germs brought to us by  meteorites1 if  
any1 were not ova of elephants1 nor of  
crocodiles2 not  cocoa-nuts nor acorns2 
not even eggs of shell-fish and corals2 
but only  those of the lowest forms of  
animal and vegetable life4 ,therefore1  
since  it is proved that1 from a very   
remote epoch of geological time1 the    
earth  has been peopled by a continual  
succession of the higher forms of       
animals  and plants1 these either must  
have been created1 or they have arisen  
by  evolution4 ,and in respect of       
certain groups of animals1 the well-    
established facts of paleontology leave 
no rational doubt that they arose  by   
the latter method4    ,in the second    
place1 there are no data whatever1 which
 justify the  biologist in assigning    
any1 even approximately definite1 period
 of time1  either long or short1 to the 
evolution of one species from another by

 the  process of variation and          
selection4 ,in the ninth of the         
following essays1  ,i have taken pains  
to prove that the change of animals has 
gone on at  very different rates in     
different groups of living beings2 that 
some  types have persisted with little  
change from the paleozoic epoch till    
now1 while others have changed rapidly  
within the limits of an epoch4 ,in      
#ahfb 7see below p4 #cjc1 #cjd7 in #ahfc
 7vol4 ,,ii41 p4 #dfa7 and again in     
#ahfd  7ibid41 p4 #hi-ia7 ,i argued1 not
 as a matter of speculation1 but1 from  
paleontological facts1 the bearing of   
which ,i believe1 up to that time1  had 
not been shown1 that any adequate       
hypothesis of the causes of  evolution  
must be consistent with progression1    
stationariness and  retrogression1 of   
the same type at different epochs2 of   
different types  in the same epoch2 and 
that ,darwin's hypothesis fulfilled     
these  conditions4    ,according to that
 hypothesis1 two factors are at work1   

variation and  selection4 ,next to      
nothing is known of the causes of the   
former process2  nothing whatever of the
 time required for the production of a  
certain  amount of deviation from the   
existing type4 ,and1 as respects        
selection1  which operates by           
extinguishing all but a small minority  
of variations1  we have not the         
slightest means of estimating the       
rapidity with which it  does its work4  
,all that we are justified in saying is 
that the rate at  which it takes place  
may vary almost indefinitely4 ,if the   
famous paint-  root of ,florida1 which  
kills white pigs but not black ones1    
were abundant  and certain in its       
action1 black pigs might be substituted 
for white in  the course of two or three
 years4 ,if1 on the other hand1 it was  
rare and  uncertain in action1 the white
 pigs might linger on for centuries4    
,t4,h4 ,,huxley4    ,,hodeslea1         
,,eastbourne1    ,april1 #ahid4         
,,contents      ,i    ,,on ,a ,,piece   

,,of ,,chalk #ahfh  7,a ,lecture        
delivered to the working men of ,norwich
 during the meeting of  the ,british    
,association47      ,,ii    ,,the       
,,problems ,,of ,,the ,,deep ,,sea #ahgh
      ,,iii    ,,on ,,some ,,of ,,the   
,,results ,,of ,,the ,,expedition ,,of  
,h4,m4,s4 ,,challenger #ahge      ,,iv  
,,yeast #ahga      ,v    ,,on ,,the     
,,formation ,,of ,,coal #ahgj  7,a      
,lecture delivered at the ,philosophical
 ,institute1 ,bradford47      ,,vi      
,,on ,,the ,,border ,,territory         
,,between ,,the ,,animal ,,and ,,the    
,,vegetable ,,kingdoms  #ahgf  7,a      
,friday evening ,lecture delivered at   
the ,royal ,institution47      ,,vii    
,a ,,lobster2 ,,or1 ,,the ,,study ,,of  
,,zoology #ahfa  7,a ,lecture delivered 
at the ,south ,kensington ,museum47     
,,viii    ,,biogenesis ,,and            
,,abiogenesis #ahgj  7,the ,presidential
 ,address to the ,meeting of the        
,british ,association for  the          
,advancement of ,science at ,liverpool47

      ,,ix    ,,geological              
,,contemporaneity ,,and ,,persistent    
,,types ,,of ,,life #ahfb  7,address to 
the ,geological ,society on behalf of   
the ,president by one of  the           
,secretaries47      ,x    ,,geological  
,,reform #ahfi  7,presidential ,address 
to the ,geological ,society47      ,,xi 
,,palaeontology ,,and ,,the ,,doctrine  
,,of ,,evolution #ahgj  7,presidential  
,address to the ,geological ,society47  
,i      ,,on ,a ,,piece ,,of ,,chalk    
#ahfh    ,if a well were sunk at our    
feet in the midst of the city of        
,norwich1 the  diggers would very soon  
find themselves at work in that white   
substance  almost too soft to be called 
rock1 with which we are all familiar as 
chalk4    ,not only here1 but over the  
whole county of ,norfolk1 the           
well-sinker  might carry his shaft down 
many hundred feet without coming to the 
end of  the chalk2 and1 on the          
sea-coast1 where the waves have pared   
away the  face of the land which breasts

 them1 the scarped faces of the high    
cliffs  are often wholly formed of the  
same material4 ,northward1 the chalk may
 be  followed as far as ,yorkshire2 on  
the south coast it appears abruptly in  
the picturesque western bays of ,dorset1
 and breaks into the ,needles of  the   
,isle of ,wight2 while on the shores of 
,kent it supplies that long line  of    
white cliffs to which ,england owes her 
name of ,albion4    ,were the thin soil 
which covers it all washed away1 a      
curved band of  white chalk1 here       
broader1 and there narrower1 might be   
followed  diagonally across ,england    
from ,lulworth in ,dorset1 to           
,flamborough ,head in  ,yorkshire--a    
distance of over #bhj miles as the crow 
flies4 ,from this band  to the ,north   
,sea1 on the east1 and the ,channel1 on 
the south1 the chalk  is largely hidden 
by other deposits2 but1 except in the   
,weald of ,kent and  ,sussex1 it enters 
into the very foundation of all the     
south-eastern  counties4    ,attaining1 

as it does in some places1 a thickness  
of more than a thousand  feet1 the      
,english chalk must be admitted to be a 
mass of considerable  magnitude4        
,nevertheless1 it covers but an         
insignificant portion of the  whole area
 occupied by the chalk formation of the 
globe1 much of which  has the same      
general characters as ours1 and is found
 in detached  patches1 some less1 and   
others more extensive1 than the         
,english4 ,chalk  occurs in north-west  
,ireland2 it stretches over a large part
 of ,france1--  the chalk which         
underlies ,paris being1 in fact1 a      
continuation of that of  the ,london    
basin2 it runs through ,denmark and     
,central ,europe1 and extends  southward
 to ,north ,africa2 while eastward1 it  
appears in the ,crimea and  in ,syria1  
and may be traced as far as the shores  
of the ,sea of ,aral1 in  ,central      
,asia4 ,if all the points at which true 
chalk occurs were  circumscribed1 they  
would lie within an irregular oval about

 #c1jjj miles  in long diameter--the    
area of which would be as great as that 
of ,europe1  and would many times exceed
 that of the largest existing inland    
sea--the  ,mediterranean4    ,thus the  
chalk is no unimportant element in the  
masonry of the earth's  crust1 and it   
impresses a peculiar stamp1 varying with
 the conditions to  which it is exposed1
 on the scenery of the districts in     
which it occurs4  ,the undulating downs 
and rounded coombs1 covered with        
sweet-grassed turf1  of our inland chalk
 country1 have a peacefully domestic and
 mutton-  suggesting prettiness1 but can
 hardly be called either grand or       
beautiful4 ,but on our southern coasts1 
the wall-sided cliffs1 many  hundred    
feet high1 with vast needles and        
pinnacles standing out in the  sea1     
sharp and solitary enough to serve as   
perches for the wary  cormorant1 confer 
a wonderful beauty and grandeur upon the
 chalk  headlands4 ,and1 in the ,east1  
chalk has its share in the formation of 

some  of the most venerable of mountain 
ranges1 such as the ,lebanon4    ,what  
is this wide-spread component of the    
surface of the earth8 and  whence did it
 come8      ,you may think this no very 
hopeful inquiry4 ,you may not           
unnaturally  suppose that the attempt to
 solve such problems as these can lead  
to no  result1 save that of entangling  
the inquirer in vague speculations1     
incapable of refutation and of          
verification4 ,if such were really the  
case1 ,i should have selected some other
 subject than a piece of chalk  for my  
discourse4 ,but1 in truth1 after much   
deliberation1 ,i have been  unable to   
think of any topic which would so well  
enable me to lead you to  see how solid 
is the foundation upon which some of the
 most startling  conclusions of physical
 science rest4    ,a great chapter of   
the history of the world is written in  
the chalk4 ,few  passages in the history
 of man can be supported by such an     
overwhelming  mass of direct and        

indirect evidence as that which         
testifies to the truth  of the fragment 
of the history of the globe1 which ,i   
hope to enable you  to read1 with your  
own eyes1 to-night4 ,let me add1 that   
few chapters of  human history have a   
more profound significance for          
ourselves4 ,i weigh my  words well when 
,i assert1 that the man who should know 
the true history  of the bit of chalk   
which every carpenter carries about in  
his breeches-  pocket1 though ignorant  
of all other history1 is likely1 if he  
will think  his knowledge out to its    
ultimate results1 to have a truer1 and  
therefore  a better1 conception of this 
wonderful universe1 and of man's        
relation to  it1 than the most learned  
student who is deep-read in the records 
of  humanity and ignorant of those of   
,nature4    ,the language of the chalk  
is not hard to learn1 not nearly so hard
 as  ,latin1 if you only want to get at 
the broad features of the story it has  
to tell2 and ,i propose that we now set 

to work to spell that story out         
together4    ,we all know that if we    
burn chalk the result is quicklime4     
,chalk1 in  fact1 is a compound of      
carbonic acid gas1 and lime1 and when   
you make it  very hot the carbonic acid 
flies away and the lime is left4 ,by    
this  method of procedure we see the    
lime1 but we do not see the carbonic    
acid4  ,if1 on the other hand1 you were 
to powder a little chalk and drop it    
into  a good deal of strong vinegar1    
there would be a great bubbling and     
fizzing1 and1 finally1 a clear liquid1  
in which no sign of chalk would  appear4
 ,here you see the carbonic acid in the 
bubbles2 the lime1  dissolved in the    
vinegar1 vanishes from sight4 ,there are
 a great many  other ways of showing    
that chalk is essentially nothing but   
carbonic acid  and quicklime4 ,chemists 
enunciate the result of all the         
experiments which  prove this1 by       
stating that chalk is almost wholly     
composed of carbonate  of lime4    ,it  

is desirable for us to start from the   
knowledge of this fact1 though  it may  
not seem to help us very far towards    
what we seek4 ,for carbonate  of lime is
 a widely-spread substance1 and is met  
with under very various  conditions4    
,all sorts of limestones are composed of
 more or less pure  carbonate of lime4  
,the crust which is often deposited by  
waters which  have drained through      
limestone rocks1 in the form of what are
 called  stalagmites and stalactites1 is
 carbonate of lime4 ,or1 to take a more 
familiar example1 the fur on the inside 
of a tea-kettle is carbonate of  lime2  
and1 for anything chemistry tells us to 
the contrary1 the chalk  might be a kind
 of gigantic fur upon the bottom of the 
earth-kettle1  which is kept pretty hot 
below4    ,let us try another method of 
making the chalk tell us its own        
history4 ,to  the unassisted eye chalk  
looks simply like a very loose and open 
kind of  stone4 ,but it is possible to  
grind a slice of chalk down so thin that

 you  can see through it--until it is   
thin enough1 in fact1 to be examined    
with  any magnifying power that may be  
thought desirable4 ,a thin slice of the 
fur of a kettle might be made in the    
same way4 ,if it were examined          
microscopically1 it would show itself to
 be a more or less distinctly  laminated
 mineral substance1 and nothing more4   
,but the slice of chalk presents a      
totally different appearance when       
placed under the microscope4 ,the       
general mass of it is made up of very   
minute granules2 but1 imbedded in this  
matrix1 are innumerable bodies1  some   
smaller and some larger1 but1 on a rough
 average1 not more than a  hundredth of 
an inch in diameter1 having a           
well-defined shape and  structure4 ,a   
cubic inch of some specimens of chalk   
may contain hundreds  of thousands of   
these bodies1 compacted together with   
incalculable  millions of the granules4 
,the examination of a transparent slice 
gives a good notion of the manner  in   

which the components of the chalk are   
arranged1 and of their relative         
proportions4 ,but1 by rubbing up some   
chalk with a brush in water and then    
pouring off the milky fluid1 so as to   
obtain sediments of different  degrees  
of fineness1 the granules and the minute
 rounded bodies may be  pretty well     
separated from one another1 and         
submitted to microscopic  examination1  
either as opaque or as transparent      
objects4 ,by combining the  views       
obtained in these various methods1 each 
of the rounded bodies may  be proved to 
be a beautifully-constructed calcareous 
fabric1 made up of a  number of         
chambers1 communicating freely with one 
another4 ,the chambered  bodies are of  
various forms4 ,one of the commonest is 
something like a  badly-grown raspberry1
 being formed of a number of nearly     
globular  chambers of different sizes   
congregated together4 ,it is called     
,globigerina1 and some specimens of     
chalk consist of little else than       

,globigerinoe and granules4 ,let us fix 
our attention upon the  ,globigerina4   
,it is the spoor of the game we are     
tracking4 ,if we can  learn what it is  
and what are the conditions of its      
existence1 we shall  see our way to the 
origin and past history of the chalk4   
,a suggestion which may naturally enough
 present itself is1 that these  curious 
bodies are the result of some process of
 aggregation which has  taken place in  
the carbonate of lime2 that1 just as in 
winter1 the rime  on our windows        
simulates the most delicate and         
elegantly arborescent  foliage--proving 
that the mere mineral water may1 under  
certain  conditions1 assume the outward 
form of organic bodies--so this mineral 
substance1 carbonate of lime1 hidden    
away in the bowels of the earth1 has    
taken the shape of these chambered      
bodies4 ,i am not raising a merely      
fanciful and unreal objection4 ,very    
learned men1 in former days1 have  even 
entertained the notion that all the     

formed things found in rocks are  of    
this nature2 and if no such conception  
is at present held to be  admissible1 it
 is because long and varied experience  
has now shown that  mineral matter never
 does assume the form and structure we  
find in  fossils4 ,if any one were to   
try to persuade you that an oyster-shell
  7which is also chiefly composed of    
carbonate of lime7 had crystallized  out
 of sea-water1 ,i suppose you would     
laugh at the absurdity4 ,your  laughter 
would be justified by the fact that all 
experience tends to show  that          
oyster-shells are formed by the agency  
of oysters1 and in no other  way4 ,and  
if there were no better reasons1 we     
should be justified1 on like  grounds1  
in believing that ,globigerina is not   
the product of anything  but vital      
activity4    ,happily1 however1 better  
evidence in proof of the organic nature 
of the  ,globigerinoe than that of      
analogy is forthcoming4 ,it so happens  
that  calcareous skeletons1 exactly     

similar to the ,globigerinoe of the     
chalk1  are being formed1 at the present
 moment1 by minute living creatures1    
which flourish in multitudes1 literally 
more numerous than the sands of  the    
sea-shore1 over a large extent of that  
part of the earth's surface  which is   
covered by the ocean4    ,the history of
 the discovery of these living          
,globigerinoe1 and of the  part which   
they play in rock building1 is singular 
enough4 ,it is a  discovery which1 like 
others of no less scientific importance1
 has  arisen1 incidentally1 out of work 
devoted to very different and           
exceedingly practical interests4 ,when  
men first took to the sea1 they         
speedily learned to look out for shoals 
and rocks2 and the more the  burthen of 
their ships increased1 the more         
imperatively necessary it  became for   
sailors to ascertain with precision the 
depth of the waters  they traversed4    
,out of this necessity grew the use of  
the lead and  sounding line2 and1       

ultimately1 marine-surveying1 which is  
the recording  of the form of coasts and
 of the depth of the sea1 as ascertained
 by the  sounding-lead1 upon charts4    
,at the same time1 it became desirable  
to ascertain and to indicate the  nature
 of the sea-bottom1 since this          
circumstance greatly affects its        
goodness as holding ground for anchors4 
,some ingenious tar1 whose name         
deserves a better fate than the oblivion
 into which it has fallen1  attained    
this object by arming the bottom of the 
lead with a lump of  grease1 to which   
more or less of the sand or mud1 or     
broken shells1 as  the case might be1   
adhered1 and was brought to the surface4
 ,but1 however  well adapted such an    
apparatus might be for rough nautical   
purposes1  scientific accuracy could not
 be expected from the armed lead1 and to
  remedy its defects 7especially when   
applied to sounding in great depths7    
,lieut4 ,brooke1 of the ,american ,navy1
 some years ago invented a most         

ingenious machine1 by which a           
considerable portion of the superficial 
layer of the sea-bottom can be scooped  
out and brought up from any depth  to   
which the lead descends4 ,in #ahec1     
,lieut4 ,brooke obtained mud from the   
bottom of the ,north ,atlantic1 between 
,newfoundland and the ,azores1 at a     
depth of more than #aj1jjj feet1 or two 
miles1 by the help of this  sounding    
apparatus4 ,the specimens were sent for 
examination to ,ehrenberg  of ,berlin1  
and to ,bailey of ,west ,point1 and     
those able microscopists  found that    
this deep-sea mud was almost entirely   
composed of the  skeletons of living    
organisms--the greater proportion of    
these being just  like the ,globigerinoe
 already known to occur in the chalk4   
,thus far1 the work had been carried on 
simply in the interests of  science1 but
 ,lieut4 ,brooke's method of sounding   
acquired a high  commercial value1 when 
the enterprise of laying down the       
telegraph-cable  between this country   

and the ,united ,states was undertaken4 
,for it became  a matter of immense     
importance to know1 not only the depth  
of the sea  over the whole line along   
which the cable was to be laid1 but the 
exact  nature of the bottom1 so as to   
guard against chances of cutting or     
fraying the strands of that costly rope4
 ,the ,admiralty consequently  ordered  
,captain ,dayman1 an old friend and     
shipmate of mine1 to ascertain  the     
depth over the whole line of the cable1 
and to bring back specimens  of the     
bottom4 ,in former days1 such a command 
as this might have sounded  very much   
like one of the impossible things which 
the young ,prince in the  ,fairy ,tales 
is ordered to do before he can obtain   
the hand of the  ,princess4 ,however1 in
 the months of ,june and ,july1 #aheg1  
my friend  performed the task assigned  
to him with great expedition and        
precision1  without1 so far as ,i know1 
having met with any reward of that kind4
 ,the  specimens or ,atlantic mud which 

he procured were sent to me to be       
examined and reported upon4#a           
,footnote #a3 ,see ,appendix to ,captain
 ,dayman's ,deep-sea ,soundings in the  
,north ,atlantic ,ocean between ,ireland
 and ,newfoundland1 made in ,h4,m4,s4   
,cyclops4 ,published by order of the    
,lords ,commissioners of the            
,admiralty1 #aheh4 ,they have since     
formed the subject of an elaborate      
,memoir by ,messrs4 ,parker and ,jones1 
published in the ,philosophical         
,transactions for #ahfe4    ,the result 
of all these operations is1 that we know
 the contours and the  nature of the    
surface-soil covered by the ,north      
,atlantic for a distance  of #a1gjj     
miles from east to west1 as well as we  
know that of any part of  the dry land4 
,it is a prodigious plain--one of the   
widest and most even  plains in the     
world4 ,if the sea were drained off1 you
 might drive a  waggon all the way from 
,valentia1 on the west coast of         
,ireland1 to  ,trinity ,bay1 in         

,newfoundland4 ,and1 except upon one    
sharp incline about  #bjj miles from    
,valentia1 ,i am not quite sure that it 
would even be  necessary to put the skid
 on1 so gentle are the ascents and      
descents upon  that long route4 ,from   
,valentia the road would lie down-hill  
for about #bjj  miles to the point at   
which the bottom is now covered by      
#a1gjj fathoms of  sea-water4 ,then     
would come the central plain1 more than 
a thousand miles  wide1 the inequalities
 of the surface of which would be hardly
  perceptible1 though the depth of water
 upon it now varies from #aj1jjj to     
#ae1jjj feet2 and there are places in   
which ,mont ,blanc might be sunk        
without showing its peak above water4   
,beyond this1 the ascent on the         
,american side commences1 and gradually 
leads1 for about #cjj miles1 to the     
,newfoundland shore4    ,almost the     
whole of the bottom of this central     
plain 7which extends for  many hundred  
miles in a north and south direction7 is

 covered by a fine  mud1 which1 when    
brought to the surface1 dries into a    
greyish white  friable substance4 ,you  
can write with this on a blackboard1 if 
you are so  inclined2 and1 to the eye1  
it is quite like very soft1 grayish     
chalk4  ,examined chemically1 it proves 
to be composed almost wholly of         
carbonate  of lime2 and if you make a   
section of it1 in the same way as that  
of the  piece of chalk was made1 and    
view it with the microscope1 it presents
  innumerable ,globigerinoe embedded in 
a granular matrix4 ,thus this deep-  sea
 mud is substantially chalk4 ,i say     
substantially1 because there are a  good
 many minor differences2 but as these   
have no bearing on the question         
immediately before us1--which is the    
nature of the ,globigerinoe of the      
chalk1--it is unnecessary to speak of   
them4    ,globigerinoe of every size1   
from the smallest to the largest1 are   
associated together in the ,atlantic    
mud1 and the chambers of many are       

filled by a soft animal matter4 ,this   
soft substance is1 in fact1 the  remains
 of the creature to which the           
,globigerinoe shell1 or rather          
skeleton1 owes its existence--and which 
is an animal of the simplest  imaginable
 description4 ,it is1 in fact1 a mere   
particle of living jelly1  without      
defined parts of any kind--without a    
mouth1 nerves1 muscles1 or  distinct    
organs1 and only manifesting its        
vitality to ordinary  observation by    
thrusting out and retracting from all   
parts of its  surface1 long filamentous 
processes1 which serve for arms and     
legs4 ,yet  this amorphous particle1    
devoid of everything which1 in the      
higher  animals1 we call organs1 is     
capable of feeding1 growing1 and        
multiplying2  of separating from the    
ocean the small proportion of carbonate 
of lime  which is dissolved in          
sea-water2 and of building up that      
substance into a  skeleton for itself1  
according to a pattern which can be     

imitated by no  other known agency4     
,the notion that animals can live and   
flourish in the sea1 at the vast  depths
 from which apparently living           
,globigerinoe2 have been brought up1    
does not agree very well with our usual 
conceptions respecting the  conditions  
of animal life2 and it is not so        
absolutely impossible as it  might at   
first sight appear to be1 that the      
,globigcrinoe of the  ,atlantic         
sea-bottom do not live and die where    
they are found4    ,as ,i have          
mentioned1 the soundings from the great 
,atlantic plain are  almost entirely    
made up of ,globigerinoe1 with the      
granules which have  been mentioned1 and
 some few other calcareous shells2 but a
 small  percentage of the chalky        
mud--perhaps at most some five per cent4
 of it--  is of a different nature1 and 
consists of shells and skeletons        
composed  of silex1 or pure flint4      
,these silicious bodies belong partly to
 the  lowly vegetable organisms which   

are called ,diatomaceoe1 and partly to  
the minute1 and extremely simple1       
animals1 termed ,radiolaria4 ,it is     
quite certain that these creatures do   
not live at the bottom of the  ocean1   
but at its surface--where they may be   
obtained in prodigious  numbers by the  
use of a properly constructed net4      
,hence it follows that  these silicious 
organisms1 though they are not heavier  
than the lightest  dust1 must have      
fallen1 in some cases1 through fifteen  
thousand feet of  water1 before they    
reached their final resting-place on the
 ocean floor4  ,and considering how     
large a surface these bodies expose in  
proportion to  their weight1 it is      
probable that they occupy a great length
 of time in  making their burial journey
 from the surface of the ,atlantic to   
the  bottom4    ,but if the ,radiolaria 
and ,diatoms are thus rained upon the   
bottom of  the sea1 from the superficial
 layer of its waters in which they pass 
their lives1 it is obviously possible   

that the ,globigerinoe may be  similarly
 derived2 and if they were so1 it would 
be much more easy to  understand how    
they obtain their supply of food than it
 is at present4  ,nevertheless1 the     
positive and negative evidence all      
points the other  way4 ,the skeletons of
 the full-grown1 deep-sea ,globigerinoe 
are so  remarkably solid and heavy in   
proportion to their surface as to seem  
little fitted for floating2 and1 as a   
matter of fact1 they are not to be      
found along with the ,diatoms and       
,radiolaria in the uppermost stratum of 
the open ocean4 ,it has been observed1  
again1 that the abundance of            
,globigerinoe1 in proportion to other   
organisms1 of like kind1 increases  with
 the depth of the sea2 and that         
deep-water ,globigerinoe are larger     
than those which live in shallower parts
 of the sea2 and such facts  negative   
the supposition that these organisms    
have been swept by currents  from the   
shallows into the deeps of the          

,atlantic4 ,it therefore seems to  be   
hardly doubtful that these wonderful    
creatures live and die at the  depths in
 which they are found4#b    ,footnote   
#b3 ,during the cruise of ,h4,m4,s4     
,bulldog1 commanded by ,sir  ,leopold   
,m',clintock1 in #ahfj1 living star-fish
 were brought up1 clinging  to the      
lowest part of the sounding-line1 from a
 depth of #a1bfj fathoms1  midway       
between ,cape ,farewell1 in ,greenland1 
and the ,rockall banks4 ,dr4  ,wallich  
ascertained that the sea-bottom at this 
point consisted of the  ordinary        
,globigerina ooze1 and that the stomachs
 of the star-fishes  were full of       
,globigerinoe4 ,this discovery removes  
all objections to the  existence of     
living ,globigerinoe at great depths1   
which are based upon  the supposed      
difficulty of maintaining animal life   
under such conditions2  and it throws   
the burden of proof upon those who      
object to the  supposition that the     
,globigerinoe live and die where they   

are found4    ,however1 the important   
points for us are1 that the living      
,globigerinoe  are exclusively marine   
animals1 the skeletons of which abound  
at the  bottom of deep seas2 and that   
there is not a shadow of reason for     
believing that the habits of the        
,globigerinoe of the chalk differed     
from those of the existing species4 ,but
 if this be true1 there is no  escaping 
the conclusion that the chalk itself is 
the dried mud of an  ancient deep sea4  
,in working over the soundings collected
 by ,captain ,dayman1 ,i was  surprised 
to find that many of what ,i have called
 the granules of that  mud were not1 as 
one might have been tempted to think at 
first1 the more  powder and waste of    
,globigerinoe1 but that they had a      
definite form and  size4 ,i termed these
 bodies coccoliths1 and doubted their   
organic  nature4 ,dr4 ,wallich verified 
my observation1 and added the           
interesting  discovery that1 not        
unfrequently1 bodies similar to these   

coccoliths  were aggregated together    
into spheroids1 which lie termed        
coccospheres4 ,so far as we knew1 these 
bodies1 the nature of which is          
extremely puzzling and problematical1   
were peculiar to the ,atlantic          
soundings4 ,but1 a few years ago1 ,mr4  
,sorby1 in making a careful  examination
 of the chalk by means of thin sections 
and otherwise1  observed1 as ,ehrenberg 
had done before him1 that much of its   
granular  basis possesses a definite    
form4 ,comparing these formed particles 
with  those in the ,atlantic soundings1 
he found the two to be identical2 and   
thus proved that the chalk1 like the    
surroundings1 contains these  mysterious
 coccoliths and coccospheres4 ,here was 
a further and most  interesting         
confirmation1 from internal evidence1 of
 the essential  identity of the chalk   
with modern deep-sea mud4 ,globigerinoe1
  coccoliths1 and coccospheres are found
 as the chief constituents of both1  and
 testify to the general similarity of   

the conditions under which both  have   
been formed4#c    ,footnote #c3 ,i have 
recently traced out the development of  
the  coccoliths from a diameter of      
#a_/gjjjth of an inch up to their       
largest  size 7which is about           
#a_/ajjjth71 and no longer doubt that   
they are  produced by independent       
organisms1 which1 like the              
,globigerinoe1 live  and die at the     
bottom of the sea4    ,the evidence     
furnished by the hewing1 facing1 and    
superposition of the  stones of the     
,pyramids1 that these structures were   
built by men1 has no  greater weight    
than the evidence that the chalk was    
built by  ,globigerinoe2 and the belief 
that those ancient pyramid-builders were
  terrestrial and air-breathing         
creatures like ourselves1 is not better 
based than the conviction that the      
chalk-makers lived in the sea4 ,but as  
our belief in the building of the       
,pyramids by men is not only grounded on
  the internal evidence afforded by     

these structures1 but gathers strength  
from multitudinous collateral proofs1   
and is clinched by the total  absence of
 any reason for a contrary belief2 so   
the evidence drawn from  the            
,globigerinoe that the chalk is an      
ancient sea-bottom1 is fortified  by    
innumerable independent lines of        
evidence2 and our belief in the truth   
of the conclusion to which all positive 
testimony tends1 receives the  like     
negative justification from the fact    
that no other hypothesis has a  shadow  
of foundation4    ,it may be worth while
 briefly to consider a few of these     
collateral  proofs that the chalk was   
deposited at the bottom of the sea4 ,the
 great  mass of the chalk is composed1  
as we have seen1 of the skeletons of    
,globigerinoe1 and other simple         
organisms1 imbedded in granular matter4 
,here and there1 however1 this hardened 
mud of the ancient sea reveals the      
remains of higher animals which have    
lived and died1 and left their hard     

parts in the mud1 just as the oysters   
die and leave their shells behind  them1
 in the mud of the present seas4        
,there are1 at the present day1 certain 
groups of animals which are never  found
 in fresh waters1 being unable to live  
anywhere but in the sea4 ,such  are the 
corals2 those corallines which are      
called ,polyzoa2 those  creatures which 
fabricate the lamp-shells1 and are      
called ,brachiopoda2  the pearly        
,nautilus1 and all animals allied to it2
 and all the forms of  sea-urchins and  
star-fishes4 ,not only are all these    
creatures confined to  salt water at the
 present day2 but1 so far as our records
 of the past go1  the conditions of     
their existence have been the same3     
hence1 their  occurrence in any deposit 
is as strong evidence as can be         
obtained1 that  that deposit was formed 
in the sea4 ,now the remains of animals 
of all the  kinds which have been       
enumerated1 occur in the chalk1 in      
greater or less  abundance2 while not   

one of those forms of shell-fish which  
are  characteristic of fresh water has  
yet been observed in it4    ,when we    
consider that the remains of more than  
three thousand distinct  species of     
aquatic animals have been discovered    
among the fossils of the  chalk1 that   
the great majority of them are of such  
forms as are now met  with only in the  
sea1 and that there is no reason to     
believe that any one  of them inhabited 
fresh water--the collateral evidence    
that the chalk  represents an ancient   
sea-bottom acquires as great force as   
the proof  derived from the nature of   
the chalk itself4 ,i think you will now 
allow  that ,i did not overstate my case
 when ,i asserted that we have as strong
  grounds for believing that all the    
vast area of dry land1 at present       
occupied by the chalk1 was once at the  
bottom of the sea1 as we have for  any  
matter of history whatever2 while there 
is no justification for any  other      
belief4    ,no less certain it is that  

the time during which the countries we  
now  call south-east ,england1 ,france1 
,germany1 ,poland1 ,russia1 ,egypt1     
,arabia1  ,syria1 were more or less     
completely covered by a deep sea1 was of
  considerable duration4 ,we have       
already seen that the chalk is1 in      
places1  more than a thousand feet      
thick4 ,i think you will agree with me1 
that it  must have taken some time for  
the skeletons of animalcules of a       
hundredth  of an inch in diameter to    
heap up such a mass as that4 ,i have    
said that  throughout the thickness of  
the chalk the remains of other animals  
are  scattered4 ,these remains are often
 in the most exquisite state of         
preservation4 ,the valves of the        
shell-fishes are commonly adherent2 the 
long spines of some of the sea-urchins1 
which would be detached by the  smallest
 jar1 often remain in their places4 ,in 
a word1 it is certain that  these       
animals have lived and died when the    
place which they now occupy  was the    

surface of as much of the chalk as had  
then been deposited2 and  that each has 
been covered up by the layer of         
,globigerina mud1 upon  which the       
creatures imbedded a little higher up   
have1 in like manner1  lived and died4  
,but some of these remains prove the    
existence of reptiles  of vast size in  
the chalk sea4 ,these lived their time1 
and had their  ancestors and            
descendants1 which assuredly implies    
time1 reptiles being  of slow growth4   
,there is more curious evidence1 again1 
that the process of covering up1  or1 in
 other words1 the deposit of            
,globigerina skeletons1 did not go on   
very fast4 ,it is demonstrable that an  
animal of the cretaceous sea might  die1
 that its skeleton might lie uncovered  
upon the sea-bottom long  enough to lose
 all its outward coverings and          
appendages by putrefaction2  and that1  
after this had happened1 another animal 
might attach itself to  the dead and    
naked skeleton1 might grow to maturity1 

and might itself die  before the        
calcareous mud had buried the whole4    
,cases of this kind are admirably       
described by ,sir ,charles ,lyell4 ,he  
speaks of the frequency with which      
geologists find in the chalk a          
fossilized sea-urchin1 to which is      
attached the lower valve of a  ,crania4 
,this is a kind of shell-fish1 with a   
shell composed of two  pieces1 of which1
 as in the oyster1 one is fixed and the 
other free4    ,the upper valve is      
almost invariably wanting1 though       
occasionally found  in a perfect state  
of preservation in the white chalk at   
some distance4  ,in this case1 we see   
clearly that the sea-urchin first lived 
from youth  to age1 then died and lost  
its spines1 which were carried away4    
,then the  young ,crania adhered to the 
bared shell1 grew and perished in its   
turn2  after which1 the upper valve was 
separated from the lower1 before the    
,echinus became enveloped in chalky     
mud4#d    ,a specimen in the ,museum of 

,practical ,geology1 in ,london1 still  
further  prolongs the period which must 
have elapsed between the death of the   
sea-  urchin1 and its burial by the     
,globigerinoe4 ,for the outward face of 
the  valve of a ,crania1 which is       
attached to a sea-urchin1 7,micraster71 
is  itself overrun by an incrusting     
coralline1 which spreads thence over    
more  or less of the surface of the     
sea-urchin4 ,it follows that1 after the 
upper valve of the ,crania fell off1 the
 surface of the attached valve  must    
have remained exposed long enough to    
allow of the growth of the  whole       
coralline1 since corallines do not live 
embedded in mud4#d    ,footnote #d3     
,elements of ,geology1 by ,sir ,charles 
,lyell1 ,bart4 ,f4,b4,s41  p4 #bc4      
,the progress of knowledge may1 one day1
 enable us to deduce from such  facts as
 these the maximum rate at which the    
chalk can have accumulated1  and thus to
 arrive at the minimum duration of the  
chalk period4 ,suppose  that the valve  

of the ,cronia upon which a coralline   
has fixed itself in  the way just       
described1 is so attached to the        
sea-urchin that no part of  it is more  
than an inch above the face upon which  
the sea-urchin rests4  ,then1 as the    
coralline could not have fixed itself1  
if the ,crania had  been covered up with
 chalk mud1 and could not have lived had
 itself been  so covered1 it follows1   
that an inch of chalk mud could not have
  accumulated within the time between   
the death and decay of the soft parts   
of the sea-urchin and the growth of the 
coralline to the full size which  it has
 attained4 ,if the decay of the soft    
parts of the sea-urchin2 the            
attachment1 growth to maturity1 and     
decay of the ,crania2 and the           
subsequent attachment and growth of the 
coralline1 took a year 7which is  a low 
estimate enough71 the accumulation of   
the inch of chalk must have  taken more 
than a year3 and the deposit of a       
thousand feet of chalk must1            

consequently1 have taken more than      
twelve thousand years4    ,the          
foundation of all this calculation is1  
of course1 a knowledge of the  length of
 time the ,crania and the coralline     
needed to attain their full  size2 and1 
on this head1 precise knowledge is at   
present wanting4 ,but  there are        
circumstances which tend to show1 that  
nothing like an inch of  chalk has      
accumulated during the life of a        
,crania2 and1 on any probable  estimate 
of the length of that life1 the chalk   
period must have had a  much longer     
duration than that thus roughly assigned
 to it4    ,thus1 not only is it certain
 that the chalk is the mud of an ancient
 sea-  bottom2 but it is no less        
certain1 that the chalk sea existed     
during an  extremely long period1 though
 we may not be prepared to give a       
precise  estimate of the length of that 
period in years4 ,the relative duration 
is  clear1 though the absolute duration 
may not be definable4 ,the attempt to   

affix any precise date to the period at 
which the chalk sea began1 or  ended1   
its existence1 is baffled by            
difficulties of the same kind4 ,but  the
 relative age of the cretaceous epoch   
may be determined with as great  ease   
and certainty as the long duration of   
that epoch4    ,you will have heard of  
the interesting discoveries recently    
made1 in  various parts of ,western     
,europe1 of flint implements1 obviously 
worked  into shape by human hands1 under
 circumstances which show conclusively  
that man is a very ancient denizen of   
these regions4 ,it has been proved  that
 the whole populations of ,europe1 whose
 existence has been revealed  to us in  
this way1 consisted of savages1 such as 
the ,esquimaux are now2  that1 in the   
country which is now ,france1 they      
hunted the reindeer1 and  were familiar 
with the ways of the mammoth and the    
bison4 ,the physical  geography of      
,france was in those days different from
 what it is now--the  river ,somme1 for 

instance1 having cut its bed a hundred  
feet deeper  between that time and this2
 and1 it is probable1 that the climate  
was  more like that of ,canada or       
,siberia1 than that of ,western ,europe4
    ,the existence of these people is   
forgotten even in the traditions of the 
oldest historical nations4 ,the name and
 fame of them had utterly vanished      
until a few years back2 and the amount  
of physical change which has been       
effected since their day renders it more
 than probable that1 venerable as  are  
some of the historical nations1 the     
workers of the chipped flints of  ,hoxne
 or of ,amiens are to them1 as they are 
to us1 in point of antiquity4  ,but1 if 
we assign to these hoar relics of       
long-vanished generations of  men the   
greatest age that can possibly be       
claimed for them1 they are not  older   
than the drift1 or boulder clay1 which1 
in comparison with the  chalk1 is but a 
very juvenile deposit4 ,you need go no  
further than your  own sea-board for    

evidence of this fact4 ,at one of the   
most charming  spots on the coast of    
,norfolk1 ,cromer1 you will see the     
boulder clay  forming a vast mass1 which
 lies upon the chalk1 and must          
consequently  have come into existence  
after it4 ,huge boulders of chalk are1  
in fact1  included in the clay1 and have
 evidently been brought to the position 
they now occupy by the same agency as   
that which has planted blocks of        
syenite from ,norway side by side with  
them4    ,the chalk1 then1 is certainly 
older than the boulder clay4 ,if you ask
 how  much1 ,i will again take you no   
further than the same spot upon your own
  coasts for evidence4 ,i have spoken of
 the boulder clay and drift as  resting 
upon the chalk4 ,that is not strictly   
true4 ,interposed between the  chalk and
 the drift is a comparatively           
insignificant layer1 containing         
vegetable matter4 ,but that layer tells 
a wonderful history4 ,it is full of     
stumps of trees standing as they grew4  

,fir-trees are there with their  cones1 
and hazel-bushes with their nuts2 there 
stand the stools of oak  and yew trees1 
beeches and alders4 ,hence this stratum 
is appropriately  called the forest-bed4
    ,it is obvious that the chalk must  
have been upheaved and converted into   
dry land1 before the timber trees could 
grow upon it4 ,as the bolls of  some of 
these trees are from two to three feet  
in diameter1 it is no less  clear that  
the dry land thus formed remained in the
 same condition for  long ages4 ,and not
 only do the remains of stately oaks and
 well-grown  firs testify to the        
duration of this condition of things1   
but additional  evidence to the same    
effect is afforded by the abundant      
remains of  elephants1 rhinoceroses1    
hippopotamuses1 and other great wild    
beasts1  which it has yielded to the    
zealous search of such men as the ,rev4 
,mr4  ,gunn4 ,when you look at such a   
collection as he has formed1 and bethink
  you that these elephantine bones did  

veritably carry their owners about1  and
 these great grinders crunch1 in the    
dark woods of which the forest-  bed is 
now the only trace1 it is impossible not
 to feel that they are as  good evidence
 of the lapse of time as the annual     
rings of the tree  stumps4    ,thus     
there is a writing upon the wall of     
cliffs at ,cromer1 and whoso runs  may  
read it4 ,it tells us1 with an authority
 which cannot be impeached1  that the   
ancient sea-bed of the chalk sea was    
raised up1 and remained dry  land1 until
 it was covered with forest1 stocked    
with the great game the  spoils of which
 have rejoiced your geologists4 ,how    
long it remained in  that condition     
cannot be said2 but the whirligig of    
time brought its  revenges in those days
 as in these4 ,that dry land1 with the  
bones and  teeth of generations of      
long-lived elephants1 hidden away among 
the  gnarled roots and dry leaves of its
 ancient trees1 sank gradually to the   
bottom of the icy sea1 which covered it 

with huge masses of drift and  boulder  
clay4 ,sea-beasts1 such as the walrus1  
now restricted to the  extreme north1   
paddled about where birds had twittered 
among the topmost  twigs of the         
fir-trees4 ,how long this state of      
things endured we know  not1 but at     
length it came to an end4 ,the upheaved 
glacial mud hardened  into the soil of  
modern ,norfolk4 ,forests grew once     
more1 the wolf and the  beaver replaced 
the reindeer and the elephant2 and at   
length what we call  the history of     
,england dawned4    ,thus you have1     
within the limits of your own county1   
proof that the chalk  can justly claim a
 very much greater antiquity than even  
the oldest  physical traces of mankind4 
,but we may go further and demonstrate1 
by  evidence of the same authority as   
that which testifies to the existence   
of the father of men1 that the chalk is 
vastly older than ,adam himself4  ,the  
,book of ,genesis informs us that ,adam1
 immediately upon his creation1  and    

before the appearance of ,eve1 was      
placed in the ,garden of ,eden4 ,the    
problem of the geographical position of 
,eden has greatly vexed the  spirits of 
the learned in such matters1 but there  
is one point respecting  which1 so far  
as ,i know1 no commentator has ever     
raised a doubt4 ,this is1  that of the  
four rivers which are said to run out of
 it1 ,euphrates and  ,hiddekel are      
identical with the rivers now known by  
the names of  ,euphrates and ,tigris4   
,but the whole country in which these   
mighty rivers  take their origin1 and   
through which they run1 is composed of  
rocks which  are either of the same age 
as the chalk1 or of later date4 ,so that
 the  chalk must not only have been     
formed1 but1 after its formation1 the   
time  required for the deposit of these 
later rocks1 and for their upheaval     
into dry land1 must have elapsed1 before
 the smallest brook which feeds  the    
swift stream of the great river1 the    
river of ,babylon1 began to  flow4      

,thus1 evidence which cannot be         
rebutted1 and which need not be         
strengthened1 though if time permitted  
,i might indefinitely increase its      
quantity1 compels you to believe that   
the earth1 from the time of the  chalk  
to the present day1 has been the theatre
 of a series of changes as  vast in     
their amount1 as they were slow in their
 progress4 ,the area on  which we stand 
has been first sea and then land1 for at
 least four  alternations2 and has      
remained in each of these conditions for
 a period  of great length4    ,nor have
 these wonderful metamorphoses of sea   
into land1 and of land into  sea1 been  
confined to one corner of ,england4     
,during the chalk period1 or  cretaceous
 epoch1 not one of the present great    
physical features of the  globe was in  
existence4 ,our great mountain ranges1  
,pyrenees1 ,alps1  ,himalayas1 ,andes1  
have all been upheaved since the chalk  
was deposited1  and the cretaceous sea  
flowed over the sites of ,sinai and     

,ararat4 ,all  this is certain1 because 
rocks of cretaceous1 or still later1    
date have  shared in the elevatory      
movements which gave rise to these      
mountain  chains2 and may be found      
perched up1 in some cases1 many thousand
 feet  high upon their flanks4 ,and     
evidence of equal cogency demonstrates  
that1  though1 in ,norfolk1 the         
forest-bed rests directly upon the      
chalk1 yet it  does so1 not because the 
period at which the forest grew         
immediately  followed that at which the 
chalk was formed1 but because an immense
 lapse  of time1 represented elsewhere  
by thousands of feet of rock1 is not    
indicated at ,cromer4    ,i must ask you
 to believe that there is no less       
conclusive proof that a  still more     
prolonged succession of similar changes 
occurred1 before the  chalk was         
deposited4 ,nor have we any reason to   
think that the first term  in the series
 of these changes is known4 ,the oldest 
sea-beds preserved to  us are sands1 and

 mud1 and pebbles1 the wear and tear of 
rocks which were  formed in still older 
oceans4    ,but1 great as is the        
magnitude of these physical changes of  
the world1  they have been accompanied  
by a no less striking series of         
modifications  in its living            
inhabitants4 ,all the great classes of  
animals1 beasts of  the field1 fowls of 
the air1 creeping things1 and things    
which dwell in  the waters1 flourished  
upon the globe long ages before the     
chalk was  deposited4 ,very few1        
however1 if any1 of these ancient forms 
of animal  life were identical with     
those which now live4 ,certainly not one
 of the  higher animals was of the same 
species as any of those now in          
existence4  ,the beasts of the field1 in
 the days before the chalk1 were not our
  beasts of the field1 nor the fowls of 
the air such as those which the eye  of 
men has seen flying1 unless his         
antiquity dates infinitely further  back
 than we at present surmise4 ,if we     

could be carried back into those  times1
 we should be as one suddenly set down  
in ,australia before it was  colonized4 
,we should see mammals1 birds1 reptiles1
 fishes1 insects1  snails1 and the like1
 clearly recognizable as such1 and yet  
not one of  them would be just the same 
as those with which we are familiar1 and
 many  would be extremely different4    
,from that time to the present1 the     
population of the world has undergone   
slow and gradual1 but incessant1        
changes4 ,there has been no grand       
catastrophe--no destroyer has swept away
 the forms of life of one period1  and  
replaced them by a totally new creation3
 but one species has vanished  and      
another has taken its place2 creatures  
of one type of structure have           
diminished1 those of another have       
increased1 as time has passed on4 ,and  
thus1 while the differences between the 
living creatures of the time  before the
 chalk and those of the present day     
appear startling1 if placed  side by    

side1 we are led from one to the other  
by the most gradual  progress1 if we    
follow the course of ,nature through the
 whole series of  those relics of her   
operations which she has left behind4   
,it is by the  population of the chalk  
sea that the ancient and the modern     
inhabitants  of the world are most      
completely connected4 ,the groups which 
are dying  out flourish1 side by side1  
with the groups which are now the       
dominant  forms of life4 ,thus the chalk
 contains remains of those strange      
flying  and swimming reptiles1 the      
pterodactyl1 the ichthyosaurus1 and the 
plesiosaurus1 which are found in no     
later deposits1 but abounded in         
preceding ages4 ,the chambered shells   
called ammonites and belemnites1  which 
are so characteristic of the period     
preceding the cretaceous1 in  like      
manner die with it4    ,but1 amongst    
these fading remainders of a previous   
state of things1 are  some very modern  
forms of life1 looking like ,yankee     

pedlars among a tribe  of ,red ,indians4
 ,crocodiles of modern type appear2 bony
 fishes1 many of  them very similar to  
existing species1 almost supplant the   
forms of fish  which predominate in more
 ancient seas2 and many kinds of living 
shell-  fish first become known to us in
 the chalk4 ,the vegetation acquires a  
modern aspect4 ,a few living animals are
 not even distinguishable as  species1  
from those which existed at that remote 
epoch4 ,the ,globigerina  of the present
 day1 for example1 is not different     
specifically from that  of the chalk2   
and the same maybe said of many other   
,foraminifera4 ,i  think it probable    
that critical and unprejudiced          
examination will show  that more than   
one species of much higher animals have 
had a similar  longevity2 but the only  
example which ,i can at present give    
confidently  is the snake's-head        
lampshell 7,terebratulina caput         
serpentis71 which  lives in our ,english
 seas and abounded 7as ,terebratulina   

striata of  authors7 in the chalk4      
,the longest line of human ancestry must
 hide its diminished head before  the   
pedigree of this insignificant          
shell-fish4 ,we ,englishmen are proud to
  have an ancestor who was present at   
the ,battle of ,hastings4 ,the ancestors
  of ,terebratulina caput serpentis may 
have been present at a battle of        
,ichthyosauria in that part of the sea  
which1 when the chalk was  forming1     
flowed over the site of ,hastings4      
,while all around has changed1  this    
,terebratulina has peacefully propagated
 its species from  generation to        
generation1 and stands to this day1 as a
 living testimony  to the continuity of 
the present with the past history of the
 globe4      ,up to this moment ,i have 
stated1 so far as ,i know1 nothing but  
well-  authenticated facts1 and the     
immediate conclusions which they force  
upon  the mind4 ,but the mind is so     
constituted that it does not willingly  
rest  in facts and immediate causes1 but

 seeks always after a knowledge of the  
remoter links in the chain of causation4
    ,taking the many changes of any     
given spot of the earth's surface1 from 
sea to land and from land to sea1 as an 
established fact1 we cannot  refrain    
from asking ourselves how these changes 
have occurred4 ,and when  we have       
explained them--as they must be         
explained--by the alternate slow        
movements of elevation and depression   
which have affected the crust of  the   
earth1 we go still further back1 and    
ask1 ,why these movements8    ,i am not 
certain that any one can give you a     
satisfactory answer to that  question4  
,assuredly ,i cannot4 ,all that can be  
said1 for certain1 is1 that  such       
movements are part of the ordinary      
course of nature1 inasmuch as  they are 
going on at the present time4 ,direct   
proof may be given1 that  some parts of 
the land of the northern hemisphere are 
at this moment  insensibly rising and   
others insensibly sinking2 and there is 

indirect1  but perfectly satisfactory1  
proof1 that an enormous area now covered
 by  the ,pacific has been deepened     
thousands of feet1 since the present    
inhabitants of that sea came into       
existence4 ,thus there is not a shadow  
of a reason for believing that the      
physical changes of the globe1 in past  
times1 have been effected by other than 
natural causes4 ,is there any more      
reason for believing that the           
concomitant modifications in the forms  
of  the living inhabitants of the globe 
have been brought about in other  ways8 
,before attempting to answer this       
question1 let us try to form a distinct 
mental picture of what has happened in  
some special case4 ,the crocodiles  are 
animals which1 as a group1 have a very  
vast antiquity4 ,they abounded  ages    
before the chalk was deposited2 they    
throng the rivers in warm  climates1 at 
the present day4 ,there is a difference 
in the form of the  joints of the       
back-bone1 and in some minor            

particulars1 between the  crocodiles of 
the present epoch and those which lived 
before the chalk2  but1 in the          
cretaceous epoch1 as ,i have already    
mentioned1 the crocodiles  had assumed  
the modern type of structure4           
,notwithstanding this1 the  crocodiles  
of the chalk are not identically the    
same as those which lived  in the times 
called older tertiary1 which succeeded  
the cretaceous  epoch2 and the          
crocodiles of the older tertiaries are  
not identical with  those of the newer  
tertiaries1 nor are these identical with
 existing  forms4 ,i leave open the     
question whether particular species may 
have  lived on from epoch to epoch4 ,but
 each epoch has had its peculiar        
crocodiles2 though all1 since the chalk1
 have belonged to the modern  type1 and 
differ simply in their proportions1 and 
in such structural  particulars as are  
discernible only to trained eyes4       
,how is the existence of this long      
succession of different species of      

crocodiles to be accounted for8 ,only   
two suppositions seem to be open to     
us--,either each species of crocodile   
has been specially created1 or it  has  
arisen out of some pre-existing form by 
the operation of natural  causes4       
,choose your hypothesis2 ,i have chosen 
mine4 ,i can find no  warranty for      
believing in the distinct creation of a 
score of successive  species of         
crocodiles in the course of countless   
ages of time4 ,science  gives no        
countenance to such a wild fancy2 nor   
can even the perverse  ingenuity of a   
commentator pretend to discover this    
sense1 in the simple  words in which the
 writer of ,genesis records the         
proceedings of the fifth  and six days  
of the ,creation4    ,on the other hand1
 ,i see no good reason for doubting the 
necessary  alternative1 that all these  
varied species have been evolved from   
pre-  existing crocodilian forms1 by the
 operation of causes as completely a    
part of the common order of nature as   

those which have effected the  changes  
of the inorganic world4 ,few will       
venture to affirm that the  reasoning   
which applies to crocodiles loses its   
force among other  animals1 or among    
plants4 ,if one series of species has   
come into  existence by the operation of
 natural causes1 it seems folly to deny 
that  all may have arisen in the same   
way4    ,a small beginning has led us to
 a great ending4 ,if ,i were to put the 
bit  of chalk with which we started into
 the hot but obscure flame of burning   
hydrogen1 it would presently shine like 
the sun4 ,it seems to me that this      
physical metamorphosis is no false image
 of what has been the result of  our    
subjecting it to a jet of fervent1      
though nowise brilliant1 thought        
to-night4 ,it has become luminous1 and  
its clear rays1 penetrating the  abyss  
of the remote past1 have brought within 
our ken some stages of the  evolution of
 the earth4 ,and in the shifting without
 haste1 but without  rest of the land   

and sea1 as in the endless variation of 
the forms  assumed by living beings1 we 
have observed nothing but the natural   
product of the forces originally        
possessed by the substance of the       
universe4        ,,ii      ,,the        
,,problems ,,of ,,the ,,deep ,,sea      
#ahgc    ,on the #bast of ,december1    
#ahgb1 ,h4,m4,s4 ,challenger1 an        
eighteen gun  corvette1 of #b1jjj tons  
burden1 sailed from ,portsmouth harbour 
for a  three1 or perhaps four1 years'   
cruise4 ,no man-of-war ever left that   
famous port before with so singular an  
equipment4 ,two of the eighteen         
sixty-eight pounders of the             
,challenger's armament remained to      
enable  her to speak with effect to     
sea-rovers1 haply devoid of any respect 
for  science1 in the remote seas for    
which she is bound2 but the main-deck   
was1 for the most part1 stripped of its 
war-like gear1 and fitted up with       
physical1 chemical1 and biological      
laboratories2 ,photography had its dark 

cabin2 while apparatus for dredging1    
trawling1 and sounding2 for  photometers
 and for thermometers1 filled the space 
formerly occupied by  guns and          
gun-tackle1 pistols and cutlasses4      
,the crew of the ,challenger match her  
fittings4 ,captain ,nares1 his  officers
 and men1 are ready to look after the   
interests of hydrography1  work the     
ship1 and1 if need be1 fight her as     
seamen should2 while there  is a staff  
of scientific civilians1 under the      
general direction of ,dr4  ,wyville     
,thomson1 ,f4,r4,s4 7,professor of      
,natural ,history in ,edinburgh         
,university by rights1 but at present   
detached for duty in partibus71  whose  
business it is to turn all the          
wonderfully packed stores of  appliances
 to account1 and to accumulate1 before  
the ship returns to  ,england1 such     
additions to natural knowledge as shall 
justify the labour  and cost involved in
 the fitting out and maintenance of the 
expedition4    ,under the able and      

zealous superintendence of the          
,hydrographer1 ,admiral  ,richards1     
every precaution which experience and   
forethought could devise  has been taken
 to provide the expedition with the     
material conditions of  success2 and it 
would seem as if nothing short of wreck 
or pestilence1  both most improbable    
contingencies1 could prevent the        
,challenger from  doing splendid work1  
and opening up a new era in the history 
of  scientific voyages4    ,the dispatch
 of this expedition is the culmination  
of a series of such  enterprises1       
gradually increasing in magnitude and   
importance1 which the  ,admiralty1      
greatly to its credit1 has carried out  
for some years past2  and the history of
 which is given by ,dr4 ,wyville        
,thomson in the  beautifully illustrated
 volume entitled ,the ,depths of the    
,sea1  published since his departure4   
,in the spring of the year #ahfh1 my    
friend ,dr4 ,w4,b4 ,carpenter1 at that  
time one of the ,vice-,presidents of the

 ,royal ,society1 was with me in        
,ireland1 where we were working out     
together the structure and development  
of the ,crinoids4 ,i had long previously
 had a profound conviction that the     
land of promise for the naturalist1 the 
only remaining region where there  were 
endless novelties of extraordinary      
interest ready to the hand which  had   
the means of gathering them1 was the    
bottom of the deep sea4 ,i had  even had
 a glimpse of some of these treasures1  
for ,i had seen1 the year  before1 with 
,prof4 ,sars1 the forms which ,i have   
already mentioned dredged  by his son at
 a depth of #cjj to #djj fathoms off the
 ,loffoten ,islands4 ,i  propounded my  
views to my fellow-labourer1 and we     
discussed the subject  many times over  
our microscopes4 ,i strongly urged ,dr4 
,carpenter to use  his influence at     
head-quarters to induce the ,admiralty1 
probably through  the ,council of the   
,royal ,society1 to give us the use of a
 vessel properly  fitted with dredging  

gear and all necessary scientific       
apparatus1 that  many heavy questions as
 to the state of things in the depths of
 the  ocean1 which were still in a state
 of uncertainty1 might be definitely    
settled4 ,after full consideration1 ,dr4
 ,carpenter promised his hearty co-     
operation1 and we agreed that ,i should 
write to him on his return to  ,london1 
indicating generally the results which  
,i anticipated1 and  sketching out what 
,i conceived to be a promising line of  
inquiry4 ,the  ,council of the ,royal   
,society warmly supported the proposal2 
and ,i give  here in chronological order
 the short and eminently satisfactory   
correspondence which led to the         
,admiralty placing at the disposal of   
,dr4  ,carpenter and myself the gunboat 
,lightninq1 under the command of ,staff-
  ,commander ,may1 ,r4,n41 in the summer
 of #ahfh1 for a trial cruise to the    
,north of ,scotland1 and afterwards to  
the much wider surveys in ,h4,m4,s4     
,porcupine1 ,captain ,calver1 ,r4,n41   

which were made with the additional     
association of ,mr4 ,gwyn ,jeffreys1 in 
the summers of the years #ahfi and      
#ahgj4a    ,footnote #a3 ,the ,depths of
 the ,sea1 pp4 #di-ej4    ,plain men may
 be puzzled to understand why ,dr4      
,wyville ,thomson1 not being  a cynic1  
should relegate the ,land of ,promise to
 the bottom of the deep  sea1 they may  
still more wonder what manner of milk   
and honey the  ,challenger expects to   
find2 and their perplexity may well rise
 to its  maximum1 when they seek to     
divine the manner in which that milk and
 honey  are to be got out of so         
inaccessible a ,canaan4 ,i will1        
therefore1  endeavour to give some      
answer to these questions in an order   
the reverse  of that in which ,i have   
stated them4    ,apart from hooks1 and  
lines1 and ordinary nets1 fishermen     
have1 from time  immemorial1 made use of
 two kinds of implements for getting at 
sea-  creatures which live beyond       
tide-marks--these are the dredge and the

  trawl4 ,the dredge is used by         
oyster-fishermen4 ,imagine a large bag1 
the  mouth of which has the shape of an 
elongated parallelogram1 and is         
fastened to an iron frame of the same   
shape1 the two long sides of this  rim  
being fashioned into scrapers4 ,chains  
attach the ends of the frame to  a stout
 rope1 so that when the bag is dragged  
along by the rope the edge  of one of   
the scrapers rests on the ground1 and   
scrapes whatever it  touches into the   
bag4 ,the oyster-dredger takes one of   
these machines in  his boat1 and when he
 has reached the oyster-bed the dredge  
is tossed  overboard2 as soon as it has 
sunk to the bottom the rope is paid out 
sufficiently to prevent it from pulling 
the dredge directly upwards1 and  is    
then made fast while the boat goes      
ahead4 ,the dredge is thus dragged      
along and scrapes oysters and other     
sea-animals and plants1 stones1 and  mud
 into the bag4 ,when the dredger judges 
it to be full he hauls it up1  picks out

 the oysters1 throws the rest overboard1
 and begins again4    ,dredging in      
shallow water1 say ten to twenty        
fathoms1 is an easy  operation enough2  
but the deeper the dredger goes1 the    
heavier must be  his vessel1 and the    
stouter his tackle1 while the operation 
of hauling up  becomes more and more    
laborious4 ,dredging in #aej fathoms is 
very hard  work1 if it has to be carried
 on by manual labour2 but by the use of 
the  donkey-engine to supply power1#b   
and of the contrivances known as        
accumulators1 to diminish the risk of   
snapping the dredge rope by the  rolling
 and pitching of the vessel1 the dredge 
has been worked deeper and  deeper1     
until at last1 on the #bbnd of ,july1   
#ahfi1 ,h4,m4,s4 ,porcupine  being in   
the ,bay of ,biscay1 ,captain ,calver1  
her commander1 performed the            
unprecedented feat of dredging in #b1dce
 fathoms1 or #ad1faj feet1 a depth      
nearly equal to the height of ,mont     
,blanc4 ,the dredge was rapidly hauled  

on deck at one o'clock in the morning of
 the #bcrd1 after an absence of  #g-a_/d
 hours1 and a journey of upwards of     
eight statute miles1 with a  hundred    
weight and a half of solid contents4    
,footnote #b3 ,the emotional side of the
 scientific nature has its              
singularities4 ,many persons will call  
to mind a certain philosopher's         
tenderness over his watch--the little   
creature--which was so singularly  lost 
and found again4 ,but ,dr4 ,wyville     
,thomson surpasses the owner of the     
watch in his loving-kindness towards a  
donkey-engine4 ,this little engine  was 
the comfort of our lives4 ,once or twice
 it was overstrained1 and then  we      
pitied the willing little thing1 panting
 like an overtaxed horse4    ,the trawl 
is a sort of net for catching those fish
 which habitually live  at the bottom of
 the sea1 such as soles1 plaice1 turbot1
 and gurnett4 ,the  mouth of the net may
 be thirty or forty feet wide1 and one  
edge of its  mouth is fastened to a beam

 of wood of the same length4 ,the two   
ends of  the beam are supported by      
curved pieces of iron1 which raise the  
beam and  the edge of the net which is  
fastened to it1 for a short distance1   
while  the other edge of the mouth of   
the net trails upon the ground4 ,the    
closed  end of the net has the form of a
 great pouch2 and1 as the beam is       
dragged  along1 the fish1 roused from   
the bottom by the sweeping of the net1  
readily pass into its mouth and         
accumulate in the pouch at its end4     
,after  drifting with the tide for six  
or seven hours the trawl is hauled up1  
the  marketable fish are picked out1 the
 others thrown away1 and the trawl  sent
 overboard for another operation4       
,more than a thousand sail of well-found
 trawlers are constantly engaged  in    
sweeping the seas around our coast in   
this way1 and it is to them that  we owe
 a very large proportion of our supply  
of fish4 ,the difficulty of  trawling1  
like that of dredging1 rapidly increases

 with the depth at  which the operation 
is performed2 and1 until the other day1 
it is  probable that trawling at so     
great a depth as #ajj fathoms was       
something  unheard of4 ,but the first   
news from the ,challenger opens up new  
possibilities for the trawl4    ,dr4    
,wyville ,thomson writes 7,nature1      
,march #bj1 #ahgc73--    ,for the first 
two or three hauls in very deep water   
off the coast of  ,portugal1 the dredge 
came up filled with the usual ',atlantic
 ooze1'  tenacious and uniform          
throughout1 and the work of hours1 in   
sifting1 gave  the very smallest        
possible result4 ,we were extremely     
anxious to get some  idea of the general
 character of the ,fauna1 and           
particularly of the  distribution of the
 higher groups2 and after various       
suggestions for  modification of the    
dredge1 it was proposed to try the      
ordinary trawl4 ,we  had a compact      
trawl1 with a #ae-;feet beam1 on board1 
and we sent it down  off ,cape ,st4     

,vincent at a depth of #fjj fathoms4    
,the experiment looked  hazardous1 but1 
to our great satisfaction1 the trawl    
came up all right  and contained1 with  
many of the larger invertebrate1 several
 fishes4444  ,after the first attempt we
 tried the trawl several times at depths
 of  #ajij1 #aebe1 and1 finally1 #babe  
fathoms1 and always with success4    ,to
 the coral-fishers of the               
,mediterranean1 who seek the precious   
red  coral1 which grows firmly fixed to 
rocks at a depth of sixty to eighty     
fathoms1 both the dredge and the trawl  
would be useless4 ,they1 therefore1     
have recourse to a sort of frame1 to    
which are fastened long bundles of      
loosely netted hempen cord1 and which is
 lowered by a rope to the depth  at     
which the hempen cords can sweep over   
the surface of the rocks and  break off 
the coral1 which is brought up entangled
 in the cords4 ,a  similar contrivance  
has arisen out of the necessities of    
deep-sea  exploration4    ,in the course

 of the dredging of the ,porcupine1 it  
was frequently found  that1 while few   
objects of interest were brought up     
within the dredge1  many living         
creatures came up sticking to the       
outside of the dredge-bag1  and even to 
the first few fathoms of the            
dredge-rope4 ,the mouth of the  dredge  
doubtless rapidly filled with mud1 and  
thus the things it should  have brought 
up were shut out4 ,to remedy this       
inconvenience ,captain  ,calver devised 
an arrangement not unlike that employed 
by the coral-  fishers4 ,he fastened    
half a dozen swabs1 such as are used for
 drying  decks1 to the dredge4 ,a swab  
is something like what a birch-broom    
would  be if its twigs were made of     
long1 coarse1 hempen yarns4 ,these      
dragged  along after the dredge over the
 surface of the mud1 and entangled the  
creatures living there--multitudes of   
which1 twisted up in the strands of  the
 swabs1 were brought to the surface with
 the dredge4 ,a further  improvement was

 made by attaching a long iron bar to   
the bottom of the  dredge bag1 and      
fastening large bunches of teased-out   
hemp to the end of  this bar4 ,these    
tangles bring up immense quantities of  
such animals as  have long arms1 or     
spines1 or prominences which readily    
become caught in  the hemp1 but they are
 very destructive to the fragile        
organisms which  they imprison2 and1 now
 that the trawl can be successfully     
worked at the  greatest depths1 it may  
be expected to supersede them2 at least1
 wherever  the ground is soft enough to 
permit of trawling4    ,it is obvious   
that between the dredge1 the trawl1 and 
the tangles1 there  is little chance for
 any organism1 except such as are able  
to burrow  rapidly1 to remain safely at 
the bottom of any part of the sea which 
the  ,challenger undertakes to explore4 
,and1 for the first time in the  history
 of scientific exploration1 we have a   
fair chance of learning what  the       
population of the depths of the sea is  

like in the most widely  different parts
 of the world4    ,and now arises the   
next question4 ,the means of exploration
 being fairly  adequate1 what forms of  
life may be looked for at these vast    
depths8    ,the systematic study of the 
,distribution of living beings is the   
most  modern branch of ,biological      
,science1 and came into existence long  
after  ,morphology and ,physiology had  
attained a considerable development4    
,this  naturally does not imply that1   
from the time men began to observe      
natural  phenomena1 they were ignorant  
of the fact that the animals and plants 
of  one part of the world are different 
from those in other regions2 or that    
those of the hills are different from   
those of the plains in the same  region2
 or finally that some marine creatures  
are found only in the  shallows1 while  
others inhabit the deeps4 ,nevertheless1
 it was only after  the discovery of    
,america that the attention of          
naturalists was powerfully  drawn to the

 wonderful differences between the      
animal population of the  central and   
southern parts of the new world and that
 of those parts of  the old world which 
lie under the same parallels of         
latitude4 ,so far back  as #affg        
,abraham ,mylius1 in his treatise ,de   
,animalium origine et  migratione1      
populorum1 argues that1 since there are 
innumerable species  of animals in      
,america which do not exist elsewhere1  
they must have been  made and placed    
there by the ,deity3 ,buffon no less    
forcibly insists upon  the difference   
between the ,faunae of the old and new  
world4 ,but the first  attempt to gather
 facts of this order into a whole1 and  
to coordinate  them into a series of    
generalizations1 or laws of             
,geographical  ,distribution1 is not a  
century old1 and is contained in the    
,specimen  ,zoologiae ,geographicae     
,quadrupedum ,domicilia et ,migrationes 
sistens1  published1 in #aggg1 by the   
learned ,brunswick ,professor1 ,eberhard

  ,zimmermann1 who illustrates his work 
by what he calls a ,tabula              
,zoographica1 which is the oldest       
distributional map known to me4    ,in  
regard to matters of fact1 ,zimmermann's
 chief aim is to show that  among       
terrestrial mammals1 some occur all over
 the world1 while others  are restricted
 to particular areas of greater or      
smaller extent2 and that  the abundance 
of species follows temperature1 being   
greatest in warm and  least in cold     
climates4 ,but marine animals1 he       
thinks1 obey no such law4  ,the ,arctic 
and ,atlantic seas1 he says1 are as full
 of fishes and other  animals as those  
of the tropics4 ,it is1 therefore1 clear
 that cold does  not affect the dwellers
 in the sea as it does land animals1 and
 that this  must be the case follows    
from the fact that sea water1 propter   
varias  quas continet bituminis         
spiritusque particulas1 freezes with    
much more  difficulty than fresh water4 
,on the other hand1 the heat of the     

,equatorial sun penetrates but a short  
distance below the surface of the       
ocean4 ,moreover1 according to          
,zimmermann1 the incessant disturbance  
of  the mass of the sea by winds and    
tides1 so mixes up the warm and the cold
  that life is evenly diffused and      
abundant throughout the ocean4    ,in   
#ahaj1 ,risso1 in his work on the       
,ichthyology of ,nice1 laid the         
foundation of what has since been termed
 bathymetrical distribution1 or         
distribution in depth1 by showing that  
regions of the sea bottom of  different 
depths could be distinguished by the    
fishes which inhabit them4  ,there was  
the littoral region between tide marks  
with its sand-eels1  pipe fishes1 and   
blennies3 the seaweed region1 extending 
from low-  water-mark to a depth of #dej
 feet1 with its wrasses1 rays1 and flat 
fish2  and the deep-sea region1 from    
#dej feet to #aejj feet or more1 with   
its file-fish1 sharks1 gurnards1 cod1   
and sword-fish4    ,more than twenty    

years later1 ,m4,m4 ,audouin and ,milne 
,edwards carried out  the principle of  
distinguishing the ,faunae of different 
zones of depth  much more minutely1 in  
their ,recherches pour servir           
l',histoire  ,naturelle du ,littoral de 
la ,france1 published in #ahcb4    ,they
 divide the area included between       
highwater-mark and lowwater-mark of     
spring tides 7which is very extensive1  
on account of the great rise and  fall  
of the tide on the ,normandy coast about
 ,st4 ,malo1 where their  observations  
were made7 into four zones1 each        
characterized by its  peculiar          
invertebrate inhabitants4 ,beyond the   
fourth region they  distinguish a fifth1
 which is never uncovered1 and is       
inhabited by  oysters1 scallops1 and    
large starfishes and other animals4     
,beyond this  they seem to think that   
animal life is absent4#c    ,footnote   
#c3 ,enfin plus has encore1 c'est--dire 
alors loin des ctes1  le fond des eaux  
ne parat plus tre habit1 du moms dans   

nos mers1 par  aucun de ces animaux 7#a4
 c4 tom4 i4 p4 #bcg74 ,the ces animaux  
leaves  the meaning of the authors      
doubtful4    ,audouin and ,milne        
,edwards were the first to see the      
importance of the  bearing of a         
knowledge of the manner in which marine 
animals are  distributed in depth1 on   
geology4 ,they suggest that1 by this    
means1 it  will be possible to judge    
whether a fossiliferous stratum was     
formed upon  the shore of an ancient    
sea1 and even to determine whether it   
was  deposited in shallower or deeper   
water on that shore2 the association of 
shells of animals which live in         
different zones of depth will prove that
  the shells have been transported into 
the position in which they are  found2  
while1 on the other hand1 the absence of
 shells in a deposit will  not justify  
the conclusion that the waters in which 
it was formed were  devoid of animal    
inhabitants1 inasmuch as they might have
 been only too  deep for habitation4    

,the new line of investigation thus     
opened by the ,french naturalists was   
followed up by the ,norwegian1 ,sars1 in
 #ahce1 by ,edward ,forbes1 in our own  
country1 in #ahdj1d and by ,oersted1 in 
,denmark1 a few years later4 ,the       
genius of ,forbes1 combined with his    
extensive knowledge of botany1          
invertebrate zoology1 and geology1      
enabled him to do more than any of his  
compeers1 in bringing the importance of 
distribution in depth into  notice2 and 
his researches in the ,aegean ,sea1 and 
still more his  remarkable paper ,on the
 ,geological ,relations of the existing 
,fauna and  ,flora of the ,british      
,isles1 published in #ahdf1 in the first
 volume of  the ,memoirs of the         
,geological ,survey of ,great ,britain1 
attracted  universal attention4         
,footnote #d3 ,in the paper in the      
,memoirs of the ,survey cited further   
on1 ,forbes writes3--    ,in an essay   
',on the ,association of ,mollusca on   
the ,british ,coasts1  considered with  

reference to ,pleistocene ,geology1'    
printed in the  ,edinburgh ,academic    
,annual for #ahdj1 ,i described the     
mollusca1 as  distributed on our shores 
and seas1 in four great zones or        
regions1  usually denominated ',the     
,littoral zone1' ',the region of        
,laminariae1' ',the  region of          
,coral-lines1' and ',the region of      
,corals4' ,an extensive series  of      
researches1 chiefly conducted by the    
members of the committee  appointed by  
the ,british ,association to investigate
 the marine geology of  ,britain by     
means of the dredge1 have not           
invalidated this classification1  and   
the researches of ,professor ,lovn1 in  
the ,norwegian and ,lapland seas1  have 
borne out their correctness ,the first  
two of the regions above  mentioned had 
been previously noticed by ,lamoureux1  
in his account of the  distribution     
7vertically7 of sea-weeds1 by ,audouin  
and ,milne ,edwards in  their           
,observations on the ,natural ,history  

of the coast of ,france1 and  by ,sars  
in the preface to his ,beskrivelser og  
,jagttayelser4    ,on the coasts of the 
,british ,islands1 ,forbes distinguishes
 four zones or  regions1 the ,littoral  
7between tide marks71 the ,laminarian   
7between  lowwater-mark and #ae         
fathoms71 the ,coralline 7from #ae to   
#ej fathoms71 and  the ,deep sea or     
,coral region 7from #ej fathoms to      
beyond #ajj fathoms74  ,but1 in the     
deeper waters of the ,aegean ,sea1      
between the shore and a depth  of #cjj  
fathoms1 ,forbes was able to make out no
 fewer than eight zones of  life1 in the
 course of which the number and variety 
of forms gradually  diminished until1   
beyond #cjj fathoms1 life disappeared   
altogether4 ,hence  it appeared as if   
descent in the sea had much the same    
effect on life1 as  ascent on land4     
,recent investigations appear to show   
that ,forbes was  right enough in his   
classification of the facts of          
distribution in depth  as they are to be

 observed in the ,aegean2 and though1 at
 the time he  wrote1 one or two         
observations were extant which might    
have warned him  not to generalize too  
extensively from his ,aegean experience1
 his own  dredging work was so much more
 extensive and systematic than that of  
any  other naturalist1 that it is not   
wonderful he should have felt justified 
in building upon it4 ,nevertheless1 so  
far as the limit of the range of  life  
in depth goes1 ,forbes' conclusion has  
been completely negatived1 and  the     
greatest depths yet attained show not   
even an approach to a zero of  life3--  
,during the several cruises of ,h4,m4   
ships ,lightning and ,porcupine in  the 
years #ahfh1 #ahfi1 and #ahgj1 says ,dr4
 ,wyville ,thomson1 fifty-seven  hauls  
of the dredge were taken in the         
,atlantic at depths beyond #ejj         
fathoms1 and sixteen at depths beyond   
#a1jjj fathoms1 and1 in all cases1  life
 was abundant4 ,in #ahfi1 we took two   
casts in depths greater than  #b1jjj    

fathoms4 ,in both of these life was     
abundant2 and with the deepest  cast1   
#b1dce fathoms1 off the month of the    
,bay of ,biscay1 we took living1        
well-marked and characteristic examples 
of all the five invertebrate sub-       
kingdoms4 ,and thus the question of the 
existence of abundant animal life  at   
the bottom of the sea has been finally  
settled and for all depths1 for  there  
is no reason to suppose that the depth  
anywhere exceeds between  three and four
 thousand fathoms2 and if there be      
nothing in the  conditions of a depth of
 #b1ejj fathoms to prevent the full     
development of  a varied ,fauna1 it is  
impossible to suppose that even an      
additional  thousand fathoms would make 
any great difference4#e    ,footnote #e3
 ,the ,depths of the ,sea1 p4 #cj4      
,results of a similar kind1  obtained by
 previous observers1 are stated at      
length in the sixth  chapter1 pp4       
#bfg-bhj4 ,the dredgings carried out by 
,count ,pourtales1 under  the authority 

of ,professor ,peirce1 the              
,superintendent of the ,united  ,states 
,coast ,survey1 in the years #ahfg1     
#ahfh1 and #ahfi1 are particularly      
noteworthy1 and it is probably not too  
much to say1 in the words of  ,professor
 ,agassiz1 that we owe to the coast     
survey the first broad and              
comprehensive basis for an exploration  
of the sea bottom on a large  scale1    
opening a new era in zoological and     
geological research4    ,as ,dr4        
,wyville ,thomson's recent letter1 cited
 above1 shows1 the use of  the trawl1 at
 great depths1 has brought to light a   
still greater  diversity of life4       
,fishes came up from a depth of #fjj to 
more than #a1jjj  fathoms1 all in a     
peculiar condition from the expansion of
 the air  contained in their bodies4 ,on
 their relief from the extreme pressure1
  their eyes1 especially1 had a singular
 appearance1 protruding like great      
globes from their heads4 ,bivalve and   
univalve mollusca seem to be rare at    

the greatest depths2 but starfishes1 sea
 urchins and other echinoderms1         
zoophytes1 sponges1 and protozoa abound4
    ,it is obvious that the ,challenger 
has the privilege of opening a new      
chapter in the history of the living    
world4 ,she cannot send down her        
dredges and her trawls into these virgin
 depths of the great ocean  without     
bringing up a discovery4 ,even though   
the thing itself may be  neither rich   
nor rare1 the fact that it came from    
that depth1 in that  particular latitude
 and longitude1 will be a new fact in   
distribution1  and1 as such1 have a     
certain importance4    ,but it may be   
confidently assumed that the things     
brought up will very  frequently be     
zoological novelties2 or1 better still1 
zoological  antiquities1 which1 in the  
tranquil and little-changed depths of   
the  ocean1 have escaped the causes of  
destruction at work in the shallows1    
and represent the predominant population
 of a past age4    ,it has been seen    

that ,audouin and ,milne ,edwards       
foresaw the general  influence of the   
study of distribution in depth upon the 
interpretation  of geological phenomena4
 ,forbes connected the two orders of    
inquiry still  more closely2 and in the 
thoughtful essay ,on the connection     
between the  distribution of the        
existing ,fauna and ,flora of the       
,british ,isles1 and  the geological    
changes which have affected their area1 
especially during  the epoch of the     
,northern drift1 to which reference has 
already been  made1 he put forth a most 
pregnant suggestion4    ,in certain     
parts of the sea bottom in the immediate
 vicinity of the  ,british ,islands1 as 
in the ,clyde district1 among the       
,hebrides1 in the  ,moray ,firth1 and in
 the ,german ,ocean1 there are depressed
 areas1 forming a  kind of submarine    
valleys1 the centres of which are from  
#hj to #ajj  fathoms1 or more1 deep4    
,these depressions are inhabited by     
assemblages of  marine animals1 which   

differ from those found over the        
adjacent and  shallower region1 and     
resemble those which are met with much  
farther  north1 on the ,norwegian coast4
 ,forbes called these ,scandinavian     
detachments ,northern outliers4    ,how 
did these isolated patches of a northern
 population get into these  deep places8
 ,to explain the mystery1 ,forbes called
 to mind the fact that1  in the epoch   
which immediately preceded the present1 
the climate was much  colder 7whence the
 name of glacial epoch applied to it72  
and that the  shells which are found    
fossil1 or sub-fossil1 in deposits of   
that age are  precisely such as are now 
to be met with only in the              
,scandinavian1 or  still more ,arctic1  
regions4 ,undoubtedly1 during the       
glacial epoch1 the  general population  
of our seas had1 universally1 the       
northern aspect  which is now presented 
only by the northern outliers2 just as  
the  vegetation of the land1 down to the
 sea-level1 had the northern character  

which is1 at present1 exhibited only by 
the plants which live on the tops  of   
our mountains4 ,but1 as the glacial     
epoch passed away1 and the present      
climatal conditions were developed1 the 
northern plants were able to  maintain  
themselves only on the bleak heights1 on
 which southern forms  could not compete
 with them4 ,and1 in like manner1       
,forbes suggested that1  after the      
glacial epoch1 the northern animals then
 inhabiting the sea  became restricted  
to the deeps in which they could hold   
their own against  invaders from the    
south1 better fitted than they to       
flourish in the  warmer waters of the   
shallows4 ,thus depth in the sea        
corresponded in its  effect upon        
distribution to height on the land4     
,the same idea is applied to the        
explanation of a similar anomaly in the 
,fauna of the ,aegean3--    ,in the     
deepest of the regions of depth of the  
,aegean1 the representation  of a       
,northern ,fauna is maintained1 partly  

by identical and partly by              
representative forms4444 ,the presence  
of the latter is essentially due to  the
 law 7of representation of parallels of 
latitude by zones of depth71  whilst    
that of the former species depended on  
their transmission from  their parent   
seas during a former epoch1 and         
subsequent isolation4 ,that  epoch was  
doubtless the newer ,pliocene or        
,glacial ,era1 when the ,mya  truncata  
and other northern forms now extinct in 
the ,mediterranean1 and  found fossil in
 the ,sicilian tertiaries1 ranged into  
that sea4 ,the  changes which there     
destroyed the shallow water glacial     
forms1 did not  affect those living in  
the depths1 and which still survive4#f  
,footnote #f3 ,memoirs of the           
,geological ,survey of ,great ,britain1 
,vol4 i4  p4 #cij4    ,the conception   
that the inhabitants of local           
depressions of the sea  bottom might be 
a remnant of the ancient population of  
the area1 which  had held their own in  

these deep fastnesses against an        
invading ,fauna1 as  ,britons and ,gaels
 have held out in ,wales and in         
,scotland against  encroaching ,teutons1
 thus broached by ,forbes1 received a   
wider  application than ,forbes had     
dreamed of when the sounding machine    
first  brought up specimens of the mud  
of the deep sea4 ,as ,i have pointed out
  elsewhere1#g it at once became obvious
 that the calcareous sticky mud of  the 
,atlantic was made up1 in the main1 of  
shells of ,globigerina and  other       
,foraminifera1 identical with those of  
which the true chalk is  composed1 and  
the identity extended even to the       
presence of those  singular bodies1 the 
,coccoliths and ,coccospheres1 the true 
nature of  which is not yet made out4   
,here then were organisms1 as old as the
  cretaceous epoch1 still alive1 and    
doing their work of rock-making at the  
bottom of existing seas4 ,what if       
,globigerina and the ,coccoliths should 
not be the only survivors of a world    

passed away1 which are hidden  beneath  
three miles of salt water8 ,the letter  
which ,dr4 ,wyville ,thomson  wrote to  
,dr4 ,carpenter in ,may1 #ahfh1 out of  
which all these expeditions  have grown1
 shows that this query had become a     
practical problem in ,dr4  ,thomson's   
mind at that time2 and the desirableness
 of solving the problem  is put in the  
foreground of his reasons for urging the
 ,government to  undertake the work of  
exploration3--    ,footnote #g3 ,see    
above1 ,on a ,piece of ,chalk1 p4 #ac4  
,two years ago1 ,m4 ,sars1 ,swedish     
,government ,inspector of ,fisheries1   
had  an opportunity1 in his official    
capacity1 of dredging off the ,loffoten 
,islands at a depth of #cjj fathoms4 ,i 
visited ,norway shortly after his       
return1 and had an opportunity of       
studying with his father1 ,professor    
,sars1 some of his results4 ,animal     
forms were abundant2 many of them  were 
new to science2 and among them was one  
of surpassing interest1 the  small      

crinoid1 of which you have a specimen1  
and which we at once  recognised as a   
degraded type of the ,apiocrinidoe1 an  
order hitherto  regarded as extinct1    
which attained its maximum in the ,pear 
,encrinites of  the ,jurassic period1   
and whose latest representative hitherto
 known was  the ,bourguettocrinus of the
 chalk4 ,some years previously1 ,mr4    
,absjornsen1 dredging in #bjj fathoms in
 the ,hardangerfjord1 procured  several 
examples of a ,starfish 7,brisinga71    
which seems to find its  nearest ally in
 the fossil genus ,protaster4 ,these    
observations place it  beyond a doubt   
that animal life is abundant in the     
ocean at depths  varying from #bjj to   
#cjj fathoms1 that the forms at these   
great depths  differ greatly from those 
met with in ordinary dredgings1 and     
that1 at  all events in some cases1     
these animals are closely allied to1 and
 would  seem to be directly descended   
from1 the ,fauna of the early           
tertiaries4    ,i think the latter      

result might almost have been           
anticipated2 and1  probably1 further    
investigation will largely add to this  
class of data1  and will give us an     
opportunity of testing our              
determinations of the  zoological       
position of some fossil types by an     
examination of the soft  parts of their 
recent representatives4 ,the main cause 
of the destruction1  the migration1 and 
the extreme modification of animal      
types1 appear to be  change of climate1 
chiefly depending upon oscillations of  
the earth's  crust4 ,these oscillations 
do not appear to have ranged1 in the    
,northern  portion of the ,northern     
,hemisphere1 much beyond #a1jjj feet    
since the  commencement of the ,tertiary
 ,epoch4 ,the temperature of deep waters
 seems  to be constant for all latitudes
 at #ci2 so that an immense area of the 
,north ,atlantic must have had its      
conditions unaffected by tertiary or    
post-tertiary oscillations4#h           
,footnote #h3 ,the ,depths of the ,sea1 

pp4 #ea-eb4    ,as we shall see1 the    
assumption that the temperature of the  
deep sea is  everywhere #ci ,f4 7#d     
,cent47 is an error1 which ,dr4 ,wyville
 ,thomson  adopted from eminent physical
 writers2 but the general justice of the
  reasoning is not affected by this     
circumstance1 and ,dr4 ,thomson's       
expectation has been1 to some extent1   
already verified4    ,thus besides      
,globigerina1 there are eighteen species
 of deep-sea  ,foraminifera identical   
with species found in the chalk4        
,imbedded in the  chalky mud of the deep
 sea1 in many localities1 are           
innumerable cup-  shaped sponges1       
provided with six-rayed silicious       
spicula1 so disposed  that the wall of  
the cup is formed of a lacework of      
flinty thread4 ,not  less abundant1 in  
some parts of the chalk formation1 are  
the fossils  known as ,ventriculites1   
well described by ,dr4 ,thomson as      
elegant vases  or cups1 with branching  
root-like bases1 or groups of regularly 

or  irregularly spreading tubes         
delicately fretted on the surface with  
an  impressed network like the finest   
lace2 and he adds1 ,when we compare     
such recent forms as ,aphrocallistes1   
,iphiteon1 ,holtenia1 and  ,askonema1   
with certain series of the chalk        
,ventriculites1 there  cannot be the    
slightest doubt that they belong to the 
same family--in  some cases to very     
nearly allied genera4#i    ,footnote #i3
 ,the ,depths of the ,sea1 p4 #dhd4     
,professor ,duncan finds several corals 
from the coast of ,portugal more  nearly
 allied to chalk forms than to any      
others4    ,the ,stalked ,crinoids or   
,feather ,stars1 so abundant in ancient 
times1 are  now exclusively confined to 
the deep sea1 and the late explorations 
have  yielded forms of old affinity1 the
 existence of which has hitherto been   
unsuspected4 ,the general character of  
the group of star fishes imbedded  in   
the white chalk is almost the same as in
 the modern ,fauna of the deep          

,atlantic4 ,the sea urchins of the deep 
sea1 while none of them are             
specifically identical with any chalk   
form1 belong to the same general        
groups1 and some closely approach       
extinct cretaceous genera4    ,taking   
these facts in conjunction with the     
positive evidence of the  existence1    
during the ,cretaceous epoch1 of a deep 
ocean where now lies  the dry land of   
central and southern ,europe1 northern  
,africa1 and western  and southern      
,asia2 and of the gradual diminution of 
this ocean during the  older tertiary   
epoch1 until it is represented at the   
present day by such  teacupfuls as the  
,caspian1 the ,black ,sea1 and the      
,mediterranean2 the  supposition of ,dr4
 ,thomson and ,dr4 ,carpenter that what 
is now the deep  ,atlantic1 was the deep
 ,atlantic 7though merged in a vast     
easterly  extension7 in the ,cretaceous 
epoch1 and that the ,globigerina mud has
  been accumulating there from that time
 to this1 seems to me to have a  great  

degree of probability4 ,and ,i agree    
with ,dr4 ,wyville ,thomson against     
,sir ,charles ,lyell 7it takes two of us
 to have any chance against his         
authority7 in demurring to the assertion
 that to talk of chalk having  been     
uninterruptedly formed in the ,atlantic 
is as inadmissible in a  geographical as
 in a geological sense4    ,if the word 
chalk is to be used as a stratigraphical
 term and  restricted to ,globigerina   
mud deposited during the ,cretaceous    
epoch1 of  course it is improper to call
 the precisely similar mud of more      
recent  date1 chalk4 ,if1 on the other  
hand1 it is to be used as a             
mineralogical  term1 ,i do not see how  
the modern and the ancient chalks are to
 be  separated--and1 looking at the     
matter geographically1 ,i see no reason 
to  doubt that a boring rod driven from 
the surface of the mud which forms  the 
floor of the mid-,atlantic would pass   
through one continuous mass of          
,globigerina mud1 first of modern1 then 

of tertiary1 and then of  mesozoic date2
 the chalks of different depths and ages
 being  distinguished merely by the     
different forms of other organisms      
associated  with the ,globigerinoe4     
,on the other hand1 ,i think it must be 
admitted that a belief in the           
continuity of the modern with the       
ancient chalk has nothing to do with    
the proposition that we can1 in any     
sense whatever1 be said to be still     
living in the ,cretaceous epoch4 ,when  
the ,challenger's trawl brings up  an   
,ichthyosaurus1 along with a few living 
specimens of ,belemnites and            
,turrilites1 it may be admitted that she
 has come upon a cretaceous  outlier4 ,a
 geological period is characterized not 
only by the presence  of those creatures
 which lived in it1 but by the absence  
of those which  have only come into     
existence later2 and1 however large a   
proportion of  true cretaceous forms may
 be discovered in the deep sea1 the     
modern types  associated with them must 

be abolished before the ,fauna1 as a    
whole1  could1 with any propriety1 be   
termed ,cretaceous4      ,i have now    
indicated some of the chief lines of    
,biological inquiry1 in  which the      
,challenger has special opportunities   
for doing good service1  and in         
following which she will be carrying out
 the work already  commenced by the     
,lightning and ,porcupine in their      
cruises of #ahfh and  subsequent years4 
,but biology1 in the long run1 rests    
upon physics1 and the first condition   
for arriving at a sound theory of       
distribution in the deep sea1 is the    
precise ascertainment of the conditions 
of life2 or1 in other words1 a  full    
knowledge of all those phenomena which  
are embraced under the head  of the     
,physical ,geography of the ,ocean4     
,excellent work has already been done in
 this direction1 chiefly under the      
superintendence of ,dr4 ,carpenter1 by  
the ,lightning and the  ,porcupine1#aj  
and some data of fundamental importance 

to the physical  geography of the sea   
have been fixed beyond a doubt4         
,footnote #aj3 ,proceedings of the      
,royal ,society1 #ahgj and #ahgb        
,thus1 though it is true that sea-water 
steadily contracts as it cools  down to 
its freezing point1 instead of expanding
 before it reaches its  freezing point  
as fresh water does1 the truth has been 
steadily ignored  by even the highest   
authorities in physical geography1 and  
the erroneous  conclusions deduced from 
their erroneous premises have been      
widely  accepted as if they were        
ascertained facts4 ,of course1 if       
sea-water1 like  fresh water1 were      
heaviest at a temperature of #ci ,f4 and
 got lighter as  it approached #cb ,f41 
the water of the bottom of the deep sea 
could not  be colder than #ci4 ,but one 
of the first results of the careful     
ascertainment of the temperature at     
different depths1 by means of           
thermometers specially contrived for the
 avoidance of the errors produced  by   

pressure1 was the proof that1 below     
#ajjj fathoms in the ,atlantic1 down  to
 the greatest depths yet sounded1 the   
water has a temperature always  lower   
than #ch ,fahr41 whatever be the        
temperature of the water at the         
surface4 ,and that this low temperature 
of the deepest water is probably  the   
universal rule for the depths of the    
open ocean is shown1 among  others1 by  
,captain ,chimmo's recent observations  
in the ,indian ocean1  between ,ceylon  
and ,sumatra1 where1 the surface water  
ranging from #he-ha  ,fahr41 the        
temperature at the bottom1 at a depth of
 #bbgj to #bfef fathoms1  was only from 
#cd to #cb ,fahr4    ,as the mean       
temperature of the superficial layer of 
the crust of the  earth may be taken at 
about #ej ,fahr41 it follows that the   
bottom layer  of the deep sea in        
temperate and hot latitudes1 is1 on the 
average1 much  colder than either of the
 bodies with which it is in contact2 for
 the  temperature of the earth is       

constant1 while that of the air rarely  
falls  so low as that of the bottom     
water in the latitudes in question2 and 
even  when it does1 has time to affect  
only a comparatively thin stratum of the
  surface water before the return of    
warm weather4    ,how does this         
apparently anomalous state of things    
come about8 ,if we  suppose the globe to
 be covered with a universal ocean1 it  
can hardly be  doubted that the cold of 
the regions towards the poles must tend 
to cause  the superficial water of those
 regions to contract and become         
specifically heavier4 ,under these      
circumstances1 it would have no         
alternative but to descend and spread   
over the sea bottom1 while its  place   
would be taken by warmer water drawn    
from the adjacent regions4  ,thus1 deep1
 cold1 polar-equatorial currents1 and   
superficial1 warmer1  equatorial-polar  
currents1 would be set up2 and as the   
former would have  a less velocity of   
rotation from west to east than the     

regions towards  which they travel1 they
 would not be due southerly or northerly
 currents1  but south-westerly in the   
northern hemisphere1 and north-westerly 
in the  southern2 while1 by a parity of 
reasoning1 the equatorial-polar warm    
currents would be north-easterly in the 
northern hemisphere1 and south-         
easterly in the southern4 ,hence1 as a  
north-easterly current has the same     
direction as a south-westerly wind1 the 
direction of the northern               
equatorial-polar current in the         
extra-tropical part of its course would 
pretty nearly coincide with that of the 
anti-trade winds4 ,the freezing of  the 
surface of the polar sea would not      
interfere with the movement thus  set   
up4 ,for1 however bad a conductor of    
heat ice may be1 the unfrozen  sea-water
 immediately in contact with the        
undersurface of the ice must  needs be  
colder than that further off2 and hence 
will constantly tend to  descend through
 the subjacent warmer water4    ,in this

 way1 it would seem inevitable that the 
surface waters of the  northern and     
southern frigid zones must1 sooner or   
later1 find their way  to the bottom of 
the rest of the ocean2 and there        
accumulate to a  thickness dependent on 
the rate at which they absorb heat from 
the crust  of the earth below1 and from 
the surface water above4    ,if this    
hypothesis be correct1 it follows that1 
if any part of the ocean  in warm       
latitudes is shut off from the influence
 of the cold polar  underflow1 the      
temperature of its deeps should be less 
cold than the  temperature of           
corresponding depths in the open sea4   
,now1 in the  ,mediterranean1 ,nature   
offers a remarkable experimental proof  
of just the  kind needed4 ,it is a      
landlocked sea which runs nearly east   
and west1  between the twenty-ninth and 
forty-fifth parallels of north latitude4
  ,roughly speaking1 the average        
temperature of the air over it is #ge   
,fahr4  in ,july and #dh in ,january4   

,this great expanse of water is divided 
by the peninsula of ,italy  7including  
,sicily71 continuous with which is a    
submarine elevation  carrying less than 
#a1bjj feet of water1 which extends from
 ,sicily to ,cape  ,bon in ,africa1 into
 two great pools--an eastern and a      
western4 ,the  eastern pool rapidly     
deepens to more than #ab1jjj feet1 and  
sends off to  the north its             
comparatively shallow branches1 the     
,adriatic and the ,aegean  ,seas4 ,the  
western pool is less deep1 though it    
reaches some #aj1jjj feet4  ,and1 just  
as the western end of the eastern pool  
communicates by a  shallow passage1 not 
a sixth of its greatest depth1 with the 
western  pool1 so the western pool is   
separated from the ,atlantic by a ridge 
which  runs between ,capes ,trafalgar   
and ,spartel1 on which there is hardly  
#a1jjj  feet of water4 ,all the water of
 the ,mediterranean which lies deeper   
than  about #aej fathoms1 therefore1 is 
shut off from that of the ,atlantic1 and

  there is no communication between the 
cold layer of the ,atlantic 7below      
#a1jjj fathoms7 and the ,mediterranean4 
,under these circumstances1 what is  the
 temperature of the ,mediterranean8     
,everywhere below #fjj feet it is  about
 #ee ,fahr42 and consequently1 at its   
greatest depths1 it is some #bj  warmer 
than the corresponding depths of the    
,atlantic4    ,it seems extremely       
difficult to account for this difference
 in any other  way1 than by adopting the
 views so strongly and ably advocated by
 ,dr4  ,carpenter1 that1 in the existing
 distribution of land and water1 such a 
circulation of the water of the ocean   
does actually occur1 as  theoretically  
must occur1 in the universal ocean1 with
 which we started4    ,it is quite      
another question1 however1 whether this 
theoretic  circulation1 true cause as it
 may be1 is competent to give rise to   
such  movements of sea-water1 in mass1  
as those currents1 which have commonly  
been regarded as northern extensions of 

the ,gulf-stream4 ,i shall not  venture 
to touch upon this complicated problem2 
but ,i may take occasion  to remark that
 the cause of a much simpler            
phenomenon--the stream of  ,atlantic    
water which sets through the ,straits of
 ,gibraltar1 eastward1 at  the rate of  
two or three miles an hour or more1 does
 not seem to be so  clearly made out as 
is desirable4    ,the facts appear to be
 that the water of the ,mediterranean is
 very  slightly denser than that of the 
,atlantic 7#a4jbgh to #a4jbfe71 and that
  the deep water of the ,mediterranean  
is slightly denser than that of the     
surface2 while the deep water of the    
,atlantic is1 if anything1 lighter  than
 that of the surface4 ,moreover1 while a
 rapid superficial current is  setting  
in 7always1 save in exceptionally       
violent easterly winds7 through  the    
,straits of ,gibraltar1 from the        
,atlantic to the ,mediterranean1 a deep 
undercurrent 7together with variable    
side currents7 is setting out  through  

the ,straits1 from the ,mediterranean to
 the ,atlantic4    ,dr4 ,carpenter      
adopts1 without hesitation1 the view    
that the cause of this  indraught of    
,atlantic water is to be sought in the  
much more rapid  evaporation which takes
 place from the surface of the          
,mediterranean than  from that of the   
,atlantic2 and thus1 by lowering the    
level of the former1  gives rise to an  
indraught from the latter4    ,but is   
there any sound foundation for the three
 assumptions involved  here8 ,firstly1  
that the evaporation from the           
,mediterranean1 as a whole1  is much    
greater than that from the ,atlantic    
under corresponding  parallels2         
secondly1 that the rainfall over the    
,mediterranean makes up  for evaporation
 less than it does over the ,atlantic2  
and thirdly1  supposing these two       
questions answered affirmatively3 ,are  
not these  sources of loss in the       
,mediterranean fully covered by the     
prodigious  quantity of fresh water     

which is poured into it by great rivers 
and  submarine springs8 ,consider that  
the water of the ,ebro1 the ,rhine1 the 
,po1 the ,danube1 the ,don1 the         
,dnieper1 and the ,nile1 all flow       
directly or  indirectly into the        
,mediterranean2 that the volume of fresh
 water which  they pour into it is so   
enormous that fresh water may sometimes 
be baled  up from the surface of the sea
 off the ,delta of the ,nile1 while the 
land  is not yet in sight2 that the     
water of the ,black ,sea is half fresh1 
and  that a current of three or four    
miles an hour constantly streams from it
  ,mediterraneanwards through the       
,bosphorus2--consider1 in addition1 that
 no  fewer than ten submarine springs of
 fresh water are known to burst up in   
the ,mediterranean1 some of them so     
large that ,admiral ,smyth calls them   
subterranean rivers of amazing volume   
and force2 and it would seem1 on  the   
face of the matter1 that the sun must   
have enough to do to keep the  level of 

the ,mediterranean down2 and that1      
possibly1 we may have to seek  for the  
cause of the small superiority in saline
 contents of the  ,mediterranean water  
in some condition other than solar      
evaporation4    ,again1 if the          
,gibraltar indraught is the effect of   
evaporation1 why does  it go on in      
winter as well as in summer8    ,all    
these are questions more easily asked   
than answered2 but they must be         
answered before we can accept the       
,gibraltar stream as an example of a    
current produced by indraught with any  
comfort4    ,the ,mediterranean is not  
included in the ,challenger's route1 but
 she  will visit one of the most        
promising and little explored of        
hydrographical regions--the ,north      
,pacific1 between ,polynesia and the    
,asiatic and ,american shores2 and      
doubtless the store of observations upon
  the currents of this region1 which she
 will accumulate1 when compared  with   
what we know of the ,north ,atlantic1   

will throw a powerful light upon  the   
present obscurity of the ,gulf-stream   
problem4        ,,iii      ,,on ,,some  
,,of ,,the ,,results ,,of ,,the         
,,expedition ,,of ,h4,m4,s4             
,,challlenger    #ahge    ,in ,may1     
#ahgc1 ,i drew attention#a to the       
important problems connected  with the  
physics and natural history of the sea1 
to the solution of which  there was     
every reason to hope the cruise of      
,h4,m4,s4 ,challenger would  furnish    
important contributions4 ,the           
expectation then expressed has not  been
 disappointed4 ,reports to the          
,admiralty1 papers communicated to the  
,royal ,society1 and large collections  
which have already been sent home1  have
 shown that the ,challenger's staff have
 made admirable use of their  great     
opportunities2 and that1 on the return  
of the expedition in #ahgd1  their      
performance will be fully up to the     
level of their promise4 ,indeed1  ,i am 
disposed to go so far as to say1 that if

 nothing more came of the  ,challengers 
expedition than has hitherto been       
yielded by her  exploration of the      
nature of the sea bottom at great       
depths1 a full  scientific equivalent of
 the trouble and expense of her         
equipment would  have been obtained4    
,footnote #a3 ,see the preceding ,essay4
    ,in order to justify this assertion1
 and yet1 at the same time1 not to      
claim more for ,professor ,wyville      
,thomson and his colleagues than is     
their  due1 ,i must give a brief history
 of the observations which have preceded
  their exploration of this recondite   
field of research1 and endeavour to     
make clear what was the state of        
knowledge in ,december1 #ahgb1 and what 
new facts have been added by the        
scientific staff of the ,challenger4 ,so
  far as ,i have been able to discover1 
the first successful attempt to  bring  
up from great depths more of the sea    
bottom than would adhere to a           
sounding-lead1 was made by ,sir ,john   

,ross1 in the voyage to the ,arctic     
regions which he undertook in #ahah4 ,in
 the ,appendix to the narrative of  that
 voyage1 there will be found an account 
of a very ingenious apparatus  called   
clams--a sort of double scoop--of his   
own contrivance1 which ,sir  ,john ,ross
 had made by the ship's armourer2 and by
 which1 being in  ,baffin's ,bay1 in #gb
 #cj' ,n4 and #gg #ae' ,w41 he succeeded
 in bringing up  from #a1jej fathoms 7or
 #f1cjj feet71 several pounds of a fine 
green  mud1 which formed the bottom of  
the sea in this region4 ,captain 7now   
,sir  ,edward7 ,sabine1 who accompanied 
,sir ,john ,ross on this cruise1 says of
  this mud that it was soft and         
greenish1 and that the lead sunk several
  feet into it4 ,a similar fine green   
mud was found to compose the sea  bottom
 in ,davis ,straits by ,goodsir in      
#ahde4 ,nothing is certainly known of   
the exact nature of the mud thus        
obtained1 but we shall see that the mud 
of the bottom of the ,antarctic seas is 

described in curiously similar  terms by
 ,dr4 ,hooker1 and there is no doubt as 
to the composition of this  deposit4    
,in #ahej1 ,captain ,penny collected in 
,assistance ,bay1 in ,kingston ,bay1 and
  in ,melville ,bay1 which lie between  
#gc #de' and #gd #dj' ,n41 specimens of 
the residuum left by melted surface ice1
 and of the sea bottom in these         
localities4 ,dr4 ,dickie1 of ,aberdeen1 
sent these materials to ,ehrenberg1  who
 made out#b that the residuum of the    
melted ice consisted for the  most part 
of the silicious cases of diatomaceous  
plants1 and of the  silicious spicula of
 sponges2 while1 mixed with these1 were 
a certain  number of the equally        
silicious skeletons of those low animal 
organisms1  which were termed           
,polycistineoe by ,ehrenberg1 but are   
now known as  ,radiolaria4    ,footnote 
#b3 ,ueber neue ,anschauungen des       
kleinsten nrdlichen                     
,polarlebens4--,monatsberichte d4 ,k4   
,akad4 ,berlin1 #ahec4    ,in #ahef1 a  

very remarkable addition to our         
knowledge of the nature of the  sea     
bottom in high northern latitudes was   
made by ,professor ,bailey of  ,west    
,point4 ,lieutenant ,brooke1 of the     
,united ,states ,navy1 who was  employed
 in surveying the ,sea of ,kamschatka1  
had succeeded in obtaining  specimens of
 the sea bottom from greater depths than
 any hitherto  reached1 namely from     
#b1gjj fathoms 7#af1bjj feet7 in #ef    
#df' ,n41 and #afh  #ah' ,e42 and from  
#a1gjj fathoms 7#aj1bjj feet7 in #fj    
#ae' ,n4 and #agj #ec'  ,e4 ,on         
examining these microscopically1        
,professor ,bailey found1 as  ,ehrenberg
 had done in the case of mud obtained on
 the opposite side of  the ,arctic      
region1 that the fine mud was made up of
 shells of  ,diatomacoe1 of spicula of  
sponges1 and of ,radiolaria1 with a     
small  admixture of mineral matters1 but
 without a trace of any calcareous      
organisms4    ,still more complete      
information has been obtained concerning

 the nature  of the sea bottom in the   
cold zone around the south pole4        
,between the  years #ahci and #ahdc1    
,sir ,james ,clark ,ross executed his   
famous ,antarctic  expedition1 in the   
course of which he penetrated1 at two   
widely distant  points of the ,antarctic
 zone1 into the high latitudes of the   
shores of  ,victoria ,land and of       
,graham's ,land1 and reached the        
parallel of #hj ,s4  ,sir ,james ,ross  
was himself a naturalist of no mean     
acquirements1 and ,dr4  ,hooker1#c the  
present ,president of the ,royal        
,society1 accompanied him as  naturalist
 to the expedition1 so that the         
observations upon the fauna and  flora  
of the ,antarctic regions made during   
this cruise were sure to have  a        
peculiar value and importance1 even had 
not the attention of the  voyagers been 
particularly directed to the importance 
of noting the  occurrence of the        
minutest forms of animal and vegetable  
life in the  ocean4    ,footnote #c3    

,now ,sir ,joseph ,hooker4 #ahid4       
,among the scientific instructions for  
the voyage drawn up by a committee  of  
the ,royal ,society1 however1 there is a
 remarkable letter from ,von  ,humboldt 
to ,lord ,minto1 then ,first ,lord of   
the ,admiralty1 in which1 among  other  
things1 he dwells upon the significance 
of the researches into the  microscopic 
composition of rocks1 and the discovery 
of the great share  which microscopic   
organisms take in the formation of the  
crust of the  earth at the present day1 
made by ,ehrenberg in the years         
#ahcf-ci4  ,ehrenberg1 in fact1 had     
shown that the extensive beds of        
rotten-stone  or ,tripoli which occur in
 various parts of the world1 and notably
 at  ,bilin in ,bohemia1 consisted of   
accumulations of the silicious cases and
  skeletons of ,diatomaceoe1 sponges1   
and ,radiolaria2 he had proved that     
similar deposits were being formed by   
,diatomaceoe1 in the pools of the       
,thiergarten in ,berlin and elsewhere1  

and had pointed out that1 if it were    
commercially worth while1 rotten-stone  
might be manufactured by a process  of  
diatom-culture4 ,observations conducted 
at ,cuxhaven in #ahci1 had  revealed the
 existence1 at the surface of the waters
 of the ,baltic1 of  living ,diatoms and
 ,radiolaria of the same species as     
those which1 in a  fossil state1        
constitute extensive rocks of tertiary  
age at ,caltanisetta1  ,zante1 and      
,oran1 on the shores of the             
,mediterranean4    ,moreover1 in the    
fresh-water rotten-stone beds of ,bilin1
 ,ehrenberg had  traced out the         
metamorphosis1 effected apparently by   
the action of  percolating water1 of the
 primitively loose and friable deposit  
of  organized particles1 in which the   
silex exists in the hydrated or soluble 
condition4 ,the silex1 in fact1         
undergoes solution and slow             
redeposition1  until1 in ultimate       
result1 the excessively fine-grained    
sand1 each  particle of which is a      

skeleton1 becomes converted into a dense
 opaline  stone1 with only here and     
there an indication of an organism4     
,from the consideration of these facts1 
,ehrenberg1 as early as the year  #ahci1
 had arrived at the conclusion that     
rocks1 altogether similar to  those     
which constitute a large part of the    
crust of the earth1 must be  forming1 at
 the present day1 at the bottom of the  
sea2 and he threw out  the suggestion   
that even where no trace of organic     
structure is to be  found in the older  
rocks1 it may have been lost by         
metamorphosis4#d    ,footnote #d3 ,ueber
 die noch jetzt zahlreich lebende       
,thierarten der  ,kreidebildung und den 
,organismus der ,polythalamien4         
,abhandlungen der ,kn4  ,akad4 der      
,wissenchaften4 #ahci4 ,berlin4 #ahda4  
,i am afraid that this  remarkable paper
 has been somewhat overlooked in the    
recent discussions  of the relation of  
ancient rocks to modern deposits4       
,the results of the ,antarctic          

exploration1 as stated by ,dr4 ,hooker  
in the  ,botany of the ,antarctic       
,voyage1 and in a paper which he read   
before  the ,british ,association in    
#ahdg1 are of the greatest importance in
  connection with these views1 and they 
are so clearly stated in the former     
work1 which is somewhat inaccessible1   
that ,i make no apology for quoting     
them at length--    ,the waters and the 
ice of the ,south ,polar ,ocean were    
alike found to  abound with microscopic 
vegetables belonging to the order       
,diatomaceoe4  ,though much too small to
 be discernible by the naked eye1 they  
occurred  in such countless myriads as  
to stain the berg and the pack ice      
wherever  they were washed by the swell 
of the sea2 and1 when enclosed in the   
congealing surface of the water1 they   
imparted to the brash and pancake  ice a
 pale ochreous colour4 ,in the open     
ocean1 northward of the frozen  zone1   
this order1 though no doubt almost      
universally present1 generally  eludes  

the search of the naturalist2 except    
when its species are  congregated       
amongst that mucous scum which is       
sometimes seen floating on  the waves1  
and of whose real nature we are         
ignorant2 or when the coloured  contents
 of the marine animals who feed on these
 ,algae are examined4 ,to  the south1   
however1 of the belt of ice which       
encircles the globe1 between  the       
parallels of #ej and #gj ,s41 and in the
 waters comprised between that  belt and
 the highest latitude ever attained by  
man1 this vegetation is  very           
conspicuous1 from the contrast between  
its colour and the white snow  and ice  
in which it is imbedded4 ,insomuch1 that
 in the eightieth degree1  all the      
surface ice carried along by the        
currents1 the sides of every  berg and  
the base of the great ,victoria ,barrier
 itself1 within reach of  the swell1    
were tinged brown1 as if the polar      
waters were charged with  oxide of iron4
    ,as the majority of these plants    

consist of very simple vegetable cells1 
enclosed in indestructible silex 7as    
other ,algae are in carbonate of  lime71
 it is obvious that the death and       
decomposition of such multitudes  must  
form sedimentary deposits1 proportionate
 in their extent to the  length and     
exposure of the coast against which they
 are washed1 in  thickness to the power 
of such agents as the winds1 currents1  
and sea1  which sweep them more         
energetically to certain positions1 and 
in purity1  to the depth of the water   
and nature of the bottom4 ,hence we     
detected  their remains along every     
icebound shore1 in the depths of the    
adjacent  ocean1 between #hj and #djj   
fathoms4 ,off ,victoria ,barrier 7a     
perpendicular  wall of ice between one  
and two hundred feet above the level of 
the sea7  the bottom of the ocean was   
covered with a stratum of pure white or 
green  mud1 composed principally of the 
silicious shells of the ,diatomaceoe4   
,these1 on being put into water1        

rendered it cloudy like milk1 and took  
many hours to subside4 ,in the very deep
 water off ,victoria and ,graham's      
,land1 this mud was particularly pure   
and fine2 but towards the shallow       
shores there existed a greater or less  
admixture of disintegrated rock  and    
sand2 so that the organic compounds of  
the bottom frequently bore but  a small 
proportion to the inorganic4 444    ,the
 universal existence of such an         
invisible vegetation as that of the     
,antarctic ,ocean1 is a truly wonderful 
fact1 and the more from its not  being  
accompanied by plants of a high order4  
,during the years we spent  there1 ,i   
had been accustomed to regard the       
phenomena of life as differing  totally 
from what obtains throughout all other  
latitudes1 for everything  living       
appeared to be of animal origin4 ,the   
ocean swarmed with  ,mollusca1 and      
particularly entomostracous ,crustacea1 
small whales1  and porpoises2 the sea   
abounded with penguins and seals1 and   

the air with  birds2 the animal kingdom 
was ever present1 the larger creatures  
preying  on the smaller1 and these again
 on smaller still2 all seemed           
carnivorous4  ,the herbivorous were not 
recognised1 because feeding on a        
microscopic  herbage1 of whose true     
nature ,i had formed an erroneous       
impression4 ,it  is1 therefore1 with no 
little satisfaction that ,i now class   
the  ,diatomaceoe with plants1 probably 
maintaining in the ,south ,polar ,ocean 
that balance between the vegetable and  
the animal kingdoms which prevails  over
 the surface of our globe4 ,nor is the  
sustenance and nutrition of the  animal 
kingdom the only function these minute  
productions may perform2  they may also 
be the purifiers of the vitiated        
atmosphere1 and thus  execute in the    
,antarctic latitudes the office of our  
trees and grass turf  in the temperate  
regions1 and the broad leaves of the    
palm1 c41 in the  tropics4 444    ,with 
respect to the distribution of the      

,diatomaceoe1 ,dr4 ,hooker  remarks3--  
,there is probably no latitude between  
that of ,spitzbergen and ,victoria      
,land1 where some of the species of     
either country do not exist3 ,iceland1  
,britain1 the ,mediterranean ,sea1      
,north and ,south ,america1 and the     
,south  ,sea ,islands1 all possess      
,antarctic ,diatomaceoe4 ,the silicious 
coats of  species only known living in  
the waters of the ,south ,polar ,ocean1 
have1  during past ages1 contributed to 
the formation of rocks2 and thus they   
outlive several successive creations of 
organized beings4 ,the phonolite  stones
 of the ,rhine1 and the ,tripoli stone1 
contain species identical  with what are
 now contributing to form a sedimentary 
deposit 7and  perhaps1 at some future   
period1 a bed of rock7 extending in one 
continuous stratum for #djj measured    
miles4 ,i allude to the shores of the   
,victoria ,barrier1 along whose coast   
the soundings examined were  invariably 
charged with diatomaceous remains1      

constituting a bank which  stretches    
#bjj miles north from the base of       
,victoria ,barrier1 while the  average  
depth of water above it is #cjj fathoms1
 or #a1hjj feet4 ,again1  some of the   
,antarctic species have been detected   
floating in the  atmosphere which       
overhangs the wide ocean between ,africa
 and ,america4 ,the  knowledge of this  
marvellous fact we owe to ,mr4 ,darwin1 
who1 when he was  at sea off the ,cape  
de ,verd ,islands1 collected an         
impalpable powder which  fell on        
,captain ,fitzroy's ship4 ,he           
transmitted this dust to ,ehrenberg1    
who ascertained it to consist of the    
silicious coats1 chiefly of ,american   
,diatomaceoe1 which were being wafted   
through the upper region of the  air1   
when some meteorological phenomena      
checked them in their course and        
deposited them on the ship and surface  
of the ocean4    ,the existence of the  
remains of many species of this order   
7and amongst  them some ,antarctic ones7

 in the volcanic ashes1 pumice1 and     
scoriae of  active and extinct volcanoes
 7those of the ,mediterranean ,sea and  
,ascension ,island1 for instance7 is a  
fact bearing immediately upon the       
present subject4 ,mount ,erebus1 a      
volcano #ab1djj feet high1 of the first 
class in dimensions and energetic       
action1 rises at once from the ocean in 
the seventy-eighth degree of south      
latitude1 and abreast of the            
,diatomaceoe bank1 which reposes in part
 on its base4 ,hence it may not  appear 
preposterous to conclude that1 as       
,vesuvius receives the waters of  the   
,mediterranean1 with its fish1 to eject 
them by its crater1 so the  subterranean
 and subaqueous forces which maintain   
,mount ,erebus in  activity may         
occasionally receive organic matter from
 the bank1 and  disgorge it1 together   
with those volcanic products1 ashes and 
pumice4    ,along the shores of         
,graham's ,land and the ,south ,shetland
 ,islands1 we  have a parallel          

combination of igneous and aqueous      
action1 accompanied  with an equally    
copious supply of ,diatomaceoe4 ,in the 
,gulf of ,erebus  and ,terror1 fifteen  
degrees north of ,victoria ,land1 and   
placed on the  opposite side of the     
globe1 the soundings were of a similar  
nature with  those of the ,victoria     
,land and ,barrier1 and the sea and ice 
as full of  ,diatomaceoe4 ,this was not 
only proved by the deep sea lead1 but by
 the  examination of bergs which1 once  
stranded1 had floated off and become    
reversed1 exposing an accumulation of   
white friable mud frozen to their       
bases1 which abounded with these        
vegetable remains4    ,the ,challenger  
has explored the ,antarctic seas in a   
region intermediate  between those      
examined by ,sir ,james ,ross's         
expedition2 and the  observations made  
by ,dr4 ,wyville ,thomson and his       
colleagues in every  respect confirm    
those of ,dr4 ,hooker3--    ,on the     
#aath of ,february1 lat4 #fj #eb' ,s41  

long4 #hj #bj' ,e41 and ,march #c1  lat4
 #ec #ee' ,s41 long4 #ajh #ce' ,e41 the 
sounding instrument came up  filled with
 a very fine cream-coloured paste1 which
 scarcely effervesced  with acid1 and   
dried into a very light1 impalpable1    
white powder4 ,this1  when examined     
under the microscope1 was found to      
consist almost entirely  of the         
frustules of ,diatoms1 some of them     
wonderfully perfect in all the  details 
of their ornament1 and many of them     
broken up4 ,the species of  ,diatoms    
entering into this deposit have not yet 
been worked up1 but they  appear to be  
referable chiefly to the genera         
,fragillaria1 ,coscinodiscus1           
,choetoceros1 ,asteromphalus1 and       
,dictyocha1 with fragments of the       
separated rods of a singular silicious  
organism1 with which we were            
unacquainted1 and which made up a large 
proportion of the finer matter of  this 
deposit4 ,mixed with the ,diatoms there 
were a few small  ,globigerinoe1 some of

 the tests and spicules of              
,radiolarians1 and some  sand particles2
 but these foreign bodies were in too   
small proportion to  affect the         
formation as consisting practically of  
,diatoms alone4 ,on the  #dth of        
,february1 in lat4 #eb1 #bi' ,s41 long41
 #ga #cf ,e41 a little to the  north of 
the ,heard ,islands1 the tow-net1       
dragging a few fathoms below the        
surface1 came up nearly filled with a   
pale yellow gelatinous mass4 ,this  was 
found to consist entirely of ,diatoms of
 the same species as those  found at the
 bottom4 ,by far the most abundant was  
the little bundle of  silicious rods1   
fastened together loosely at one end1   
separating from one  another at the     
other end1 and the whole bundle loosely 
twisted into a  spindle4 ,the rods are  
hollow1 and contain the characteristic  
endochrome  of the ,diatomaceoe4 ,like  
the ,globigerina ooze1 then1 which it   
succeeds to the southward in a band     
apparently of no great width1 the       

materials of this silicious deposit are 
derived entirely from the surface  and  
intermediate depths4 ,it is somewhat    
singular that ,diatoms did not  appear  
to be in such large numbers on the      
surface over the ,diatom ooze as  they  
were a little further north4 ,this may  
perhaps be accounted for by  our not    
having struck their belt of depth with  
the tow-net2 or it is  possible that    
when we found it on the #aath of        
,february the bottom deposit  was really
 shifted a little to the south by the   
warm current1 the  excessively fine     
flocculent dbris of the ,diatoms taking 
a certain time  to sink4 ,the belt of   
,diatom ooze is certainly a little      
further to the  southward in long4 #hc  
,e41 in the path of the reflux of the   
,agulhas  current1 than in long4 #ajh   
,e4    ,all along the edge of the       
ice-pack--everywhere1 in fact1 to the   
south of  the two stations--on the #aath
 of ,february on our southward voyage1  
and on  the #crd of ,march on our       

return1 we brought up fine sand and     
grayish mud1  with small pebbles of     
quartz and felspar1 and small fragments 
of mica-  slate1 chlorite-slate1        
clay-slate1 gneiss1 and granite4 ,this  
deposit1 ,i  have no doubt1 was derived 
from the surface like the others1 but in
 this  case by the melting of icebergs  
and the precipitation of foreign matter 
contained in the ice4    ,we never saw  
any trace of gravel or sand1 or any     
material necessarily  derived from land1
 on an iceberg4 ,several showed vertical
 or irregular  fissures filled with     
discoloured ice or snow2 but1 when      
looked at  closely1 the discoloration   
proved usually to be very slight1 and   
the  effect at a distance was usually   
due to the foreign material filling the 
fissure reflecting light less perfectly 
than the general surface of the  berg4  
,i conceive that the upper surface of   
one of these great tabular  southern    
icebergs1 including by far the greater  
part of its bulk1 and  culminating in   

the portion exposed above the surface of
 the sea1 was  formed by the piling up  
of successive layers of snow during the 
period1  amounting perhaps to several   
centuries1 during which the ice-cap was 
slowly forcing itself over the low land 
and out to sea over a long extent  of   
gentle slope1 until it reached a depth  
considerably above #bjj fathoms1  when  
the lower specific weight of the ice    
caused an upward strain which  at length
 overcame the cohesion of the mass1 and 
portions were rent off  and floated     
away4 ,if this be the true history of   
the formation of these  icebergs1 the   
absence of all land dbris in the portion
 exposed above  the surface of the sea  
is readily understood4 ,if any such     
exist1 it must  be confined to the lower
 part of the berg1 to that part which   
has at one  time or other moved on the  
floor of the ice-cap4    ,the icebergs1 
when they are first dispersed1 float in 
from #bjj to #bej  fathoms4 ,when1      
therefore1 they have been drifted to    

latitudes of #fe or  #fd ,s41 the bottom
 of the berg just reaches the layer at  
which the  temperature of the water is  
distinctly rising1 and it is rapidly    
melted1  and the mud and pebbles with   
which it is more or less charged are    
precipitated4 ,that this precipitation  
takes place all over the area where  the
 icebergs are breaking up1 constantly1  
and to a considerable extent1  is       
evident from the fact of the soundings  
being entirely composed of such         
deposits2 for the ,diatoms1             
,globigerinoe1 and radiolarians are     
present  on the surface in large        
numbers2 and unless the deposit from the
 ice were  abundant it would soon be    
covered and masked by a layer of the    
exuvia of  surface organisms4    ,the   
observations which have been detailed   
leave no doubt that the  ,antarctic sea 
bottom1 from a little to the south of   
the fiftieth  parallel1 as far as #hj   
,s41 is being covered by a fine deposit 
of  silicious mud1 more or less mixed1  

in some parts1 with the ice-borne  dbris
 of polar lands and with the ejections  
of volcanoes4 ,the  silicious particles 
which constitute this mud1 are derived1 
in part1 from  the diatomaceous plants  
and radiolarian animals which throng the
 surface1  and1 in part1 from the       
spicula of sponges which live at the    
bottom4 ,the  evidence respecting the   
corresponding ,arctic area is less      
complete1 but  it is sufficient to      
justify the conclusion that an          
essentially similar  silicious cap is   
being formed around the northern pole4  
,there is no doubt that the constituent 
particles of this mud may  agglomerate  
into a dense rock1 such as that formed  
at ,oran on the shores  of the          
,mediterranean1 which is made up of     
similar materials4 ,moreover1 in  the   
case of freshwater deposits of this kind
 it is certain that the  action of      
percolating water may convert the       
originally soft and friable1            
fine-grained sandstone into a dense1    

semi-transparent opaline stone1 the     
silicious organized skeletons being     
dissolved1 and the silex re-deposited   
in an amorphous state4 ,whether such a  
metamorphosis as this occurs in         
submarine deposits1 as well as in those 
formed in fresh water1 does not  appear2
 but there seems no reason to doubt that
 it may4 ,and hence it may  not be      
hazardous to conclude that very ordinary
 metamorphic agencies may  convert these
 polar caps into a form of quartzite4   
,in the great intermediate zone1        
occupying some #aaj of latitude1 which  
separates the circumpolar ,arctic and   
,antarctic areas of silicious  deposit1 
the ,diatoms and ,radiolaria of the     
surface water and the  sponges of the   
bottom do not die out1 and1 so far as   
some forms are  concerned1 do not even  
appear to diminish in total number2     
though1 on a  rough estimate1 it would  
appear that the proportion of           
,radiolaria to  ,diatoms is much greater
 than in the colder seas4 ,nevertheless 

the  composition of the deep-sea mud of 
this intermediate zone is entirely      
different from that of the circumpolar  
regions4    ,the first exact information
 respecting the nature of this mud at   
depths  greater than #a1jjj fathoms was 
given by ,ehrenberg1 in the account     
which  he published in the              
,monatsberichte of the ,berlin ,academy 
for the year  #ahec1 of the soundings   
obtained by ,lieut4 ,berryman1 of the   
,united ,states  ,navy1 in the ,north   
,atlantic1 between ,newfoundland and the
 ,azores4    ,observations which confirm
 those of ,ehrenberg in all essential   
respects  have been made by ,professor  
,bailey1 myself1 ,dr4 ,wallich1 ,dr4    
,carpenter1  and ,professor ,wyville    
,thomson1 in their earlier cruises2 and 
the  continuation of the ,globigerina   
ooze over the ,south ,pacific has been  
proved by the recent work of the        
,challenger1 by which it is also shown1 
for the first time1 that1 in passing    
from the equator to high southern       

latitudes1 the number and variety of the
 ,foraminifera diminishes1 and  even the
 ,globigerinoe become dwarfed4 ,and this
 result1 it will be  observed1 is in    
entire accordance with the fact already 
mentioned that1  in the sea of          
,kamschatka1 the deep-sea mud was found 
by ,bailey to contain  no calcareous    
organisms4    ,thus1 in the whole of the
 intermediate zone1 the silicious       
deposit  which is being formed there1 as
 elsewhere1 by the accumulation of      
sponge-  spicula1 ,radiolaria1 and      
,diatoms1 is obscured and overpowered by
 the  immensely greater amount of       
calcareous sediment1 which arises from  
the  aggregation of the skeletons of    
dead ,foraminifera4 ,the similarity of  
the deposit1 thus composed of a large   
percentage of carbonate of lime1  and a 
small percentage of silex1 to chalk1    
regarded merely as a kind of  rock1     
which was first pointed out by          
,ehrenberg1#e is now admitted on all    
hands2 nor can it be reasonably doubted1

 that ordinary metamorphic  agencies are
 competent to convert the modern chalk  
into hard limestone  or even into       
crystalline marble4    ,footnote #e3    
,the following passages in ,ehrenberg's 
memoir on ,the  ,organisms in the ,chalk
 which are still living 7#ahci71 are    
conclusive3--    #g4 ,the dawning period
 of the existing living organic         
creation1 if such a  period is          
distinguishable 7which is doubtful71 can
 only be supposed to  have existed on   
the other side of1 and below1 the chalk 
formation2 and  thus1 either the chalk1 
with its widespread and thick beds1 must
 enter  into the series of newer        
formations2 or some of the accepted four
 great  geological periods1 the         
quaternary1 tertiary1 and secondary     
formations1  contain organisms which    
still live4 ,it is more probable1 in the
  proportion of #c to #a1 that the      
transition or primary period is not     
different1 but that it is only more     
difficult to examine and understand1  by

 reason of the gradual and prolonged    
chemical decomposition and              
metamorphosis of many of its organic    
constituents4    #aj4 ,by the           
mass-forming ,infasoria and             
,polythalamia1 secondary are  not       
distinguishable from tertiary           
formations2 and1 from what has been     
said1 it is possible that1 at this very 
day1 rock masses are forming in  the    
sea1 and being raised by volcanic       
agencies1 the constitution of  which1 on
 the whole1 is altogether similar to    
that of the chalk4 ,the  chalk remains  
distinguishable by its organic remains  
as a formation1 but  not as a kind of   
rock4    ,ehrenberg appears to have     
taken it for granted that the           
,globigerinoe  and other ,foraminifera  
which are found in the deep-sea mud1    
live at the  great depths in which their
 remains are found2 and he supports this
  opinion by producing evidence that the
 soft parts of these organisms are      
preserved1 and may be demonstrated by   

removing the calcareous matter with     
dilute acids4 ,in #aheg1 the evidence   
for and against this conclusion         
appeared to me to be insufficient to    
warrant a positive conclusion one  way  
or the other1 and ,i expressed myself in
 my report to the ,admiralty on         
,captain ,dayman's soundings in the     
following terms3--    ,when we consider 
the immense area over which this deposit
 is spread1 the  depth at which its     
formation is going on1 and its          
similarity to chalk1  and still more to 
such rocks as the marls of              
,caltanisetta1 the question1  whence are
 all these organisms derived8 becomes   
one of high scientific  interest4       
,three answers have suggested           
themselves3--    ,in accordance with the
 prevalent view of the limitation of    
life to  comparatively small depths1 it 
is imagined either3 #a1 that these      
organisms have drifted into their       
present position from shallower waters2 
or #b1 that they habitually live at the 

surface of the ocean1 and only  fall    
down into their present position4    #a4
 ,i conceive that the first supposition 
is negatived by the extremely  marked   
zoological peculiarity of the deep-sea  
fauna4    ,had the ,globigerinoe been   
drifted into their present position from
  shallow water1 we should find a very  
large proportion of the  characteristic 
inhabitants of shallow waters mixed with
 them1 and this  would the more         
certainly be the case1 as the large     
,globigerinoe1 so  abundant in the      
deep-sea soundings1 are1 in proportion  
to their size1  more solid and massive  
than almost any other ,foraminifera4    
,but the fact  is that the proportion of
 other ,foraminifera is exceedingly     
small1 nor  have ,i found as yet1 in the
 deep-sea deposits1 any such matters as 
fragments of molluscous shells1 of      
,echini1 c41 which abound in shallow    
waters1 and are quite as likely to be   
drifted as the heavy  ,globigerinoe4    
,again1 the relative proportions of     

young and fully formed  ,globigerinoe   
seem inconsistent with the notion that  
they have travelled  far4 ,and it seems 
difficult to imagine why1 had the       
deposit been  accumulated in this way1  
,coscinodisci should so almost entirely 
represent the ,diatomaceoe4    #b4 ,the 
second hypothesis is far more feasible1 
and is strongly supported  by the fact  
that many ,polycistineoe ,radiolaria and
 ,coscinodisci are  well known to live  
at the surface of the ocean4 ,mr4       
,macdonald1 ,assistant-  ,surgeon of    
,h4,m4,s4 ,herald1 now in the           
,south-,western ,pacific1 has lately    
sent home some very valuable            
observations on living forms of this    
kind1  met with in the stomachs of      
oceanic mollusks1 and therefore         
certainly  inhabitants of the           
superficial layer of the ocean4 ,but it 
is a singular  circumstance that only   
one of the forms figured by ,mr4        
,macdonald is at  all like a            
,globigerina1 and there are some        

peculiarities about even  this which    
make me greatly doubt its affinity with 
that genus4 ,the form1  indeed1 is not  
unlike that of a ,globigerina1 but it is
 provided with  long radiating          
processes1 of which ,i have never seen  
any trace in  ,globigerina4 ,did they   
exist1 they might explain what otherwise
 is a  great objection to this view1    
viz41 how is it conceivable that the    
heavy  ,globigerina should maintain     
itself at the surface of the water8     
,if the organic bodies in the deep-sea  
soundings have neither been  drifted1   
nor have fallen from above1 there       
remains but one alternative--  they must
 have lived and died where they are4    
,important objections1 however1 at once 
suggest themselves to this view4  ,how  
can animal life be conceived to exist   
under such conditions of light1         
temperature1 pressure1 and aeration as  
must obtain at these vast depths8    ,to
 this one can only reply that we know   
for a certainty that even very          

highly-organized animals do continue to 
live at a depth of #cjj and #djj        
fathoms1 inasmuch as they have been     
dredged up thence2 and that the         
difference in the amount of light and   
heat at #djj and at #b1jjj fathoms is   
probably1 so to speak1 very far less    
than the difference in complexity of    
organisation between these animals and  
the humbler ,protozoa and  ,protophyta  
of the deep-sea soundings4    ,i        
confess1 though as yet far from         
regarding it proved that the            
,globigerinoe live at these depths1 the 
balance of probabilities seems  to me to
 incline in that direction4 ,and there  
is one circumstance which  weighs       
strongly in my mind4 ,it may be taken as
 a law that any genus of  animals which 
is found far back in time is capable of 
living under a  great variety of        
circumstances as regards light1         
temperature1 and  pressure4 ,now1 the   
genus ,globigerina is abundantly        
represented in the  cretaceous epoch1   

and perhaps earlier4    ,i abstain1     
however1 at present from drawing any    
positive conclusions1  preferring rather
 to await the result of more extended   
observations4#f    ,footnote #f3        
,appendix to ,report on ,deep-sea       
,soundings in the ,atlantic  ,ocean1 by 
,lieut4-,commander ,joseph ,dayman4     
#aheg4    ,dr4 ,wallich1 ,professor     
,wyville ,thomson1 and ,dr4 ,carpenter  
concluded that  the ,globigerinoe live  
at the bottom4 ,dr4 ,wallich writes in  
#ahfb--;,by  sinking very fine gauze    
nets to considerable depths1 ,i have    
repeatedly  satisfied myself that       
,globigerina does not occur in the      
superficial  strata of the ocean4#g     
,moreover1 having obtained certain      
living star-  fish from a depth of      
#a1bfj fathoms1 and found their stomachs
 full of  fresh-looking ,globigerinoe   
and their dbris--he adduces this fact   
in support of his belief that the       
,globigerinoe live at the bottom4       
,footnote #g3 ,the ,north ,atlantic     

,sea-bed1 p4 #acg4    ,on the other     
hand1 ,mller1 ,haeckel1 ,major ,owen1   
,mr4 ,gwyn ,jeffries1 and  other        
observers1 found that ,globigerinoe1    
with the allied genera  ,orbulina and   
,pulvinulina1 sometimes occur abundantly
 at the surface  of the sea1 the shells 
of these pelagic forms being not        
unfrequently  provided with the long    
spines noticed by ,macdonald2 and in    
#ahfe and #ahff1  ,major ,owen more     
especially insisted on the importance of
 this fact4 ,the  recent work of the    
,challenger fully confirms ,major       
,owen's statement4 ,in  the paper       
recently published in the proceedings of
 the ,royal ,society1#h  from which a   
quotation has already been made1        
,professor ,wyville ,thomson  says3--   
,i had formed and expressed a very      
strong opinion on the matter4 ,it       
seemed to me that the evidence was      
conclusive that the ,foraminifera  which
 formed the ,globigerina ooze lived on  
the bottom1 and that the  occurrence of 

individuals on the surface was          
accidental and exceptional2  but after  
going into the thing carefully1 and     
considering the mass of  evidence which 
has been accumulated by ,mr4 ,murray1 ,i
 now admit that ,i was  in error2 and ,i
 agree with him that it may be taken as 
proved that all  the materials of such  
deposits1 with the exception1 of course1
 of the  remains of animals which we now
 know to live at the bottom at all      
depths1  which occur in the deposit as  
foreign bodies1 are derived from the    
surface4    ,footnote #h3 ,preliminary  
,notes on the ,nature of the ,sea-bottom
 procured  by the soundings of ,h4,m4,s4
 ,challenger during her cruise in the   
,southern  ,seas1 in the early part of  
the year #ahgd4--,proceedings of the    
,royal  ,society1 ,nov4 #bf1 #ahgd4     
,mr4 ,murray has combined with a careful
 examination of the soundings a         
constant use of the tow-net1 usually at 
the surface1 but also at depths  of from
 ten to one hundred fathoms2 and he     

finds the closest relation to  exist    
between the surface fauna of any        
particular locality and the  deposit    
which is taking place at the bottom4 ,in
 all seas1 from the  equator to the     
polar ice1 the tow-net contains         
,globigerinoe4 ,they are  more abundant 
and of a larger size in warmer seas2    
several varieties1  attaining a large   
size and presenting marked varietal     
characters1 are  found in the           
intertropical area of the ,atlantic4 ,in
 the latitude of  ,kerguelen they are   
less numerous and smaller1 while further
 south they  are still more dwarfed1 and
 only one variety1 the typical          
,globigerina  bulloides1 is represented4
 ,the living ,globigerinoe from the     
tow-net  are singularly different in    
appearance from the dead shells we find 
at  the bottom4 ,the shell is clear and 
transparent1 and each of the pores      
which penetrate it is surrounded by a   
raised crest1 the crest round  adjacent 
pores coalescing into a roughly         

hexagonal network1 so that the  pores   
appear to lie at the bottom of a        
hexagonal pit4 ,at each angle of  this  
hexagon the crest gives off a delicate  
flexible calcareous spine1  which is    
sometimes four or five times the        
diameter of the shell in  length4 ,the  
spines radiate symmetrically from the   
direction of the centre  of each chamber
 of the shell1 and the sheaves of long  
transparent needles  crossing one       
another in different directions have a  
very beautiful  effect4 ,the smaller    
inner chambers of the shell are entirely
 filled with  an orange-yellow granular 
sarcode2 and the large terminal chamber 
usually  contains only a small irregular
 mass1 or two or three small masses run 
together1 of the same yellow sarcode    
stuck against one side1 the  remainder  
of the chamber being empty4 ,no definite
 arrangement and no  approach to        
structure was observed in the sarcode1  
and no  differentiation1 with the       
exception of round bright-yellow        

oil-globules1  very much like those     
found in some of the radiolarians1 which
 are  scattered1 apparently irregularly1
 in the sarcode4 ,we never have been    
able to detect1 in any of the large     
number of ,globigerinoe which we  have  
examined1 the least trace of            
pseudopodia1 or any extension1 in any   
form1 of the sarcode beyond the shell4  
99       99       99       99       99  
,in specimens taken with the tow-net the
 spines are very usually absent2  but   
that is probably on account of their    
extreme tenuity2 they are broken  off by
 the slightest touch4 ,in fresh examples
 from the surface1 the dots  indicating 
the origin of the lost spines may almost
 always be made out  with a high power4 
,there are never spines on the          
,globigerinoe from the  bottom1 even in 
the shallowest water4      ,there can   
now be no doubt1 therefore1 that        
,globigerinoe live at the top  of the   
sea2 but the question may still be      
raised whether they do not also  live at

 the bottom4 ,in favour of this view1 it
 has been urged that the  shells of the 
,globigerinoe of the surface never      
possess such thick  walls as those which
 are fouled at the bottom1 but ,i       
confess that ,i doubt  the accuracy of  
this statement4 ,again1 the occurrence  
of minute  ,globigerinoe in all stages  
of development1 at the greatest depths1 
is  brought forward as evidence that    
they live in situ4 ,but considering the 
extent to which the surface organisms   
are devoured1 without  discrimination of
 young and old1 by ,salpoe and the like1
 it is not  wonderful that shells of all
 ages should be among the rejectamenta4 
,nor  can the presence of the soft parts
 of the body in the shells which form   
the ,globigerina ooze1 and the fact1 if 
it be one1 that animals living  at the  
bottom use them as food1 be considered  
as conclusive evidence that  the        
,globigerinoe live at the bottom4 ,such 
as die at the surface1 and  even many of
 those which are swallowed by other     

animals1 may retain much  of their      
protoplasmic matter when they reach the 
depths at which the  temperature sinks  
to #cd or #cb ,fahrenheit1 where        
decomposition must  become exceedingly  
slow4    ,another consideration appears 
to me to be in favour of the view that  
the  ,globigerinoe and their allies are 
essentially surface animals4 ,this is   
the fact brought out by the             
,challenger's work1 that they have a    
southern limit of distribution1 which   
can hardly depend upon anything but  the
 temperature of the surface water4 ,and 
it is to be remarked that this  southern
 limit occurs at a lower latitude in the
 ,antarctic seas than it  does in the   
,north ,atlantic4 ,according to ,dr4    
,wallich 7,the ,north ,atlantic  ,sea   
,bed1 p4 #aeg7 ,globigerina is the      
prevailing form in the deposits  between
 the ,faroe ,islands and ,iceland1 and  
between ,iceland and ,east              
,greenland--or1 in other words1 in a    
region of the sea-bottom which lies     

altogether north of the parallel of #fj 
,n42 while in the southern seas1  the   
,globigerinoe become dwarfed and almost 
disappear between #ej and  #ee ,s4 ,on  
the other hand1 in the sea of           
,kamschatka1 the ,globigerinoe  have    
vanished in #ef ,n41 so that the        
persistence of the ,globigerina  ooze in
 high latitudes1 in the ,north          
,atlantic1 would seem to depend on  the 
northward curve of the isothermals      
peculiar to this region2 and it is      
difficult to understand how the         
formation of ,globigerina ooze can be   
affected by this climatal peculiarity   
unless it be effected by surface        
animals4    ,whatever may be the mode of
 life of the ,foraminifera1 to which the
  calcareous element of the deep-sea    
chalk owes its existence1 the fact  that
 it is the chief and most widely spread 
material of the sea-bottom in  the      
intermediate zone1 throughout both the  
,atlantic and ,pacific ,oceans1  and the
 ,indian ,ocean1 at depths from a few   

hundred to over two thousand  fathoms1  
is established4 ,but it is not the only 
extensive deposit which  is now taking  
place4 ,in #ahec1 ,count ,pourtals1 an  
officer of the ,united  ,states ,coast  
,survey1 which has done so much for     
scientific hydrography1  observed1 that 
the mud forming the sea-bottom at depths
 of one hundred  and fifty fathoms1 in  
#ca #cb' ,n41 #gi #ce' ,w41 off the     
,coast of ,florida1  was a mixture1 in  
about equal proportions1 of             
,globigerinoe and black  sand1 probably 
greensand1 as it makes a green mark when
 crushed on  paper4 ,professor ,bailey1 
examining these grains microscopically1 
found  that they were casts of the      
interior cavities of ,foraminifera1     
consisting of a mineral known as        
,glauconite1 which is a silicate of     
iron and alumina4 ,in these casts the   
minutest cavities and finest tubes  in  
the ,foraminifer were sornetilnes       
reproduced in solid counterparts of  the
 glassy mineral1 while the calcareous   

original had been entirely  dissolved   
away4    ,contemporaneously with these  
observations1 the indefatigable         
,ehrenberg  had discovered that the     
greensands of the geologist were largely
 made  up of casts of a similar         
character1 and proved the existence of  
,foraminifera at a very ancient         
geological epoch1 by discovering such   
casts in a greensand of ,lower ,silurian
 age1 which occurs near ,st4            
,petersburg4    ,subsequently1 ,messrs4 
,parker and ,jones discovered similar   
casts in  process of formation1 the     
original shell not having disappeared1  
in  specimens of the sea-bottom of the  
,australian seas1 brought home by the   
late ,professor ,jukes4 ,and the        
,challenger has observed a deposit of a 
similar character in the course of the  
,agulhas current1 near the ,cape of     
,good ,hope1 and in some other          
localities not yet defined4    ,it would
 appear that this infiltration of       
,foraminifera shells with  ,glauconite  

does not take place at great depths1 but
 rather in what may  be termed a        
sublittoral region1 ranging from a      
hundred to three hundred  fathoms4 ,it  
cannot be ascribed to any local cause1  
for it takes place1  not only over large
 areas in the ,gulf of ,mexico and the  
,coast of ,florida1  but in the ,south  
,atlantic and in the ,pacific4 ,but what
 are the conditions  which determine its
 occurrence1 and whence the silex1 the  
iron1 and the  alumina 7with perhaps    
potash and some other ingredients in    
small  quantity7 of which the           
,glauconite is composed1 proceed1 is a  
point on  which no light has yet been   
thrown4 ,for the present we must be     
content  with the fact that1 in certain 
areas of the intermediate zone1         
greensand is replacing and representing 
the primitively calcareo-  silicious    
ooze4    ,the investigation of the      
deposits which are now being formed in  
the basin  of the ,mediterranean1 by the
 late ,professor ,edward ,forbes1 by    

,professor  ,williamson and more        
recently by ,dr4 ,carpenter1 and a      
comparison of the  results thus obtained
 with what is known of the surface      
fauna1 have  brought to light the       
remarkable fact1 that while the surface 
and the  shallows abound with           
,foraminifera and other calcareous      
shelled  organisms1 the indications of  
life become scanty at depths beyond #ejj
 or  #fjj fathoms1 while almost all     
traces of it disappear at greater       
depths1  and at #a1jjj to #b1jjj fathoms
 the bottom is covered with a fine clay4
    ,dr4 ,carpenter has discussed the   
significance of this remarkable fact1   
and  he is disposed to attribute the    
absence of life at great depths1 partly 
to the absence of any circulation of the
 water of the ,mediterranean at  such   
depths1 and partly to the exhaustion of 
the oxygen of the water by  the organic 
matter contained in the fine clay1 which
 he conceives to be  formed by the      
finest particles of the mud brought down

 by the rivers  which flow into the     
,mediterranean4    ,however this may be1
 the explanation thus offered of the    
presence of the  fine mud1 and of the   
absence of organisms which ordinarily   
live at the  bottom1 does not account   
for the absence of the skeletons of the 
organisms which undoubtedly abound at   
the surface of the ,mediterranean2  and 
it would seem to have no application to 
the remarkable fact  discovered by the  
,challenger1 that in the open ,atlantic 
and ,pacific  ,oceans1 in the midst of  
the great intermediate zone1 and        
thousands of  miles away from the       
embouchure of any river1 the sea-bottom1
 at depths  approaching to and beyond   
#c1jjj fathoms1 no longer consists of   
,globigerina ooze1 but of an excessively
 fine red clay4    ,professor ,thomson  
gives the following account of this     
capital  discovery3--    ,according to  
our present experience1 the deposit of  
,globigerina ooze  is limited to water  
of a certain depth1 the extreme limit of

 the pure  characteristic formation     
being placed at a depth of somewhere    
about #b1bej  fathoms4 ,crossing from   
these shallower regions occupied by the 
ooze into  deeper soundings1 we find1   
universally1 that the calcareous        
formation  gradually passes into1 and is
 finally replaced by1 an extremely fine 
pure  clay1 which occupies1 speaking    
generally1 all depths below #b1ejj      
fathoms1  and consists almost entirely  
of a silicate of the red oxide of iron  
and  alumina4 ,the transition is very   
slow1 and extends over several hundred  
fathoms of increasing depth2 the shells 
gradually lose their sharpness of       
outline1 and assume a kind of 'rotten'  
look and a brownish colour1 and  become 
more and more mixed with a fine         
amorphous red-brown powder1 which       
increases steadily in proportion until  
the lime has almost entirely            
disappeared4 ,this brown matter is in   
the finest possible state of            
subdivision1 so fine that when1 after   

sifting it to separate any  organisms it
 might contain1 we put it into jars to  
settle1 it remained  for days in        
suspension1 giving the water very much  
the appearance and  colour of chocolate4
    ,in indicating the nature of the    
bottom on the charts1 we came1 from     
experience and without any theoretical  
considerations1 to use three terms  for 
soundings in deep water4 ,two of these1 
,gl4 oz4 and r4 cl41 were very          
definite1 and indicated strongly-marked 
formations1 with apparently but  few    
characters in common2 but we frequently 
got soundings which we could  not       
exactly call ',globigerina ooze' or 'red
 clay1' and before we were  fully aware 
of the nature of these1 we were in the  
habit of indicating  them as 'grey ooze'
 7gr4 oz47 ,we now recognise the 'grey  
ooze' as an  intermediate stage between 
the ,globigerina ooze and the red clay2 
we  find that on one side1 as it were1  
of an ideal line1 the red clay  contains
 more and more of the material of the   

calcareous ooze1 while on  the other1   
the ooze is mixed with an increasing    
proportion of 'red clay4'    ,although  
we have met with the same phenomenon so 
frequently1 that we  were at length able
 to predict the nature of the bottom    
from the depth of  the soundings with   
absolute certainty for the ,atlantic and
 the ,southern  ,sea1 we had1 perhaps1  
the best opportunity of observing it in 
our first  section across the ,atlantic1
 between ,teneriffe and ,st4 ,thomas4   
,the first  four stations on this       
section1 at depths from #a1ebe to #b1bbj
 fathoms1  show ,globigerina ooze4 ,from
 the last of these1 which is about #cjj 
miles  from ,teneriffe1 the depth       
gradually increases to #b1gdj fathoms at
 #ejj1  and #b1iej fathoms at #gej miles
 from ,teneriffe4 ,the bottom in these  
two  soundings might have been called   
'grey ooze1' for although its nature has
  altered entirely from the ,globigerina
 ooze1 the red clay into which it  is   
rapidly passing still contains a        

considerable admixture of carbonate  of 
lime4    ,the depth goes on increasing  
to a distance of #a1aej miles from      
,teneriffe1 when it reaches #c1aej      
fathoms2 there the clay is pure and     
smooth1 and contains scarcely a trace of
 lime4 ,from this great depth the       
bottom gradually rises1 and1 with       
decreasing depth1 the grey colour and   
the calcareous composition of the ooze  
return4 ,three soundings in #b1jej1     
#a1ijj1 and #a1iej fathoms on the       
',dolphin ,rise' gave highly            
characteristic  examples of the         
,globigerina formation4 ,passing from   
the middle plateau  of the ,atlantic    
into the western trough1 with depths a  
little over #c1jjj  fathoms1 the red    
clay returned in all its purity2 and our
 last sounding1  in #a1dbj fathoms1     
before reaching ,sombrero1 restored the 
,globigerina  ooze with its peculiar    
associated fauna4    ,this section shows
 also the wide extension and the vast   
geological  importance of the red clay  

formation4 ,the total distance from     
,teneriffe  to ,sombrero is about #b1gjj
 miles4 ,proceeding from east to west1  
we have--    ,about     #hj miles of    
volcanic mud and sand1          #cej    
,globigerina ooze1        #a1jej        
red clay1          #ccj                 
,globigerina ooze1          #hej        
red clay1           #dj                 
,globigerina ooze2    giving a total of 
#a1ijj miles of red clay to #gbj miles  
of ,globigerina  ooze4    ,the nature   
and origin of this vast deposit of clay 
is a question of the  very greatest     
interest2 and although ,i think there   
can be no doubt that  it is in the main 
solved1 yet some matters of detail are  
still involved  in difficulty4 ,my first
 impression was that it might be the    
most minutely  divided material1 the    
ultimate sediment produced by the       
disintegration of  the land1 by rivers  
and by the action of the sea on exposed 
coasts1 and  held in suspension and     
distributed by ocean currents1 and only 

making  itself manifest in places       
unoccupied by the ,globigerina ooze4    
,several  circumstances seemed1 however1
 to negative this mode of origin4 ,the  
formation seemed too uniform3 wherever  
we met with it1 it had the same         
character1 and it only varied in        
composition in containing less or more  
carbonate of lime4    ,again1 the were  
gradually becoming more and more        
convinced that all the  important       
elements of the ,globigerina ooze lived 
on the surface1 and it  seemed evident  
that1 so long as the condition on the   
surface remained the  same1 no          
alteration of contour at the bottom     
could possibly prevent its              
accumulation2 and the surface conditions
 in the ,mid-,atlantic were very        
uniform1 a moderate current of a very   
equal temperature passing  continuously 
over elevations and depressions1 and    
everywhere yielding to  the tow-net the 
ooze-forming ,foraminifera in the same  
proportion4 ,the  ,mid-,atlantic swarms 

with pelagic ,mollusca1 and1 in moderate
 depths1 the  shells of these are       
constantly mixed with the ,globigerina  
ooze1  sometimes in number sufficient to
 make up a considerable portion of its  
bulk4 ,it is clear that these shells    
must fall in equal numbers upon the  red
 clay1 but scarcely a trace of one of   
them is ever brought up by the  dredge  
on the red clay area4 ,it might be      
possible to explain the absence  of     
shell-secreting animals living on the   
bottom1 on the supposition that  the    
nature of the deposit was injurious to  
them2 but then the idea of a  current   
sufficiently strong to sweep them away  
is negatived by the  extreme fineness of
 the sediment which is being laid down2 
the absence of  surface shells appears  
to be intelligible only on the          
supposition that  they are in some way  
removed4    ,we conclude1 therefore1    
that the 'red clay' is not an additional
  substance introduced from without1 and
 occupying certain depressed  regions on

 account of some law regulating its     
deposition1 but that it is  produced by 
the removal1 by some means or other1    
over these areas1 of the  carbonate of  
lime1 which forms probably about #ih per
 cent4 of the  material of the          
,globigerina ooze4 ,we can trace1       
indeed1 every  successive stage in the  
removal of the carbonate of lime in     
descending  the slope of the ridge or   
plateau where the ,globigerina ooze is  
forming1 to the region of the clay4 ,we 
find1 first1 that the shells of         
pteropods and other surface ,mollusca   
which are constantly falling on  the    
bottom1 are absent1 or1 if a few remain1
 they are brittle and yellow1  and      
evidently decaying rapidly4 ,these      
shells of ,mollusca decompose more      
easily and disappear sooner than the    
smaller1 and apparently more  delicate1 
shells of rhizopods4 ,the smaller       
,foraminifera now give way1  and are    
found in lessening proportion to the    
larger2 the coccoliths first  lose their

 thin outer border and then disappear2  
and the clubs of the  rhabdoliths get   
worn out of shape1 and are last seen1   
under a high power1  as infinitely      
minute cylinders scattered over the     
field4 ,the larger  ,foraminifera are   
attacked1 and instead of being vividly  
white and  delicately sculptured1 they  
become brown and worn1 and finally they 
break  up1 each according to its        
fashion2 the chamber-walls of           
,globigerina  fall into wedge-shaped    
pieces1 which quickly disappear1 and a  
thick rough  crust breaks away from the 
surface of ,orbulina1 leaving a thin    
inner  sphere1 at first beautifully     
transparent1 but soon becoming opaque   
and  crumbling away4    ,in the meantime
 the proportion of the amorphous 'red   
clay' to the  calcareous elements of all
 kinds increases1 until the latter      
disappear1  with the exception of a few 
scattered shells of the larger          
,foraminifera1 which are still found    
even in the most characteristic  samples

 of the 'red clay4'    ,there seems to  
be no room left for doubt that the red  
clay is  essentially the insoluble      
residue1 the ash1 as it were1 of the    
calcareous organisms which form the     
,globigerina ooze1 after the  calcareous
 matter has been by some means removed4 
,an ordinary mixture of  calcareous     
,foraminifera with the shells of        
pteropods1 forming a fair  sample of    
,globigerina ooze from near ,st4        
,thomas1 was carefully washed1  and     
subjected by ,mr4 ,buchanan to the      
action of weak acid2 and he found  that 
there remained after the carbonate of   
lime had been removed1 about #a  per    
cent4 of a reddish mud1 consisting of   
silica1 alumina1 and the red  oxide of  
iron4 ,this experiment has been         
frequently repeated with  different     
samples of ,globigerina ooze1 and always
 with the result that  a small          
proportion of a red sediment remains1   
which possesses all the  characters of  
the red clay4           99       99     

99       99       99    ,it seems       
evident from the observations here      
recorded1 that clay1 which  we have     
hitherto looked upon as essentially the 
product of the  disintegration of older 
rocks1 may be1 under certain            
circumstances1 an  organic formation    
like chalk2 that1 as a matter of fact1  
an area on the  surface of the globe1   
which we have shown to be of vast       
extent1 although  we are still far from 
having ascertained its limits1 is being 
covered by  such a deposit at the       
present day4    ,it is impossible to    
avoid associating such a formation with 
the fine1  smooth1 homogeneous clays and
 schists1 poor in fossils1 but showing  
worm-  tubes and tracks1 and bunches of 
doubtful branching things1 such as      
,oldhamia1 silicious sponges1 and       
thin-shelled peculiar shrimps4 ,such    
formations1 more or less metamorphosed1 
are very familiar1 especially to  the   
student of palaeozoic geology1 and they 
often attain a vast thickness4  ,one is 

inclined1 from the great resemblance    
between them in composition  and in the 
general character of the included fauna1
 to suspect that these  may be organic  
formations1 like the modern red clay of 
the ,atlantic and  ,southern ,sea1      
accumulations of the insoluble ashes of 
shelled creatures4    ,the dredging in  
the red clay on the #acth of ,march was 
usually rich4 ,the  bag contained       
examples1 those with calcareous shells  
rather stunted1 of  most of the         
characteristic deep-water groups of the 
,southern ,sea1  including              
,umbellularia1 ,euplectella1            
,pterocrinus1 ,brisinga1 ,ophioglypha1  
,pourtalesia1 and one or two ,mollusca4 
,this is1 however1 very rarely  the     
case4 ,generally the red clay is barren1
 or contains only a very small  number  
of forms4    ,it must be admitted that  
it is very difficult1 at present1 to    
frame any  satisfactory explanation of  
the mode of origin of this singular     
deposit  of red clay4    ,i cannot say  

that the theory put forward tentatively1
 and with much  reservation by          
,professor ,thomson1 that the calcareous
 matter is dissolved  out by the        
relatively fresh water of the deep      
currents from the ,antarctic  regions1  
appears satisfactory to me4 ,nor do ,i  
see my way to the  acceptance of the    
suggestion of ,dr4 ,carpenter1 that the 
red clay is the  result of the          
decomposition of previously-formed      
greensand4 ,at present  there is no     
evidence that greensand casts are ever  
formed at great  depths2 nor has it been
 proved that ,glauconite is decomposable
 by the  agency of water and carbonic   
acid4    ,i think it probable that we   
shall have to wait some time for a      
sufficient  explanation of the origin of
 the abyssal red clay1 no less than for 
that  of the sublittoral greensand in   
the intermediate zone4 ,but the         
importance  of the establishment of the 
fact that these various deposits are    
being  formed in the ocean1 at the      

present day1 remains the same2 whether  
its  rationale be understood or not4    
,for1 suppose the globe to be evenly    
covered with sea1 to a depth say of a   
thousand fathoms--then1 whatever might  
be the mineral matter composing  the    
sea-bottom1 little or no deposit would  
be formed upon it1 the  abrading and    
denuding action of water1 at such a     
depth1 being exceedingly  slight4       
,next1 imagine sponges1 ,radiolaria1    
,foraminifera1 and diatomaceous  plants1
 such as those which now exist in the   
deep-sea1 to be introduced3  they would 
be distributed according to the same    
laws as at present1 the  sponges 7and   
possibly some of the ,foraminifera71    
covering the bottom1  while other       
,foraminifera1 with the ,radiolaria and 
,diatomacea1 would  increase and        
multiply in the surface waters4 ,in     
accordance with the  existing state of  
things1 the ,radiolaria and ,diatoms    
would have a  universal distribution1   
the latter gathering most thickly in the

 polar  regions1 while the ,foraminifera
 would be largely1 if not exclusively1  
confined to the intermediate zone2 and1 
as a consequence of this  distribution1 
a bed of chalk would begin to form in   
the intermediate  zone1 while caps of   
silicious rock would accumulate on the  
circumpolar  regions4    ,suppose1      
further1 that a part of the intermediate
 area were raised to  within two or     
three hundred fathoms of the            
surface--for anything that we  know to  
the contrary1 the change of level might 
determine the  substitution of greensand
 for the chalk2 while1 on the other     
hand1 if  part of the same area were    
depressed to three thousand fathoms1    
that  change might determine the        
substitution of a different silicate of 
alumina and iron--namely1 clay--for the 
chalk that would otherwise be  formed4  
,if the ,challenger hypothesis1 that the
 red clay is the residue left by        
dissolved ,foraminiferous skeletons1 is 
correct1 then all these deposits  alike 

would be directly1 or indirectly1 the   
product of living organisms4  ,but just 
as a silicious deposit may be           
metamorphosed into opal or  quartzite1  
and chalk into marble1 so known         
metamorphic agencies may  metamorphose  
clay into schist1 clay-slate1 slate1    
gneiss1 or even  granite4 ,and thus1 by 
the agency of the lowest and simplest of
 organisms1  our imaginary globe might  
be covered with strata1 of all the chief
 kinds  of rock of which the known crust
 of the earth is composed1 of indefinite
  thickness and extent4    ,the bearing 
of the conclusions which are now either 
established1 or  highly probable1       
respecting the origin of silicious1     
calcareous1 and  clayey rocks1 and their
 metamorphic derivatives1 upon the      
archaeology of  the earth1 the          
elucidation of which is the ultimate    
object of the  geologist1 is of no small
 importance4    ,a hundred years ago the
 singular insight of ,linnaeus enabled  
him to say  that fossils are not the    

children but the parents of rocks1#i and
 the  whole effect of the discoveries   
made since his time has been to compile 
a  larger and larger commentary upon    
this text4 ,it is1 at present1 a        
perfectly tenable hypothesis that all   
siliceous and calcareous rocks are      
either directly1 or indirectly1 derived 
from material which has1 at one  time or
 other1 formed part of the organized    
framework of living  organisms4 ,whether
 the same generalization may be extended
 to aluminous  rocks1 depends upon the  
conclusion to be drawn from the facts   
respecting  the red clay areas brought  
to light by the ,challenger4 ,if we     
accept the  view taken by ,wyville      
,thomson and his colleagues--that the   
red clay is  the residuum left after the
 calcareous matter of the ,globigerinoe 
ooze  has been dissolved away--then clay
 is as much a product of life as        
limestone1 and all known derivatives of 
clay may have formed part of  animal    
bodies4    ,footnote #i3 ,petrificata   

montium calcariorum non filii sed       
parentes  sunt1 cum omnis calx oriatur  
ab animalibus4--,systema ,naturae1 ,ed4 
xii41  t4 iii41 p4 #aed4 ,it must be    
recollected that ,linnaeus included     
silex1 as  well as limestone1 under the 
name of calx1 and that he would probably
  have arranged ,diatoms among animals1 
as part of chaos4 ,ehrenberg quotes     
another even more pithy passage1 which  
,i have not been able to find in  any   
edition of the ,systema accessible to   
me3 ,sic lapides ab  animalibus1 nec    
vice versa4 ,sic runes saxei non        
primaevi1 sed temporis  filiae4    ,so  
long as the ,globigerinoe21 actually    
collected at the surface1 have  not been
 demonstrated to contain the elements of
 clay1 the ,challenger  hypothesis1 as  
,i may term it1 must be accepted with   
reserve and  provisionally1 but1 at     
present1 ,i cannot but think that it is 
more  probable than any other suggestion
 which has been made4    ,accepting it  
provisionally1 we arrive at the         

remarkable result that all  the chief   
known constituents of the crust of the  
earth may have formed  part of living   
bodies2 that they may be the ash of     
protoplasm2 that the  rupes saxei are   
not only temporis1 but vitae filiae2    
and1  consequently1 that the time during
 which life has been active on the      
globe may be indefinitely greater than  
the period1 the commencement of  which  
is marked by the oldest known rocks1    
whether fossiliferous or                
unfossiliferous4    ,and thus we are led
 to see where the solution of a great   
problem and  apparent paradox of geology
 may lie4 ,satisfactory evidence now    
exists  that some animals in the        
existing world have been derived by a   
process of  gradual modification from   
pre-existing forms4 ,it is undeniable1  
for  example1 that the evidence in      
favour of the derivation of the horse   
from  the later tertiary ,hipparion1 and
 that of the ,hipparion from            
,anchitherium1 is as complete and cogent

 as such evidence can reasonably  be    
expected to be2 and the further         
investigations into the history of the  
tertiary mammalia are pushed1 the       
greater is the accumulation of evidence 
having the same tendency4 ,so far from  
palaeontology lending no support to  the
 doctrine of evolution--as one sees     
constantly asserted--that  doctrine1 if 
it had no other support1 would have been
 irresistibly forced  upon us by the    
palaeontological discoveries of the last
 twenty years4    ,if1 however1 the     
diverse forms of life which now exist   
have been produced  by the modification 
of previously-existing less divergent   
forms1 the  recent and extinct species1 
taken as a whole1 must fall into series 
which  must converge as we go back in   
time4 ,hence1 if the period represented 
by  the rocks is greater than1 or       
co-extensive with1 that during which    
life  has existed1 we ought1 somewhere  
among the ancient formations1 to arrive 
at the point to which all these series  

converge1 or from which1 in other       
words1 they have diverged--the primitive
 undifferentiated protoplasmic  living  
things1 whence the two great series of  
plants and animals have  taken their    
departure4    ,but1 as a matter of fact1
 the amount of convergence of series1 in
  relation to the time occupied by the  
deposition of geological formations1  is
 extraordinarily small4 ,of all animals 
the higher ,vertebrata are the  most    
complex2 and among these the carnivores 
and hoofed animals  7,ungulata7 are     
highly differentiated4 ,nevertheless1   
although the  different lines of        
modification of the ,carnivora and those
 of the  ,ungulata1 respectively1       
approach one another1 and1 although each
 group  is represented by less          
differentiated forms in the older       
tertiary rocks  than at the present day1
 the oldest tertiary rocks do not bring 
us near  the primitive form of either4  
,if1 in the same way1 the convergence of
 the  varied forms of reptiles is       

measured against the time during which  
their  remains are preserved--which is  
represented by the whole of the tertiary
  and mesozoic formations--the amount of
 that convergence is far smaller  than  
that of the lines of mammals between the
 present time and the  beginning of the 
tertiary epoch4 ,and it is a broad fact 
that1 the lower  we go in the scale of  
organization1 the fewer signs are there 
of  convergence towards the primitive   
form from whence all must have          
diverged1 if evolution be a fact4       
,nevertheless1 that it is a fact in some
  cases1 is proved1 and ,i1 for one1    
have not the courage to suppose that    
the mode in which some species have     
taken their origin is different from    
that in which the rest have originated4 
,what1 then1 has become of all the      
marine animals which1 on the hypothesis 
of evolution1 must have existed in      
myriads in those seas1 wherein the  many
 thousand feet of ,cambrian and         
,laurentian rocks now devoid1 or almost 

devoid1 of any trace of life were       
deposited8    ,sir ,charles ,lyell long 
ago suggested that the azoic character  
of these  ancient formations might be   
due to the fact that they had undergone 
extensive metamorphosis2 and readers of 
the ,principles of ,geology will  be    
familiar with the ingenious manner in   
which he contrasts the theory of  the   
,gnome1 who is acquainted only with the 
interior of the earth1 with  those of   
ordinary philosophers1 who know only its
 exterior4    ,the metamorphism         
contemplated by the great modern        
champion of rational  geology is1       
mainly1 that brought about by the       
exposure of rocks to  subterranean heat2
 and where no such heat could be shown  
to have  operated1 his opponents assumed
 that no metamorphosis could have taken 
place4 ,but the formation of greensand1 
and still more that of the red  clay 7if
 the ,challenger hypothesis be correct7 
affords an insight into  a new kind of  
metamorphosis--not igneous1 but         

aqueous--by which the  primitive nature 
of a deposit may be masked as completely
 as it can be by  the agency of heat4   
,and1 as ,wyville ,thomson suggests1 in 
the passage ,i  have quoted above 7p4   
#ag71 it further enables us to assign a 
new cause  for the occurrence1 so       
puzzling hitherto1 of thousands of feet 
of  unfossiliferous fine-grained schists
 and slates1 in the midst of  formations
 deposited in seas which certainly      
abounded in life4 ,if the  great deposit
 of red clay now forming in the eastern 
valley of the  ,atlantic were           
metamorphosed into slate and then       
upheaved1 it would  constitute an azoic 
rock of enormous extent4 ,and yet that  
rock is now  forming in the midst of a  
sea which swarms with living beings1 the
 great  majority of which are provided  
with calcareous or silicious shells and 
skeletons2 and1 therefore1 are such as1 
up to this time1 we should have  termed 
eminently preservable4    ,thus the     
discoveries made by the ,challenger     

expedition1 like all recent  advances in
 our knowledge of the phenomena of      
biology1 or of the changes  now being   
effected in the structure of the surface
 of the earth1 are in  accordance with  
and lend strong support to1 that        
doctrine of  ,uniformitarianism1 which1 
fifty years ago1 was held only by a     
small  minority of ,english             
geologists--,lyell1 ,scrope1 and ,de la 
,beche--but now1  thanks to the         
long-continued labours of the first two1
 and mainly to  those of ,sir ,charles  
,lyell1 has gradually passed from the   
position of a  heresy to that of        
catholic doctrine4    ,applied within   
the limits of the time registered by the
 known fraction of  the crust of the    
earth1 ,i believe that uniformitarianism
 is unassailable4  ,the evidence that1  
in the enormous lapse of time between   
the deposition  of the lowest           
,laurentian strata and the present day1 
the forces which  have modified the     
surface of the crust of the earth were  

different in  kind1 or greater in the   
intensity of their action1 than those   
which are  now occupied in the same     
work1 has yet to be produced4 ,such     
evidence as  we possess all tends in the
 contrary direction1 and is in favour of
 the  same slow and gradual changes     
occurring then as now4    ,but this     
conclusion in nowise conflicts with the 
deductions of the  physicist from his no
 less clear and certain data4 ,it may be
 certain that  this globe has cooled    
down from a condition in which life     
could not have  existed2 it may be      
certain that1 in so cooling1 its        
contracting crust  must have undergone  
sudden convulsions1 which were to our   
earthquakes as  an earthquake is to the 
vibration caused by the periodical      
eruption of a  ,geyser2 but in that     
case1 the earth must1 like other        
respectable parents1  have sowed her    
wild oats1 and got through her turbulent
 youth1 before we1  her children1 have  
any knowledge of her4    ,so far as the 

evidence afforded by the superficial    
crust of the earth  goes1 the modern    
geologist can1 ex animo1 repeat the     
saying of ,hutton1  ,we find no vestige 
of a beginning--no prospect of an end4  
,however1 he  will add1 with ,hutton1   
,but in thus tracing back the natural   
operations  which have succeeded each   
other1 and mark to us the course of time
 past1  we come to a period in which we 
cannot see any further4 ,and if he seek 
to peer into the darkness of this       
period1 he will welcome the light       
proffered by physics and mathematics4   
,,iv      ,,yeast    #ahga    ,it has   
been known1 from time immemorial1 that  
the sweet liquids which may  be obtained
 by expressing the juices of the fruits 
and stems of various  plants1 or by     
steeping malted barley in hot water1 or 
by mixing honey  with water--are liable 
to undergo a series of very singular    
changes1 if  freely exposed to the air  
and left to themselves1 in warm weather4
  ,however clear and pellucid the liquid

 may have been when first prepared1     
however carefully it may have been      
freed1 by straining and filtration1     
from even the finest visible impurities1
 it will not remain clear4 ,after  a    
time it will become cloudy and turbid2  
little bubbles will be seen  rising to  
the surface1 and their abundance will   
increase until the liquid  hisses as if 
it were simmering on the fire4 ,by      
degrees1 some of the solid  particles   
which produce the turbidity of the      
liquid collect at its  surface into a   
scum1 which is blown up by the emerging 
air-bubbles into a  thick1 foamy froth4 
,another moiety sinks to the bottom1 and
 accumulates  as a muddy sediment1 or   
lees4    ,when this action has          
continued1 with more or less violence1  
for a certain  time1 it gradually       
moderates4 ,the evolution of bubbles    
slackens1 and  finally comes to an end2 
scum and lees alike settle at the       
bottom1 and  the fluid is once more     
clear and transparent4 ,but it has      

acquired  properties of which no trace  
existed in the original liquid4 ,instead
 of  being a mere sweet fluid1 mainly   
composed of sugar and water1 the sugar  
has more or less completely disappeared2
 and it has acquired that  peculiar     
smell and taste which we call           
spirituous4 ,instead of being  devoid of
 any obvious effect upon the animal     
economy1 it has become  possessed of a  
very wonderful influence on the nervous 
system2 so that in  small doses it      
exhilarates1 while in larger it         
stupefies1 and may even  destroy life4  
,moreover1 if the original fluid is put 
into a still1 and heated  moderately1   
the first and last product of its       
distillation is simple  water2 while1   
when the altered fluid is subjected to  
the same process1  the matter which is  
first condensed in the receiver is found
 to be a  clear1 volatile substance1    
which is lighter than water1 has a      
pungent  taste and smell1 possesses the 
intoxicating powers of the fluid in an  

eminent degree1 and takes fire the      
moment it is brought in contact with a  
flame4 ,the ,alchemists called this     
volatile liquid1 which they obtained    
from wine1 spirits of wine1 just as they
 called hydrochloric acid  spirits of   
salt1 and as we1 to this day1 call      
refined turpentine  spirits of          
turpentine4 ,as the spiritus1 or breath1
 of a man was  thought to be the most   
refined and subtle part of him1 the     
intelligent  essence of man was also    
conceived as a sort of breath1 or       
spirit2 and1 by  analogy1 the most      
refined essence of anything was called  
its spirit4  ,and thus it has come about
 that we use the same word for the soul 
of man  and for a glass of gin4    ,at  
the present day1 however1 we even more  
commonly use another name for  this     
peculiar liquid--namely1 alcohol1 and   
its origin is not less  singular4 ,the  
,dutch physician1 ,van ,helmont1 lived  
in the latter part of  the sixteenth and
 the beginning of the seventeenth       

century--in the  transition period      
between alchemy and chemistry--and was  
rather more  alchemist than chemist4    
,appended to his ,opera ,omnia1         
published in #agjg1  there is a very    
needful ,clavis ad obscuriorum sensum   
referendum1 in  which the following     
passage occurs4--                       
,,alcohol4--,chymicis est liquor aut    
pulvis summ subtilisatus1 vocabulo      
,orientalibus quoque1 cum primis        
,habessinis1 familiari1 quibus cohol    
speciatim pulverem impalpabilem ex      
antimonio pro oculis tingendis denotat  
444 ,hodie autem1 ob analogiam1 quivis  
pulvis tenerior ut pulvis oculorum      
cancri summ subtilisatus alcohol audit1 
haud aliter ac spiritus                 
rectificatissimi alcolisati dicuntur4   
,similarly1 ,robert ,boyle speaks of a  
fine powder as alcohol2 and1 so  late as
 the middle of the last century1 the    
,english lexicographer1 ,nathan         
,bailey1 defines alcohol as the pure    
substance of anything separated  from   

the more gross1 a very fine and         
impalpable powder1 or a very pure1      
well-rectified spirit4 ,but1 by the time
 of the publication of  ,lavoisier's    
,trait ,elmentaire de ,chimie1 in #aghi1
 the term alcohol1  alkohol1 or alkool  
7for it is spelt in all three ways71    
which ,van  ,helmont had applied        
primarily to a fine powder1 and only    
secondarily to  spirits of wine1 had    
lost its primary meaning altogether2    
and1 from the  end of the last century  
until now1 it has1 ,i believe1 been used
  exclusively as the denotation of      
spirits of wine1 and bodies chemically  
allied to that substance4    ,the       
process which gives rise to alcohol in a
 saccharine fluid is known  tones as    
fermentation2 a term based upon the     
apparent boiling up or  effervescence of
 the fermenting liquid1 and of ,latin   
origin4    ,our ,teutonic cousins call  
the same process ghren1 gsen1 gschen1   
and gischen2 but1 oddly enough1 we do   
not seem to have retained their  verb or

 their substantive denoting the action  
itself1 though we do use  names         
identical with1 or plainly derived from1
 theirs for the scum and  lees4 ,these  
are called1 in ,low ,german1 gscht and  
gischt2 in ,anglo-  ,saxon1 gest1 gist1 
and yst1 whence our yeast4 ,again1 in   
,low  ,german and in ,anglo-,saxon there
 is another name for yeast1 having the  
form barm1 or beorm2 and1 in the        
,midland ,counties1 barm is the name  by
 which yeast is still best known4 ,in   
,high ,german1 there is a third name    
for yeast1 hefe1 which is not           
represented in ,english1 so far as ,i   
know4    ,all these words are said by   
philologers to be derived from roots    
expressive of the intestine motion of a 
fermenting substance4 ,thus hefe  is    
derived from heben1 to raise2 barm from 
beren or bren1 to  bear up2 yeast1 yst1 
and gist1 have all to do with seething  
and  foam1 with yeasty waves1 and gusty 
breezes4    ,the same reference to the  
swelling up of the fermenting substance 

is seen  in the ,gallo-,latin terms     
levure and leaven4    ,it is highly     
creditable to the ingenuity of our      
ancestors that the  peculiar property of
 fermented liquids1 in virtue of which  
they make  glad the heart of man1 seems 
to have been known in the remotest      
periods  of which we have any record4   
,all savages take to alcoholic fluids as
 if  they were to the manner born4 ,our 
,vedic forefathers intoxicated          
themselves with the juice of the soma2  
,noah1 by a not unnatural  reaction     
against a superfluity of water1 appears 
to have taken the  earliest practicable 
opportunity of qualifying that which he 
was obliged  to drink2 and the ghosts of
 the ancient ,egyptians were solaced by 
pictures of banquets in which the       
wine-cup passes round1 graven on the    
walls of their tombs4 ,a knowledge of   
the process of fermentation1  therefore1
 was in all probability possessed by the
 prehistoric  populations of the globe2 
and it must have become a matter of     

great  interest even to primaeval       
wine-bibbers to study the methods by    
which  fermented liquids could be surely
 manufactured4 ,no doubt it was soon    
discovered that the most certain1 as    
well as the most expeditious1 way of    
making a sweet juice ferment was to add 
to it a little of the scum1 or  lees1 of
 another fermenting juice4 ,and it can  
hardly be questioned that  this singular
 excitation of fermentation in one      
fluid1 by a sort of  infection1 or      
inoculation1 of a little ferment taken  
from some other  fluid1 together with   
the strange swelling1 foaming1 and      
hissing of the  fermented substance1    
must have always attracted attention    
from the more  thoughtful4              
,nevertheless1 the commencement of the  
scientific analysis of  the phenomena   
dates from a period not earlier than the
 first half of the  seventeenth century4
    ,at this time1 ,van ,helmont made a 
first step1 by pointing out that the    
peculiar hissing and bubbling of a      

fermented liquid is due1 not to the     
evolution of common air 7which he1 as   
the inventor of the term gas1  calls gas
 ventosum71 but to that of a peculiar   
kind of air such as is  occasionally met
 with in caves1 mines1 and wells1 and   
which he calls gas  sylvestre4    ,but a
 century elapsed before the nature of   
this gas sylvestre1 or1 as  it was      
afterwards called1 fixed air1 was       
clearly determined1 and it was  found to
 be identical with that deadly          
choke-damp by which the lives of  those 
who descend into old wells1 or mines1 or
 brewers' vats1 are  sometimes suddenly 
ended2 and with the poisonous ariform   
fluid which is  produced by the         
combustion of charcoal1 and now goes by 
the name of  carbonic acid gas4         
,during the same time it gradually      
became evident that the presence of     
sugar was essential to the production of
 alcohol and the evolution of  carbonic 
acid gas1 which are the two great and   
conspicuous products of  fermentation4  

,and finally1 in #aghg1 the ,italian    
chemist1 ,fabroni1 made  the capital    
discovery that the yeast ferment1 the   
presence of which is  necessary to      
fermentation1 is what he termed a       
vegeto-animal substance2  that is1 a    
body which gives of ammoniacal salts    
when it is burned1 and  is1 in other    
ways1 similar to the gluten of plants   
and the albumen and  casein of animals4 
,these discoveries prepared the way for 
the illustrious ,frenchman1  ,lavoisier1
 who first approached the problem of    
fermentation with a  complete conception
 of the nature of the work to be done4  
,the words in  which he expresses this  
conception1 in the treatise on          
elementary  chemistry to which reference
 has already been made1 mark the year   
#aghi as  the commencement of a         
revolution of not less moment in the    
world of  science than that which       
simultaneously burst over the political 
world1  and soon engulfed ,lavoisier    
himself in one of its mad eddies4    ,we

 may lay it down as an incontestable    
axiom that1 in all the operations  of   
art and nature1 nothing is created2 an  
equal quantity of matter exists  both   
before1 and after the experiment3 the   
quality and quantity of the  elements   
remain precisely the same1 and nothing  
takes place beyond  changes and         
modifications in the combinations of    
these elements4 ,upon  this principle   
the whole art of performing chemical    
experiments depends2  we must always    
suppose an exact equality between the   
elements of the body  examined and those
 of the products of its analysis4       
,hence1 since from must of grapes we    
procure alcohol and carbonic acid1 ,i   
have an undoubted right to suppose that 
must consists of carbonic acid  and     
alcohol4 ,from these premisses we have  
two modes of ascertaining what  passes  
during vinous fermentation3 either by   
determining the nature of1  and the     
elements which compose1 the fermentable 
substances2 or by  accurately examining 

the products resulting from             
fermentation2 and it is  evident that   
the knowledge of either of these must   
lead to accurate  conclusions concerning
 the nature and composition of the      
other4 ,from  these considerations it   
became necessary accurately to determine
 the  constituent elements of the       
fermentable substances2 and for this    
purpose  ,i did not make use of the     
compound juices of fruits1 the rigorous 
analysis of which is perhaps impossible1
 but made choice of sugar1 which  is    
easily analysed1 and the nature of which
 ,i have already explained4  ,this      
substance is a true vegetable oxyd1 with
 two bases1 composed of  hydrogen and   
carbon1 brought to the state of an oxyd 
by means of a  certain proportion of    
oxygen2 and these three elements are    
combined in  such a way that a very     
slight force is sufficient to destroy   
the  equilibrium of their connection4   
,after giving the details of his        
analysis of sugar and of the products of

  fermentation1 ,lavoisier continues3-- 
,the effect of the vinous fermentation  
upon sugar is thus reduced to the  mere 
separation of its elements into two     
portions2 one part is oxygenated  at the
 expense of the other1 so as to form    
carbonic acid2 while the other  part1   
being disoxygenated in favour of the    
latter1 is converted into the           
combustible substance called alkohol2   
therefore1 if it were possible to       
re-unite alkohol and carbonic acid      
together1 we ought to form sugar4#a     
,footnote #a3 ,elements of ,chemistry4  
,by ,m4 ,lavoisier4 ,translated by      
,robert ,kerr4 ,second ,edition1 #agic  
7pp4 #ahf-aif74    ,thus ,lavoisier     
thought he had demonstrated that the    
carbonic acid and the  alcohol which are
 produced by the process of             
fermentation1 are equal in  weight to   
the sugar which disappears2 but the     
application of the more  refined methods
 of modern chemistry to the             
investigation of the products  of       

fermentation by ,pasteur1 in #ahfj1     
proved that this is not exactly  true1  
and that there is a deficit of from #e  
to #g per cent of the sugar  which is   
not covered by the alcohol and carbonic 
acid evolved4 ,the  greater part of this
 deficit is accounted for by the        
discovery of two  substances1 glycerine 
and succinic acid1 of the existence of  
which  ,lavoisier was unaware1 in the   
fermented liquid4 ,but about #a-a_/b per
 cent4  still remains to be made good4  
,according to ,pasteur1 it has been     
appropriated by the yeast1 but the fact 
that such appropriation takes  place    
cannot be said to be actually proved4   
,however this may be1 there can be no   
doubt that the constituent elements  of 
fully #ih per cent4 of the sugar which  
has vanished during fermentation  have  
simply undergone rearrangement2 like the
 soldiers of a brigade1 who  at the word
 of command divide themselves into the  
independent regiments  to which they    
belong4 ,the brigade is sugar1 the      

regiments are carbonic  acid1 succinic  
acid1 alcohol1 and glycerine4    ,from  
the time of ,fabroni1 onwards1 it has   
been admitted that the agent by  which  
this surprising rearrangement of the    
particles of the sugar is  effected is  
the yeast4 ,but the first thoroughly    
conclusive evidence of  the necessity of
 yeast for the fermentation of sugar was
 furnished by  ,appert1 whose method of 
preserving perishable articles of food  
excited so  much attention in ,france at
 the beginning of this century4         
,gay-,lussac1 in  his ,mmoire sur la    
,fermentation1#b alludes to ,appert's   
method of  preserving beer-wort         
unfermented for an indefinite time1 by  
simply  boiling the wort and closing the
 vessel in which the boiling fluid is   
contained1 in such a way as thoroughly  
to exclude air2 and he shows that1  if a
 little yeast be introduced into such   
wort1 after it has cooled1 the  wort at 
once begins to ferment1 even though     
every precaution be taken to  exclude   

air4 ,and this statement has since      
received full confirmation from         
,pasteur4    ,footnote #b3 ,annales de  
,chimie1 #ahaj4    ,on the other hand1  
,schwann1 ,schroeder and ,dutch1 and    
,pasteur1 have amply  proved that air   
may be allowed to have free access to   
beer-wort1 without  exciting            
fermentation1 if only efficient         
precautions are taken to prevent  the   
entry of particles of yeast along with  
the air4    ,thus1 the truth that the   
fermentation of a simple solution of    
sugar in  water depends upon the        
presence of yeast1 rests upon an        
unassailable  foundation2 and the       
inquiry into the exact nature of the    
substance which  possesses such a       
wonderful chemical influence becomes    
profoundly  interesting4    ,the first  
step towards the solution of this       
problem was made two  centuries ago by  
the patient and painstaking ,dutch      
naturalist1  ,leeuwenhoek1 who in the   
year #afhj wrote thus3--    ,saepissime 

examinavi fermnentum cerevisiae1        
semperque hoc ex globulis per  materiam 
pellucidam fluitantibus1 quarm          
cerevisiam esse censui1 constare        
observavi3 vidi etiam evidentissime1    
unumquemque hujus fermenti globulum     
denuo ex sex distinctis globulis        
constare1 accurate eidem quantitate et  
formae1 cui globulis sanguinis nostri1  
respondentibus4    ,verum talis mihi de 
horum origine et formatione conceptus   
formabam2  globulis nempe ex quibus     
farina ,tritici1 ,hordei1 ,avenae1      
,fagotritici1 se  constat aquae calore  
dissolvi et aquae commisceri2 hac1 vero 
aqua1 quam  cerevisiam vocare licet1    
refrigescente1 multos ex minimis        
particulis in  cerevisia coadunari1 et  
hoc pacto efficere particulam sive      
globulum1 quae  sexta pars est globuli  
faecis1 et iterum sex ex hisce globulis 
conjungi4#c    ,footnote #c3            
,leeuwenhoek1 ,arcana ,naturae ,detecta4
 ,ed4 ,nov41 #agba4    ,thus            
,leeuwenhoek discovered that yeast      

consists of globules floating in a      
fluid2 but he thought that they were    
merely the starchy particles of the     
grain from which the wort was made1     
rearranged4 ,he discovered the fact     
that yeast had a definite structure1 but
 not the meaning of the fact4 ,a        
century and a half elapsed1 and the     
investigation of yeast was  recommenced 
almost simultaneously by ,cagniard de la
 ,tour in ,france1 and  by ,schwann and 
,ktzing in ,germany4 ,the ,french       
observer was the first to  publish his  
results2 and the subject received at his
 hands and at those  of his colleague1  
the botanist ,turpin1 full and          
satisfactory  investigation4    ,the    
main conclusions at which they arrived  
are these4 ,the globular1 or  oval1     
corpuscles which float so thickly in the
 yeast as to make it muddy1  though the 
largest are not more than one           
two-thousandth of an inch in  diameter1 
and the smallest may measure less than  
one seven-thousandth of  an inch1 are   

living organisms4 ,they multiply with   
great rapidity by  giving off minute    
buds1 which soon attain the size of     
their parent1 and  then either become   
detached or remain united1 forming the  
compound  globules of which ,leeuwenhoek
 speaks1 though the constancy of their  
arrangement in sixes existed only in the
 worthy ,dutchman's imagination4    ,it 
was very soon made out that these yeast 
organisms1 to which ,turpin  gave the   
name of ,torula cerevisioe1 were more   
nearly allied to the  lower ,fungi than 
to anything else4 ,indeed ,turpin1 and  
subsequently  ,berkeley and ,hoffmann1  
believed that they had traced the       
development of  the ,torula into the    
well-known and very common mould--the   
,penicillium  glaucum4 ,other observers 
have not succeeded in verifying these   
statements2 and my own observations lead
 me to believe1 that while the          
connection between ,torula and the      
moulds is a very close one1 it is of  a 
different nature from that which has    

been supposed4 ,i have never been  able 
to trace the development of ,torula into
 a true mould2 but it is  quite easy to 
prove that species of true mould1 such  
as ,penicillium1  when sown in an       
appropriate nidus1 such as a solution of
 tartrate of  ammonia and yeast-ash1 in 
water1 with or without sugar1 give rise 
to  ,toruloe1 similar in all respects to
 ,t4 cerevisioe1 except that they  are1 
on the average1 smaller4 ,moreover1     
,bail has observed the development  of a
 ,torula larger than ,t4 cerevisioe1    
from a ,mucor1 a mould allied  to       
,penicillium4    ,it follows1 therefore1
 that the ,toruloe1 or organisms of     
yeast1 are  veritable plants2 and       
conclusive experiments have proved that 
the power  which causes the             
rearrangement of the molecules of the   
sugar is  intimately connected with the 
life and growth of the plant4 ,in fact1 
whatever arrests the vital activity of  
the plant also prevents it from         
exciting fermentation4    ,such being   

the facts with regard to the nature of  
yeast1 and the changes  which it effects
 in sugar1 how are they to be accounted 
for8 ,before  modern chemistry had come 
into existence1 ,stahl1 stumbling1 with 
the  stride of genius1 upon the         
conception which lies at the bottom of  
all  modern views of the process1 put   
forward the notion that the ferment1    
being in a state of internal motion1    
communicated that motion to the  sugar1 
and thus caused its resolution into new 
substances4 ,and ,lavoisier1  as we have
 seen1 adopts substantially the same    
view4 ,but ,fabroni1 full of  the then  
novel conception of acids and bases and 
double decompositions1  propounded the  
hypothesis that sugar is an oxide with  
two bases1 and the  ferment a carbonate 
with two bases2 that the carbon of the  
ferment unites  with the oxygen of the  
sugar1 and gives rise to carbonic acid2 
while the  sugar1 uniting with the      
nitrogen of the ferment1 produces a new 
substance  analogous to opium4 ,this is 

decomposed by distillation1 and gives   
rise to  alcohol4 ,next1 in #ahjc1      
,thnard propounded a hypothesis which   
partakes  somewhat of the nature of both
 ,stahl's and ,fabroni's views4 ,i do   
not  believe with ,lavoisier1 he says1  
that all the carbonic acid formed       
proceeds from the sugar4 ,how1 in that  
case1 could we conceive the action  of  
the ferment on it8 ,i think that the    
first portions of the acid are due  to a
 combination of the carbon of the       
ferment with the oxygen of the  sugar1  
and that it is by carrying off a portion
 of oxygen from the last  that the      
ferment causes the fermentation to      
commence--the equilibrium  between the  
principles of the sugar being disturbed1
 they combine afresh  to form carbonic  
acid and alcohol4    ,the three views   
here before us may be familiarly        
exemplified by supposing  the sugar to  
be a card-house4 ,according to ,stahl1  
the ferment is somebody  who knocks the 
table1 and shakes the card-house down2  

according to  ,fabroni1 the ferment     
takes out some cards1 but puts others in
 their  places2 according to ,thnard1   
the ferment simply takes a card out of  
the  bottom story1 the result of which  
is that all the others fall4    ,as     
chemistry advanced1 facts came to light 
which put a new face upon  ,stahl's     
hypothesis1 and gave it a safer         
foundation than it previously           
possessed4 ,the general nature of these 
phenomena may be thus stated3--,a  body1
 ,a1 without giving to1 or taking from1 
another body ,b1 any material           
particles1 causes ,b to decompose into  
other substances1 ,c1 ,d1 ,e1 the sum   
of the weights of which is equal to the 
weight of ,b1 which decomposes4  ,thus1 
bitter almonds contain two substances1  
amygdalin and synaptase1  which can be  
extracted1 in a separate state1 from the
 bitter almonds4 ,the  amygdalin thus   
obtained1 if dissolved in water1        
undergoes no change2 but  if a little   
synaptase be added to the solution1 the 

amygdalin splits up  into bitter almond 
oil1 prussic acid1 and a kind of sugar4 
,a short time after ,cagniard de la     
,tour discovered the yeast plant1       
,liebig1 struck with the similarity     
between this and other such processes   
and the fermentation of sugar1 put      
forward the hypothesis that yeast       
contains a substance which acts upon    
sugar1 as synaptase acts upon           
amygdalin4 ,and as the synaptase is     
certainly neither organized nor alive1  
but a mere chemical substance1 ,liebig  
treated ,cagniard de la ,tour's         
discovery with no small contempt1 and1  
from that time to the present1 has      
steadily repudiated the notion that the 
decomposition of the sugar is1 in  any  
sense1 the result of the vital activity 
of the ,torula4 ,but1 though  the notion
 that the ,torula is a creature which   
eats sugar and excretes  carbonic acid  
and alcohol1 which is not unjustly      
ridiculed in the most  surprising paper 
that ever made its appearance in a grave

 scientific  journal1#d may be          
untenable1 the fact that the ,toruloe   
are alive1 and  that yeast does not     
excite fermentation unless it contains  
living  ,toruloe1 stands fast4          
,moreover1 of late years1 the essential 
participation of living organisms in    
fermentation other than the  alcoholic1 
has been clearly made out by ,pasteur   
and other chemists4    ,footnote #d3    
,das entrthselte ,geheimniss der        
geistigen ,ghrung  7,vorlnfige          
briefliche ,mittheilung7 is the title of
 an anonymous  contribution to ,whler   
and ,liebig's ,annalen der ,pharmacie   
for #ahci1 in  which a somewhat         
,rabelaisian imaginary description of   
the organisation of  the yeast animals  
and of the manner in which their        
functions are  performed1 is given with 
a circumstantiality worthy of the author
 of  ,gulliver's ,travels4 ,as a        
specimen of the writer's humour1 his    
account  of what happens when           
fermentation comes to an end may        

suffice4 ,sobald  nmlich die ,thiere    
keinen ,zucker mehr vorfinden1 so       
fressen sie sich  gegenseitig selbst    
auf1 was durch eine eigene ,manipulation
 geschieht2  alles wird verdant bis auf 
die ,eier1 welche unverndert durch den  
,darmkanal hineingehen2 man hat zuletzt 
wieder ghrungsfhige ,hefe1  nmlich den  
,saamen der ,thiere1 der brig bleibt4   
,however1 it may be  asked1 is there any
 necessary opposition between the       
so-called vital  and the strictly       
physico-chemical views of fermentation8 
,it is quite  possible that the living  
,torula may excite fermentation in      
sugar1  because it constantly produces1 
as an essential part of its vital       
manifestations1 some substance which    
acts upon the sugar1 just as the        
synaptase acts upon the amygdalin4 ,or  
it may be1 that1 without the  formation 
of any such special substance1 the      
physical condition of the  living tissue
 of the yeast plant is sufficient to    
effect that small  disturbance of the   

equilibrium of the particles of the     
sugar1 which  ,lavoisier thought        
sufficient to effect its decomposition4 
,platinum in a very fine state of       
division--known as platinum black1 or   
noir de platine--has the very singular  
property of causing alcohol to  change  
into acetic acid with great rapidity4   
,the vinegar plant1 which is  closely   
allied to the yeast plant1 has a similar
 effect upon dilute  alcohol1 causing it
 to absorb the oxygen of the air1 and   
become converted  into vinegar2 and     
,liebig's eminent opponent1 ,pasteur1   
who has done so  much for the theory and
 the practice of vinegar-making1 himself
 suggests  that in this case--    ,la   
cause du phnomne physique qui accompagne
 la vie de la plante rside  dans un tat 
physique propre1 analogue  celui du noir
 de platine4 ,mais  il est essentiel de 
remarquer que cet tat physique de la    
plante est  troitement li avec la vie de
 cette plante4#e    ,footnote #e3       
,etudes sur les ,mycodermes1            

,comptes-,rendus1 liv41 #ahfb4    ,now1 
if the vinegar plant gives rise to the  
oxidation of alcohol1 on  account of its
 merely physical constitution1 it is at 
any rate possible  that the physical    
constitution of the yeast plant may     
exert a decomposing  influence on sugar4
    ,but1 without presuming to discuss a
 question which leads us into the very  
arcana of chemistry1 the present state  
of speculation upon the modus  operandi 
of the yeast plant in producing         
fermentation is represented1 on  the one
 hand1 by the ,stahlian doctrine1       
supported by ,liebig1 according to      
which the atoms of the sugar are shaken 
into new combinations either  directly  
by the ,toruloe1 or indirectly1 by some 
substance formed by  them2 and1 on the  
other hand1 by the ,thnardian doctrine1 
supported by  ,pasteur1 according to    
which the yeast plant assimilates part  
of the  sugar1 and1 in so doing1        
disturbs the rest1 and determines its   
resolution  into the products of        

fermentation4 ,perhaps the two views are
 not so much  opposed as they seem at   
first sight to be4    ,but the interest 
which attaches to the influence of the  
yeast plants upon  the medium in which  
they live and grow does not arise solely
 from its  bearing upon the theory of   
fermentation4 ,so long ago as #ahch1    
,turpin  compared the ,toruloe to the   
ultimate elements of the tissues of     
animals  and plants--,les organes       
lmentaires de leurs tissus1 comparables 
aux  petits vgtaux des levures          
ordinaires1 sont aussi les dcompositeurs
 des  substances qui les environnent4   
,almost at the same time1 and1 probably1
 equally guided by his study of  yeast1 
,schwann was engaged in those remarkable
 investigations into the  form and      
development of the ultimate structural  
elements of the tissues  of animals1    
which led him to recognise their        
fundamental identity with  the ultimate 
structural elements of vegetable        
organisms4    ,the yeast plant is a mere

 sac1 or cell1 containing a semi-fluid  
matter1  and ,schwann's microscopic     
analysis resolved all living organisms1 
in the  long run1 into an aggregation of
 such sacs or cells1 variously modified2
  and tended to show1 that all1 whatever
 their ultimate complication1 begin     
their existence in the condition of such
 simple cells4    ,in his famous        
,mikroskopische ,untersuchungen ,schwann
 speaks of ,torula  as a cell2 and1 in a
 remarkable note to the passage in which
 he refers  to the yeast plant1 ,schwann
 says3--    ,i have been unable to avoid
 mentioning fermentation1 because it is 
the  most fully and exactly known       
operation of cells1 and represents1 in  
the  simplest fashion1 the process which
 is repeated by every cell of the       
living body4    ,in other words1        
,schwann conceives that every cell of   
the living body  exerts an influence on 
the matter which surrounds and permeates
 it1  analogous to that which a ,torula 
exerts on the saccharine solution by    

which it is bathed4 ,a wonderfully      
suggestive thought1 opening up views of 
the nature of the chemical processes of 
the living body1 which have  hardly yet 
received all the development of which   
they are capable4    ,kant defined the  
special peculiarity of the living body  
to be that the  parts exist for the sake
 of the whole and the whole for the sake
 of the  parts4 ,but when ,turpin and   
,schwann resolved the living body into  
an  aggregation of quasi-independent    
cells1 each1 like a ,torula1 leading    
its own life and having its own laws of 
growth and development1 the  aggregation
 being dominated and kept working       
towards a definite end only  by a       
certain harmony among these units1 or by
 the superaddition of a  controlling    
apparatus1 such as a nervous system1    
this conception ceased  to be tenable4  
,the cell lives for its own sake1 as    
well as for the sake  of the whole      
organism2 and the cells which float in  
the blood1 live at  its expense1 and    

profoundly modify it1 are almost as much
 independent  organisms as the ,toruloe 
which float in beer-wort4    ,schwann   
burdened his enunciation of the cell    
theory with two false  suppositions2 the
 one1 that the structures he called     
nucleus#f and  cell-wall are essential  
to a cell2 the other1 that cells are    
usually  formed independently of other  
cells2 but1 in #ahci1 it was a vast and 
clear gain to arrive at the conception1 
that the vital functions of all  the    
higher animals and plants are the       
resultant of the forces inherent in  the
 innumerable minute cells of which they 
are composed1 and that each of  them is1
 itself1 an equivalent of one of the    
lowest and simplest of  independent     
living beings--the ,torula4    ,footnote
 #f3 ,later investigations have thrown  
an entirely new light upon  the         
structure and the functional importance 
of the nucleus2 and have  proved that   
,schwann did not over-estimate its      
importance4 #ahid4    ,from purely      

morphological investigations1 ,turpin   
and ,schwann1 as we have  seen1 arrived 
at the notion of the fundamental unity  
of structure of  living beings4 ,and1   
before long1 the researches of chemists 
gradually led  up to the conception of  
the fundamental unity of their          
composition4    ,so far back as #ahjc1  
,thnard pointed out1 in most distinct   
terms1 the  important fact that yeast   
contains a nitrogenous animal substance2
 and  that such a substance is contained
 in all ferments4 ,before him1 ,fabroni 
and ,fourcroy speak of the vegeto-animal
 matter of yeast4 ,in #ahdd ,mulder     
endeavoured to demonstrate that a       
peculiar substance1 which he called     
protein1 was essentially characteristic 
of living matter4    ,in #ahdf1 ,payen  
writes3--    ,enfin1 une loi sans       
exception me semble apparatre dans les  
faits  nombreux que j'ai observs et     
conduire  envisager sous un nouveau jour
  la vie vgtale2 si je ne m'abuse1 tout 
ce que dans les tissus vgtaux  la vue   

directe o amplifie nous permet de       
discerner sous la forme de  cellules et 
de vaisseaux1 ne reprsente autre chose  
que les enveloppes  protectrices1 les   
rservoirs et les conduits1  l'aide      
desquels les corps  anims qui les       
secrtent et les faonnent1 se logent1    
puisent et  charrient leurs aliments1   
dposent et isolent les matires excrtes4 
,and again3--    ,afin de complter      
aujourd'hui l'nonc du fait gnral1 je    
rappellerai  que les corps1 dou des     
fonctions accomplies dans les tissus des
 plantes1  sont forms des lments qui    
constituent1 en proportion peu variable1
 les  organismes animaux2 qu'ainsi l'on 
est conduit  reconnatre une immense     
unit de composition lmentaire dans tous 
les corps vivants de la  nature4#g      
,footnote #g3 ,mm4 sur les              
,dveloppements des ,vgtaux1 c4--,mm4    
,prsentes4 ix4 #ahdf4    ,in the year   
7#ahdf7 in which these remarkable       
passages were published1 the  eminent   
,german botanist1 ,von ,mohl invented   

the word protoplasm1 as a  name for one 
portion of those nitrogenous contents of
 the cells of living  plants1 the close 
chemical resemblance of which to the    
essential  constituents of living       
animals is so strongly indicated by     
,payen4 ,and  through the twenty-five   
years that have passed1 since the matter
 of life  was first called protoplasm1 a
 host of investigators1 among whom      
,cohn1  ,max ,schulze1 and ,khne must be
 named as leaders1 have accumulated     
evidence1 morphological1 physiological1 
and chemical1 in favour of that  immense
 unit de composition lmentaire dans tous
 les corps vivants de  la nature1 into  
which ,payen had1 so early1 a clear     
insight4    ,as far back as #ahej1 ,cohn
 wrote1 apparently without any knowledge
 of what  ,payen had said before him3-- 
,the protoplasm of the botanist1 and the
 contractile substance and  sarcode of  
the zoologist1 must be1 if not          
identical1 yet in a high degree         
analogous substances4 ,hence1 from this 

point of view1 the difference  between  
animals and plants consists in this2    
that1 in the latter1 the  contractile   
substance1 as a primordial utricle1 is  
enclosed within an  inert cellulose     
membrane1 which permits it only to      
exhibit an internal  motion1 expressed  
by the phenomena of rotation and        
circulation1 while1 in  the former1 it  
is not so enclosed4 ,the protoplasm in  
the form of the  primordial utricle is1 
as it were1 the animal element in the   
plant1 but  which is imprisoned1 and    
only becomes free in the animal2 or1 to 
strip  off the metaphor which obscures  
simple thought1 the energy of organic   
vitality which is manifested in movement
 is especially exhibited by a           
nitrogenous contractile substance1 which
 in plants is limited and  fettered by  
an inert membrane1 in animals not so4#h 
,footnote #h3 ,cohn1 ,ueber ,protococcus
 pluvialis1 in the ,nova ,acta for      
#ahej4    ,in #ahfh1 thinking that an   
untechnical statement of the views      

current  among the leaders of biological
 science might be interesting to the    
general public1 ,i gave a lecture       
embodying them in ,edinburgh4 ,those who
  have not made the mistake of          
attempting to approach biology1 either  
by  the high  priori road of mere       
philosophical speculation1 or by the    
mere low  posteriori lane offered by the
 tube of a microscope1 but  have taken  
the trouble to become acquainted with   
well-ascertained facts  and with their  
history1 will not need to be told that  
in what ,i had to  say as regards       
protoplasm in my lecture ,on the        
,physical ,basis of ,life  7,vol4 ,i4 of
 these ,essays1 p4 #acj71 there was     
nothing new2 and1 as ,i hope1  nothing  
that the present state of knowledge does
 not justify us in  believing to be     
true4 ,under these circumstances1 my    
surprise may be  imagined1 when ,i      
found1 that the mere statement of facts 
and of views1  long familiar to me as   
part of the common scientific property  

of  ,continental workers1 raised a sort 
of storm in this country1 not only by   
exciting the wrath of unscientific      
persons whose pet prejudices they       
seemed to touch1 but by giving rise to  
quite superfluous explosions on  the    
part of some who should have been better
 informed4    ,dr4 ,stirling1 for       
example1 made my essay the subject of a 
special  critical lecture1#i which ,i   
have read with much interest1 though1 ,i
  confess1 the meaning of much of it    
remains as dark to me as does the       
,secret of ,hegel after ,dr4 ,stirling's
 elaborate revelation of it4 ,dr4       
,stirling's method of dealing with the  
subject is peculiar4 ,protoplasm  is a  
question of history1 so far as it is a  
name2 of fact1 so far as it  is a thing4
 ,dr4 ,stirling1 has not taken the      
trouble to refer to the  original       
authorities for his history1 which is   
consequently a travesty2  and still less
 has he concerned himself with looking  
at the facts1 but  contents himself with

 taking them also at second-hand4 ,a    
most amusing  example of this fashion of
 dealing with scientific statements is  
furnished by ,dr4 ,stirling's remarks   
upon my account of the protoplasm of    
the nettle hair4 ,that account was drawn
 up from careful and often-  repeated   
observation of the facts4 ,dr4 ,stirling
 thinks he is offering a  valid         
criticism1 when he says that my valued  
friend ,professor ,stricker  gives a    
somewhat different statement about      
protoplasm4 ,but why in the  world did  
not this distinguished ,hegelian look at
 a nettle hair for  himself1 before     
venturing to speak about the matter at  
all8 ,why trouble  himself about what   
either ,stricker or ,i say1 when any    
tyro can see the  facts for himself1 if 
he is provided with those not rare      
articles1 a  nettle and a microscope8   
,but ,i suppose this would have been    
,aufklrung--a recurrence to the base    
common-sense philosophy of the          
eighteenth century1 which liked to see  

before it believed1 and to  understand  
before it criticised ,dr4 ,stirling     
winds up his paper with the  following  
paragraph3--    ,footnote #i3           
,subsequently published under the title 
of ,as regards  ,protoplasm4    ,in     
short1 the whole position of ,mr4       
,huxley1 7#a7 that all organisms        
consist alike of the same life-matter1  
7#b7 which life-matter is1 for its      
part1 due only to chemistry1 must be    
pronounced untenable--nor less          
untenable 7#c7 the materialism he would 
found on it4    ,the paragraph contains 
three distinct assertions concerning my 
views1 and  just the same number of     
utter misrepresentations of them4 ,that 
which ,i  have numbered 7#a7 turns on   
the ambiguity of the word same1 for a   
discussion of which ,i would refer ,dr4 
,stirling to a great hero of  ,aufklrung
 ,archbishop ,whately2 statement number 
7#b7 is1 in my  judgment1 absurd1 and   
certainly ,i have never said anything   
resembling it2  while1 as to number     

7#c71 one great object of my essay was  
to show that  what is called materialism
 has no sound philosophical basis6      
,as we have seen1 the study of yeast has
 led investigators face to face  with   
problems of immense interest in pure    
chemistry1 and in animal and  vegetable 
morphology4 ,its physiology is not less 
rich in subjects for  inquiry4 ,take1   
for example1 the singular fact that     
yeast will increase  indefinitely when  
grown in the dark1 in water containing  
only tartrate of  ammonia a small       
percentage of mineral salts and sugar4  
,out of these  materials the ,toruloe   
will manufacture nitrogenous protoplasm1
  cellulose1 and fatty matters1 in any  
quantity1 although they are wholly      
deprived of those rays of the sun1 the  
influence of which is essential to  the 
growth of ordinary plants4 ,there has   
been a great deal of speculation        
lately1 as to how the living organisms  
buried beneath two or three  thousand   
fathoms of water1 and therefore in all  

probability almost  deprived of light1  
live4 ,if any of them possess the same  
powers as yeast  7and the same capacity 
for living without light is exhibited by
 some  other fungi7 there would seem to 
be no difficulty about the matter4      
,of the pathological bearings of the    
study of yeast1 and other such          
organisms1 ,i have spoken elsewhere4 ,it
 is certain that1 in some animals1      
devastating epidemics are caused by     
fungi of low order--similar to those  of
 which ,torula is a sort of offshoot4   
,it is certain that such diseases  are  
propagated by contagion and infection1  
in just the same way as  ordinary       
contagious and infectious diseases are  
propagated4 ,of course1 it  does not    
follow from this1 that all contagious   
and infectious diseases  are caused by  
organisms of as definite and independent
 a character as the  ,torula2 but1 ,i   
think1 it does follow that it is prudent
 and wise to  satisfy one's self in each
 particular case1 that the germ theory  

cannot  and will not explain the facts1 
before having recourse to hypotheses    
which have no equal support from        
analogy4        ,v      ,,on ,,the      
,,formation ,,of ,,coal    #ahgj    ,the
 lumps of coal in a coal-scuttle very   
often have a roughly cubical  form4 ,if 
one of them be picked out and examined  
with a little care1 it  will be found   
that its six sides are not exactly      
alike4 ,two opposite  sides are         
comparatively smooth and shining1 while 
the other four are much  rougher1 and   
are marked by lines which run parallel  
with the smooth  sides4 ,the coal       
readily splits along these lines1 and   
the split surfaces  thus formed are     
parallel with the smooth faces4 ,in     
other words1 there is  a sort of rough  
and incomplete stratification in the    
lump of coal1 as if  it were a book1 the
 leaves of which had stuck together very
 closely4    ,sometimes the faces along 
which the coal splits are not smooth1   
but  exhibit a thin layer of dull1      

charred-looking substance1 which is     
known  as mineral charcoal4             
,occasionally one of the faces of a lump
 of coal will present impressions1      
which are obviously those of the stem1  
or leaves1 of a plant2 but though  hard 
mineral masses of pyrites1 and even fine
 mud1 may occur here and  there1 neither
 sand nor pebbles are met with4    ,when
 the coal burns1 the chief ultimate     
products of its combustion are  carbonic
 acid1 water1 and ammoniacal products1  
which escape up the  chimney2 and a     
greater or less amount of residual      
earthy salts1 which  take the form of   
ash4 ,these products are1 to a great    
extent1 such as  would result from the  
burning of so much wood4    ,these      
properties of coal may be made out      
without any very refined  appliances1   
but the microscope reveals something    
more4 ,black and opaque  as ordinary    
coal is1 slices of it become transparent
 if they are cemented  in ,canada       
balsam1 and rubbed down very thin1 in   

the ordinary way of  making thin        
sections of non-transparent bodies4 ,but
 as the thin slices1  made in this way1 
are very apt to crack and break into    
fragments1 it is  better to employ      
marine glue as the cementing material4  
,by the use of  this substance1 slices  
of considerable size and of extreme     
thinness and  transparency may be       
obtained4#a    ,footnote #a3 ,my        
assistant in the ,museum of ,practical  
,geology1 ,mr4 ,newton1  invented this  
excellent method of obtaining thin      
slices of coal4    ,now let us suppose  
two such slices to be prepared from our 
lump of coal--  one parallel with the   
bedding1 the other perpendicular to it2 
and let us  call the one the horizontal1
 and the other the vertical1 section4   
,the  horizontal section will present   
more or less rounded yellow patches and 
streaks1 scattered irregularly through  
the dark brown1 or blackish1  ground    
substance2 while the vertical section   
will exhibit mere elongated  bars and   

granules of the same yellow materials1  
disposed in lines which  correspond1    
roughly1 with the general direction of  
the bedding of the  coal4    ,this is   
the microscopic structure of an ordinary
 piece of coal4 ,but if a  great series 
of coals1 from different localities and 
seams1 or even from  different parts of 
the same seam1 be examined1 this        
structure will be  found to vary in two 
directions4 ,in the anthracitic1 or     
stone-coals1  which burn like coke1 the 
yellow matter diminishes1 and the ground
  substance becomes more predominant1   
blacker1 and more opaque1 until it      
becomes impossible to grind a section   
thin enough to be translucent2  while1  
on the other hand1 in such as the       
,better-,bed coal of the  neighbourhood 
of ,bradford1 which burns with much     
flame1 the coal is of a  far lighter1   
colour and transparent sections are very
 easily obtained4 ,in  the browner parts
 of this coal1 sharp eyes will readily  
detect multitudes  of curious little    

coin-shaped bodies1 of a yellowish brown
 colour1  embedded in the dark brown    
ground substance4 ,on the average1 these
 little  brown bodies may have a        
diameter of about one-twentieth of an   
inch4 ,they  lie with their flat        
surfaces nearly parallel with the two   
smooth faces of  the block in which they
 are contained2 and1 on one side of     
each1 there  may be discerned a figure1 
consisting of three straight linear     
marks1  which radiate from the centre of
 the disk1 but do not quite reach its   
circumference4 ,in the horizontal       
section these disks are often converted 
into more or less complete rings2 while 
in the vertical sections they  appear   
like thick hoops1 the sides of which    
have been pressed together4  ,the disks 
are1 therefore1 flattened bags2 and     
favourable sections show  that the      
three-rayed marking is the expression of
 three clefts1 which  penetrate one wall
 of the bag4    ,the sides of the bags  
are sometimes closely approximated2 but1

 when the  bags are less flattened1     
their cavities are1 usually1 filled with
  numerous1 irregularly rounded1 hollow 
bodies1 having the same kind of  wall as
 the large ones1 but not more than one  
seven-hundredth of an inch  in diameter4
    ,in favourable specimens1 again1    
almost the whole ground substance       
appears  to be made up of similar       
bodies--more or less carbonized or      
blackened--  and1 in these1 there can be
 no doubt that1 with the exception of   
patches  of mineral charcoal1 here and  
there1 the whole mass of the coal is    
made  up of an accumulation of the      
larger and of the smaller sacs4    ,but1
 in one and the same slice1 every       
transition can be observed from  this   
structure to that which has been        
described as characteristic of  ordinary
 coal4 ,the latter appears to rise out  
of the former1 by the  breaking-up and  
increasing carbonization of the larger  
and the smaller  sacs4 ,and1 in the     
anthracitic coals1 this process appears 

to have gone to  such a length1 as to   
destroy the original structure          
altogether1 and to  replace it by a     
completely carbonized substance4        
,thus coal may be said1 speaking        
broadly1 to be composed of two          
constituents3 firstly1 mineral charcoal2
 and1 secondly1 coal proper4 ,the       
nature of the mineral charcoal has long 
since been determined4 ,its  structure  
shows it to consist of the remains of   
the stems and leaves of  plants1 reduced
 a little more than their carbon4       
,again1 some of the coal  is made up of 
the crushed and flattened bark1 or outer
 coat1 of the stems  of plants1 the     
inner wood of which has completely      
decayed away4 ,but what  ,i may term the
 saccular matter of the coal1 which1    
either in its  primary or in its        
degraded form constitutes by far the    
greater part of  all the bituminous     
coals ,i have examined1 is certainly not
 mineral  charcoal2 nor is its structure
 that of any stem or leaf4 ,hence its   

real  nature is at first by no means    
apparent1 and has been the subject of   
much  discussion4    ,the first person  
who threw any light upon the problem1 as
 far as ,i have  been able to discover1 
was the well-known geologist1 ,professor
 ,morris4 ,it  is now thirty-four years 
since he carefully described and figured
 the  coin-shaped bodies1 or larger     
sacs1 as ,i have called them1 in a note 
appended to the famous paper ,on the    
,coalbrookdale ,coal-,field1 published  
at that time1 by the present ,president 
of the ,geological ,society1 ,mr4       
,prestwich4 ,with much sagacity1        
,professor ,morris divined the real     
nature  of these bodies1 and boldly     
affirmed them to be the spore-cases of a
  plant allied to the living            
club-mosses4    ,but discovery sometimes
 makes a long halt2 and it is only a few
 years  since ,mr4 ,carruthers          
determined the plant 7or rather one of  
the plants7  which produces these       
spore-cases1 by finding the discoidal   

sacs still  adherent to the leaves of   
the fossilized cone which produced them4
 ,he  gave the name of ,flemingites     
gracilis to the plant of which the cones
  form a part4 ,the branches and stem of
 this plant are not yet certainly       
known1 but there is no sort of doubt    
that it was closely allied to the       
,lepidodendron1 the remains of which    
abound in the coal formation4 ,the      
,lepidodendra were shrubs and trees     
which put one more in mind of an        
,araucaria than of any other familiar   
plant2 and the ends of the  fruiting    
branches were terminated by cones1 or   
catkins1 somewhat like the  bodies so   
named in a fir1 or a willow4 ,these     
conical fruits1 however1 did  not       
produce seeds2 but the leaves of which  
they were composed bore upon  their     
surfaces sacs full of spores or         
sporangia1 such as those one sees  on   
the under surface of a bracken leaf4    
,now1 it is these sporangia of the      
,lepidodendroid plant ,flemingites which

 were identified by ,mr4  ,carruthers   
with the free sporangia described by    
,professor ,morris1 which  are the same 
as the large sacs of which ,i have      
spoken4 ,and1 more than  this1 there is 
no doubt that the small sacs are the    
spores1 which were  originally contained
 in the sporangia4    ,the living       
club-mosses are1 for the most part1     
insignificant and creeping  herbs1      
which1 superficially1 very closely      
resemble true mosses1 and none  of them 
reach more than two or three feet in    
height4 ,but1 in their  essential       
structure1 they very closely resemble   
the earliest  ,lepidodendroid trees of  
the coal3 their stems and leaves are    
similar2 so  are their cones2 and no    
less like are the sporangia and spores2 
while  even in their size1 the spores of
 the ,lepidodendron and those of the    
existing ,lycopodium1 or club-moss1 very
 closely approach one another4    ,thus1
 the singular conclusion is forced upon 
us1 that the greater and the  smaller   

sacs of the ,better-,bed and other      
coals1 in which the primitive  structure
 is well preserved1 are simply the      
sporangia and spores of  certain plants1
 many of which were closely allied to   
the existing club-  mosses4 ,and if1 as 
,i believe1 it can be demonstrated that 
ordinary coal  is nothing but saccular  
coal which has undergone a certain      
amount of  that alteration which1 if    
continued1 would convert it into        
anthracite2  then1 the conclusion is    
obvious1 that the great mass of the coal
 we burn  is the result of the          
accumulation of the spores and          
spore-cases of  plants1 other parts of  
which have furnished the carbonized     
stems and the  mineral charcoal1 or have
 left their impressions on the surfaces 
of the  layer4    ,of the multitudinous 
speculations which1 at various times1   
have been  entertained respecting the   
origin and mode of formation of coal1   
several  appear to be negatived1 and put
 out of court1 by the structural facts  

the  significance of which ,i have      
endeavoured to explain4 ,these facts1   
for  example1 do not permit us to       
suppose that coal is an accumulation of 
peaty matter1 as some have held4        
,again1 the late ,professor ,quekett was
 one of the first observers who gave  a 
correct description of what ,i have     
termed the saccular structure of  coal2 
and1 rightly perceiving that this       
structure was something quite  different
 from that of any known plant1 he       
imagined that it proceeded  from some   
extinct vegetable organism which was    
peculiarly abundant  amongst the        
coal-forming plants4 ,but this          
explanation is at once shown to  be     
untenable when the smaller and the      
larger sacs are proved to be spores  or 
sporangia4    ,some1 once more1 have    
imagined that coal was of submarine     
origin2 and  though the notion is amply 
and easily refuted by other             
considerations1 it  may be worth while  
to remark1 that it is impossible to     

comprehend how a  mass of light and     
resinous spores should have reached the 
bottom of the  sea1 or should have      
stopped in that position if they had got
 there4    ,at the same time1 it is     
proper to remark that ,i do not presume 
to suggest  that all coal must needs    
have the same structure2 or that there  
may not  be coals in which the          
proportions of wood and spores1 or      
spore-cases1 are  very different from   
those which ,i have examined4 ,all ,i   
repeat is1 that  none of the coals which
 have come under my notice have enabled 
me to  observe such a difference4 ,but1 
according to ,principal ,dawson1 who has
 so  sedulously examined the fossil     
remains of plants in ,north ,america1 it
 is  otherwise with the vast            
accumulations of coal in that country4  
,the true coal1 says ,dr4 ,dawson1      
consists principally of the flattened   
bark of ,sigillarioid and other trees1  
intermixed with leaves of ,ferns and    
,cordaites1 and other herbaceous dbris1 

and with fragments of decayed  wood1    
constituting 'mineral charcoal1' all    
these materials having  manifestly alike
 grown and accumulated where we find    
them4#b    ,footnote #b3 ,acadian       
,geology1 #bnd edition1 p4 #ace4        
,when ,i had the pleasure of seeing     
,principal ,dawson in ,london last      
summer1  ,i showed him my sections of   
coal1 and begged him to re-examine some 
of  the ,american coals on his return to
 ,canada1 with an eye to the presence   
of spores and sporangia1 such as ,i was 
able to show him in our ,english  and   
,scotch coals4 ,he has been good enough 
to do so2 and in a letter dated         
,september #bfth1 #ahgj1 he informs me  
that--    ,indications of spore-cases   
are rare1 except in certain coarse shaly
  coals and portions of coals1 and in   
the roofs of the seams4 ,the most       
marked case ,i have yet met with is the 
shaly coal referred to as  containing   
,sporangites in my paper on the         
conditions of accumulation of  coal     

7,journal of the ,geological ,society1  
vol4 xxii4 pp4 #aae1 #aci1 and  #afe74  
,the purer coals certainly consist      
principally of cubical tissues  with    
some true woody matter1 and the         
spore-cases1 c41 are chiefly in the     
coarse and shaly layers4 ,this is my old
 doctrine in my two papers in the       
,journal of the ,geological ,society1   
and ,i see nothing to modify it4 ,your  
observations1 however1 make it probable 
that the frequent clear spots  in the   
cannels are spore-cases4    ,dr4        
,dawson's results are the more          
remarkable1 as the numerous specimens   
of ,british coal1 from various          
localities1 which ,i have examined1 tell
 one  tale as to the predominance of the
 spore and sporangium element in their  
composition2 and as it is exactly in the
 finest and purest coals1 such as  the  
,better-,bed coal of ,lowmoor1 that the 
spores and sporangia obviously          
constitute almost the entire mass of the
 deposit4    ,coal1 such as that which  

has been described1 is always found in  
sheets1  or seams1 varying from a       
fraction of an inch to many feet in     
thickness1  enclosed in the substance of
 the earth at very various depths1      
between  beds of rock of different      
kinds4 ,as a rule1 every seam of coal   
rests upon  a thicker1 or thinner1 bed  
of clay1 which is known as under-clay4  
,these  alternations of beds of coal1   
clay1 and rock may be repeated many     
times1  and are known as the            
coal-measures2 and in some regions1 as  
in ,south  ,wales and in ,nova ,scotia1 
the coal-measures attain a thickness of 
twelve  or fourteen thousand feet1 and  
enclose eighty or a hundred seams of    
coal1  each with its under-clay1 and    
separated from those above and below by 
beds of sandstone and shale4    ,the    
position of the beds which constitute   
the coal-measures is infinitely         
diverse4 ,sometimes they are tilted up  
vertically1 sometimes they are          
horizontal1 sometimes curved into great 

basins2 sometimes they come to  the     
surface1 sometimes they are covered up  
by thousands of feet of rock4  ,but1    
whatever their present position1 there  
is abundant and conclusive  evidence    
that every under-clay was once a surface
 soil4 ,not only do  carbonized         
root-fibres frequently abound in these  
under-clays2 but the  stools of trees1  
the trunks of which are broken off and  
confounded with  the bed of coal1 have  
been repeatedly found passing into      
radiating roots1  still embedded in the 
under-clay4 ,on many parts of the coast 
of ,england1  what are commonly known as
 submarine forests are to be seen at low
  water4 ,they consist1 for the most    
part1 of short stools of oak1 beech1    
and fir-trees1 still fixed by their long
 roots in the bed of blue clay in  which
 they originally grew4 ,if one of these 
submarine forest beds should  be        
gradually depressed and covered up by   
new deposits1 it would present  just the
 same characters as an under-clay of the

 coal1 if the  ,sigillaria and          
,lepidodendron of the ancient world were
 substituted  for the oak1 or the beech1
 of our own times4    ,in a tropical    
forest1 at the present day1 the trunks  
of fallen trees1 and  the stools of such
 trees as may have been broken by the   
violence of  storms1 remain entire for  
but a short time4 ,contrary to what     
might be  expected1 the dense wood of   
the tree decays1 and suffers from the   
ravages  of insects1 more swiftly than  
the bark4 ,and the traveller1 setting   
his  foot on a prostrate trunk1 finds   
that it is a mere shell1 which breaks   
under his weight1 and lands his foot    
amidst the insects1 or the reptiles1    
which have sought food or refuge within4
    ,the trees of the coal forests      
present parallel conditions4 ,when the  
fallen trunks which have entered into   
the composition of the bed of coal  are 
identifiable1 they are mere double      
shells of bark1 flattened together  in  
consequence of the destruction of the   

woody core2 and ,sir ,charles  ,lyell   
and ,principal ,dawson discovered1 in   
the hollow stools of coal trees  of     
,nova ,scotia1 the remains of snails1   
millipedes1 and salamander-like         
creatures1 embedded in a deposit of a   
different character from that which     
surrounded the exterior of the trees4   
,thus1 in endeavouring to comprehend    
the formation of a seam of coal1 we must
 try to picture to ourselves a  thick   
forest1 formed for the most part of     
trees like gigantic club-  mosses1      
mares'-tails1 and tree-ferns1 with here 
and there some that had  more           
resemblance to our existing yews and    
fir-trees4 ,we must suppose  that1 as   
the seasons rolled by1 the plants grew  
and developed their  spores and seeds2  
that they shed these in enormous        
quantities1 which  accumulated on the   
ground beneath2 and that1 every now and 
then1 they  added a dead frond or leaf2 
or1 at longer intervals1 a rotten       
branch1 or  a dead trunk1 to the mass4  

,a certain proportion of the spores and 
seeds no doubt fulfilled their  obvious 
function1 and1 carried by the wind to   
unoccupied regions1  extended the limits
 of the forest2 many might be washed    
away by rain into  streams1 and be lost2
 but a large portion must have remained1
 to  accumulate like beech-mast1 or     
acorns1 beneath the trees of a modern   
forest4    ,but1 in this case it may be 
asked1 why does not our ,english coal   
consist  of stems and leaves to a much  
greater extent than it does8 ,what is   
the  reason of the predominance of the  
spores and spore-cases in it8    ,a     
ready answer to this question is        
afforded by the study of a living       
full-grown club-moss4 ,shake it upon a  
piece of paper1 and it emits a  cloud of
 fine dust1 which falls over the paper1 
and is the well-known  ,lycopodium      
powder4 ,now this powder used to be1 and
 ,i believe still is1  employed for two 
objects which seem1 at first sight1 to  
have no  particular connection with one 

another4 ,it is1 or was1 employed in    
making  lightning1 and in making pills4 
,the coats of the spores contain so much
  resinous matter1 that a pinch of      
,lycopodium powder1 thrown through the  
flame of a candle1 burns with an        
instantaneous flash1 which has long done
  duty for lightning on the stage4 ,and 
the same character makes it a  capital  
coating for pills2 for the resinous     
powder prevents the drug from  being    
wetted by the saliva1 and thus bars the 
nauseous flavour from the  sensitive    
papilla2 of the tongue4    ,but this    
resinous matter1 which lies in the walls
 of the spores and  sporangia1 is a     
substance not easily altered by air and 
water1 and hence  tends to preserve     
these bodies1 just as the bituminized   
cerecloth  preserves an ,egyptian mummy2
 while1 on the other hand1 the merely   
woody  stem and leaves tend to rot1 as  
fast as the wood of the mummy's coffin  
has rotted4 ,thus the mixed heap of     
spores1 leaves1 and stems in the coal-  

forest would be persistently searched by
 the long-continued action of air  and  
rain2 the leaves and stems would        
gradually be reduced to little but      
their carbon1 or1 in other words1 to the
 condition of mineral charcoal in  which
 we find them2 while the spores and     
sporangia remained as a  comparatively  
unaltered and compact residuum4         
,there is1 indeed1 tolerably clear      
evidence that the coal must1 under some 
circumstances1 have been converted into 
a substance hard enough to be  rolled   
into pebbles1 while it yet lay at the   
surface of the earth2 for in  some seams
 of coal1 the courses of rivulets1 which
 must have been living  water1 while the
 stratum in which their remains are     
found was still at  the surface1 have   
been observed to contain rolled pebbles 
of the very  coal through which the     
stream has cut its way4    ,the         
structural facts are such as to leave no
 alternative but to adopt the  view of  
the origin of such coal as ,i have      

described1 which has just been  stated2 
but1 happily1 the process is not without
 analogy at the present  day4 ,i possess
 a specimen of what is called white coal
 from ,australia4  ,it is an inflammable
 material1 burning with a bright flame  
and having  much the consistence and    
appearance of oat-cake1 which1 ,i am    
informed  covers a considerable area4   
,it consists1 almost entirely1 of a     
compacted  mass of spores and           
spore-cases4 ,but the fine particles of 
blown sand  which are scattered through 
it1 show that it must have accumulated1 
subarially1 upon the surface of a soil  
covered by a forest of  cryptogamous    
plants1 probably tree-ferns4    ,as     
regards this important point of the     
subarial region of coal1 ,i am  glad to 
find myself in entire accordance with   
,principal ,dawson1 who bases  his      
conclusions upon other1 but no less     
forcible1 considerations4 ,in a         
passage1 which is the continuation of   
that already cited1 he writes3--    7#c7

 ,the microscopical structure and       
chemical composition of the beds of     
cannel coal and earthy bitumen1 and of  
the more highly bituminous and          
carbonaceous shale1 show them to have   
been of the nature of the fine          
vegetable mud which accumulates in the  
ponds and shallow lakes of modern       
swamps4 ,when such tine vegetable       
sediment is mixed1 as is often the case1
  with clay1 it becomes similar to the  
bituminous limestone and calcareo-      
bituminous shales of the coal-measures4 
7#d7 ,a few of the under-clays1  which  
support beds of coal1 are of the nature 
of the vegetable mud above  referred to2
 but the greater part are               
argillo-arenaceous in composition1  with
 little vegetable matter1 and bleached  
by the drainage from them of  water     
containing the products of vegetable    
decay4 ,they are1 in short1  loamy or   
clay soils1 and must have been          
sufficiently above water to admit  of   
drainage4 ,the absence of sulphurets1   

and the occurrence of carbonate  of iron
 in connection with them1 prove that1   
when they existed as soils1  rain-water1
 and not sea-water1 percolated them4    
7#e7 ,the coal and the  fossil forests  
present many evidences of subarial      
conditions4 ,most of  the erect and     
prostrate trees had become hollow shells
 of bark before  they were finally      
embedded1 and their wood had broken into
 cubical pieces  of mineral charcoal4   
,land-snails and galley-worms           
7,xylobius7 crept into  them1 and they  
became dens1 or traps1 for reptiles4    
,large quantities of  mineral charcoal  
occur on the surface of all the large   
beds of coal4 ,none  of these           
appearances could have been produced by 
subaqueous action4 7#f7  ,though the    
roots of the ,sigillaria bear more      
resemblance to the  rhizomes of certain 
aquatic plants2 yet1 structurally1 they 
are  absolutely identical with the roots
 of ,cycads1 which the stems also       
resemble4 ,further1 the ,sigillarioe    

grew on the same soils which  supported 
,conifers1 ,lepidodendra1 ,cordaites1   
and ,ferns-plants which  could not have 
grown in water4 ,again1 with the        
exception perhaps of some  ,pinnularioe1
 and ,asterophyllites1 there is a       
remarkable absence from  the coal       
measures of any form of properly aquatic
 vegetation4 7#g7 ,the  occurrence of   
marine1 or brackish-water animals1 in   
the roofs of coal-  beds1 or even in the
 coal itself1 affords no evidence of    
subaqueous  accumulation1 since the same
 thing occurs in the case of modern     
submarine  forests4 ,for these and other
 reasons1 some of which are more fully  
stated  in the papers already referred  
to1 while ,i admit that the areas of    
coal  accumulation were frequently      
submerged1 ,i must maintain that the    
true  coal is a subarial accumulation by
 vegetable growth on soils1 wet and     
swampy it is true1 but not submerged4   
,i am almost disposed to doubt whether  
it is necessary to make the  concession 

of wet and swampy2 otherwise1 there is  
nothing that ,i know  of to be said     
against this excellent conspectus of the
 reasons for  believing in the subarial 
origin of coal4    ,but the coal        
accumulated upon the area covered by one
 of the great  forests of the           
carboniferous epoch would in course of  
time1 have been  wasted away by the     
small1 but constant1 wear and tear of   
rain and streams  had the land which    
supported it remained at the same level1
 or been  gradually raised to a greater 
elevation4 ,and1 no doubt1 as much coal 
as  now exists has been destroyed1 after
 its formation1 in this way4 ,what are  
now known as coal districts owe their   
importance to the fact that they  were  
areas of slow depression1 during a      
greater or less portion of the          
carboniferous epoch2 and that1 in virtue
 of this circumstance1 ,mother  ,earth  
was enabled to cover up her vegetable   
treasures1 and preserve them  from      
destruction4    ,wherever a coal-field  

now exists1 there must formerly have    
been free  access for a great river1 or 
for a shallow sea1 bearing sediment in  
the  shape of sand and mud4 ,when the   
coal-forest area became slowly          
depressed1  the waters must have spread 
over it1 and have deposited their burden
 upon  the surface of the bed of coal1  
in the form of layers1 which are now    
converted into shale1 or sandstone4     
,then followed a period of rest1 in     
which the superincumbent shallow waters 
became completely filled up1 and        
finally replaced1 by fine mud1 which    
settled down into a new under-clay1  and
 furnished the soil for a fresh forest  
growth4 ,this flourished1 and  heaped up
 its spores and wood into coal1 until   
the stage of slow  depression           
recommenced4 ,and1 in some localities1  
as ,i have mentioned1 the  process was  
repeated until the first of the         
alternating beds had sunk to  near three
 miles below its original level at the  
surface of the earth4    ,in reflecting 

on the statement1 thus briefly made1 of 
the main facts  connected with the      
origin of the coal formed during the    
carboniferous  epoch1 two or three      
considerations suggest themselves4      
,in the first place1 the great phantom  
of geological time rises before the     
student of this1 as of all other1       
fragments of the history of our earth-- 
springing irrepressibly out of the      
facts1 like the ,djin from the jar      
which the fishermen so incautiously     
opened2 and like the ,djin again1  being
 vaporous1 shifting1 and indefinable1   
but unmistakably gigantic4  ,however    
modest the bases of one's calculation   
may be1 the minimum of time  assignable 
to the coal period remains something    
stupendous4    ,principal ,dawson is the
 last person likely to be guilty of     
exaggeration  in this matter1 and it    
will be well to consider what he has to 
say about  it3--    ,the rate of        
accumulation of coal was very slow4 ,the
 climate of the  period1 in the northern

 temperate zone1 was of such a character
 that the  true conifers show rings of  
growth1 not larger1 nor much less       
distinct1  than those of many of their  
modern congeners4 ,the ,sigillarioe and 
,calamites were not1 as often supposed1 
composed wholly1 or even  principally1  
of lax and soft tissues1 or necessarily 
short-lived4 ,the  former had1 it is    
true1 a very thick inner bark2 but their
 dense woody  axis1 their thick and     
nearly imperishable outer bark1 and     
their scanty  and rigid foliage1 would  
indicate no very rapid growth or decay4 
,in the  case of the ,sigillarioe1 the  
variations in the leaf-scars in         
different  parts of the trunk1 the      
intercalation of new ridges at the      
surface  representing that of new woody 
wedges in the axis1 the transverse marks
  left by the stages of upward growth1  
all indicate that several years must    
have been required for the growth of    
stems of moderate size4 ,the enormous   
roots of these trees1 and the condition 

of the coal-swamps1 must have  exempted 
them from the danger of being overthrown
 by violence4 ,they  probably fell in   
successive generations from natural     
decay2 and making  every allowance for  
other materials1 we may safely assert   
that every foot  of thickness of pure   
bituminous coal implies the quiet growth
 and fall of  at least fifty generations
 of ,sigillarioe1 and therefore an      
undisturbed  condition of forest growth 
enduring through many centuries4        
,further1  there is evidence that an    
immense amount of loose parenchymatous  
tissue1  and even of wood1 perished by  
decay1 and we do not know to what extent
  even the most durable tissues may have
 disappeared in this way2 so that1  in  
many coal-seams1 we may have only a very
 small part of the vegetable  matter    
produced4    ,undoubtedly the force of  
these reflections is not diminished when
 the  bituminous coal1 as in ,britain1  
consists of accumulated spores and      
spore-  cases1 rather than of stems4    

,but1 suppose we adopt ,principal       
,dawson's  assumption1 that one foot of 
coal represents fifty generations of    
coal  plants2 and1 further1 make the    
moderate supposition that each          
generation  of coal plants took ten     
years to come to maturity--then1 each   
foot-  thickness of coal represents five
 hundred years4 ,the superimposed beds  
of  coal in one coal-field may amount to
 a thickness of fifty or sixty feet1    
and therefore the coal alone1 in that   
field1 represents #ejj x #ej  #be1jjj   
years4 ,but the actual coal is but an   
insignificant portion of the total      
deposit1 which1 as has been seen1 may   
amount to between two and three  miles  
of vertical thickness4 ,suppose it be   
#ab1jjj feet--which is #bdj  times the  
thickness of the actual coal--is there  
any reason why we should  believe it may
 not have taken #bdj times as long to   
form8 ,i know of none4  ,but1 in this   
case1 the time which the coal-field     
represents would be  #be1jjj x #bdj     

#f1jjj1jjj years4 ,as affording a       
definite chronology1 of  course such    
calculations as these are of no value2  
but they have much use  in fixing one's 
attention upon a possible minimum4 ,a   
man may be puzzled  if he is asked how  
long ,rome took a-building2 but he is   
proverbially safe  if he affirms it not 
to have been built in a day2 and our    
geological  calculations are all1 at    
present1 pretty much on that footing4   
,a second consideration which the study 
of the coal brings prominently  before  
the mind of any one who is familiar with
 palaeontology is1 that the  coal       
,flora1 viewed in relation to the       
enormous period of time which it        
lasted1 and to the still vaster period  
which has elapsed since it  flourished1 
underwent little change while it        
endured1 and in its peculiar            
characters1 differs strangely little    
from that which at present exist4       
,the same species of plants are to be   
met with throughout the whole  thickness

 of a coal-field1 and the youngest are  
not sensibly different  from the oldest4
 ,but more than this4 ,notwithstanding  
that the  carboniferous period is       
separated from us by more than the whole
 time  represented by the secondary and 
tertiary formations1 the great types of 
vegetation were as distinct then as now4
 ,the structure of the modern  club-moss
 furnishes a complete explanation of the
 fossil remains of the  ,lepidodendra1  
and the fronds of some of the ancient   
ferns are hard to  distinguish from     
existing ones4 ,at the same time1 it    
must be remembered1  that there is      
nowhere in the world1 at present1 any   
forest which bears  more than a rough   
analogy with a coal-forest4 ,the types  
may remain1 but  the details of their   
form1 their relative proportions1 their 
associates1  are all altered4 ,and the  
tree-fern forest of ,tasmania1 or ,new  
,zealand1  gives one only a faint and   
remote image of the vegetation of the   
ancient  world4    ,once more1 an       

invariably-recurring lesson of          
geological history1 at  whatever point  
its study is taken up3 the lesson of the
 almost infinite  slowness of the       
modification of living forms4 ,the lines
 of the pedigrees  of living things     
break off almost before they begin to   
converge4    ,finally1 yet another      
curious consideration4 ,let us suppose  
that one of  the stupid1 salamander-like
 ,labyrinthodonts1 which pottered1 with 
much  belly and little leg1 like        
,falstaff in his old age1 among the     
coal-  forests1 could have had thinking 
power enough in his small brain to      
reflect upon the showers of spores which
 kept on falling through years  and     
centuries1 while perhaps not one in ten 
million fulfilled its  apparent purpose1
 and reproduced the organism which gave 
it birth3 surely  he might have been    
excused for moralizing upon the         
thoughtless and wanton  extravagance    
which ,nature displayed in her          
operations4    ,but we have the         

advantage over our shovel-headed        
predecessor--or possibly  ancestor--and 
can perceive that a certain vein of     
thrift runs through  this apparent      
prodigality4 ,nature is never in a      
hurry1 and seems to have  had always    
before her eyes the adage1 ,keep a thing
 long enough1 and you  will find a use  
for it4 ,she has kept her beds of coal  
many millions of  years without being   
able to find much use for them2 she has 
sent them  down beneath the sea1 and the
 sea-beasts could make nothing of them2 
she  has raised them up into dry land1  
and laid the black veins bare1 and      
still1 for ages and ages1 there was no  
living thing on the face of the  earth  
that could see any sort of value in     
them2 and it was only the other  day1 so
 to speak1 that she turned a new        
creature out of her workshop1 who  by   
degrees acquired sufficient wits to make
 a fire1 and then to discover  that the 
black rock would burn4    ,i suppose    
that nineteen hundred years ago1 when   

,julius ,caesar was good  enough to deal
 with ,britain as we have dealt with    
,new ,zealand1 the  primaeval ,briton1  
blue with cold and woad1 may have known 
that the strange  black stone1 of which 
he found lumps here and there in his    
wanderings1  would burn1 and so help to 
warm his body and cook his food4 ,saxon1
 ,dane1  and ,norman swarmed into the   
land4 ,the ,english people grew into a  
powerful  nation1 and ,nature still     
waited for a full return of the capital 
she had  invested in the ancient        
club-mosses4 ,the eighteenth century    
arrived1 and  with it ,james ,watt4 ,the
 brain of that man was the spore out of 
which was  developed the modern         
steam-engine1 and all the prodigious    
trees and  branches of modern industry  
which have grown out of this4 ,but coal 
is as  much an essential condition of   
this growth and development as carbonic 
acid is for that of a club-moss4        
,wanting coal1 we could not have smelted
  the iron needed to make our engines1  

nor have worked our engines when we  had
 got them4 ,but take away the engines1  
and the great towns of ,yorkshire  and  
,lancashire vanish like a dream4        
,manufactures give place to  agriculture
 and pasture1 and not ten men can live  
where now ten thousand  are amply       
supported4    ,thus1 all this abundant  
wealth of money and of vivid life is    
,nature's  interest upon her investment 
in club-mosses1 and the like1 so long   
ago4  ,but what becomes of the coal     
which is burnt in yielding this         
interest8  ,heat comes out of it1 light 
comes out of it2 and if we could gather 
together all that goes up the chimney1  
and all that remains in the grate  of a 
thoroughly-burnt coal-fire1 we should   
find ourselves in possession  of a      
quantity of carbonic acid1 water1       
ammonia1 and mineral matters1  exactly  
equal in weight to the coal4 ,but these 
are the very matters with  which ,nature
 supplied the club-mosses which made the
 coal ,she is paid  back principal and  

interest at the same time2 and she      
straightway invests  the carbonic acid1 
the water1 and the ammonia in new forms 
of life1  feeding with them the plants  
that now live4 ,thrifty ,nature6 ,surely
 no  prodigal1 but most notable of      
housekeepers6        ,,vi      ,,on     
,,the ,,border ,,territory ,,between    
,,the ,,animal ,,and ,,the ,,vegetable  
,,kingdoms    #ahgf    ,in the whole    
history of science there is nothing more
 remarkable than the  rapidity of the   
growth of biological knowledge within   
the last half-  century1 and the extent 
of the modification which has thereby   
been  effected in some of the           
fundamental conceptions of the          
naturalist4    ,in the second edition of
 the ,rgne ,animal1 published in #ahbh1 
,cuvier  devotes a special section to   
the ,division of ,organised ,beings into
  ,animals and ,vegetables1 in which the
 question is treated with that          
comprehensiveness of knowledge and clear
 critical judgment which  characterise  

his writings1 and justify us in         
regarding them as  representative       
expressions of the most extensive1 if   
not the profoundest1  knowledge of his  
time4 ,he tells us that living beings   
have been  subdivided from the earliest 
times into animated beings1 which       
possess  sense and motion1 and          
inanimated beings1 which are devoid of  
these  functions and simply vegetate4   
,although the roots of plants direct    
themselves towards moisture1 and  their 
leaves towards air and light1--although 
the parts of some plants  exhibit       
oscillating movements without any       
perceptible cause1 and the  leaves of   
others retract when touched1--yet none  
of these movements  justify the         
ascription to plants of perception or of
 will4 ,from the  mobility of animals1  
,cuvier1 with his characteristic        
partiality for  teleological reasoning1 
deduces the necessity of the existence  
in them of  an alimentary cavity1 or    
reservoir of food1 whence their         

nutrition may be  drawn by the vessels1 
which are a sort of internal roots2 and1
 in the  presence of this alimentary    
cavity1 he naturally sees the primary   
and the  most important distinction     
between animals and plants4             
,following out his teleological         
argument1 ,cuvier remarks that the      
organisation of this cavity and its     
appurtenances must needs vary  according
 to the nature of the aliment1 and the  
operations which it has  to undergo1    
before it can be converted into         
substances fitted for  absorption2 while
 the atmosphere and the earth supply    
plants with juices  ready prepared1 and 
which can be absorbed immediately4 ,as  
the animal body  required to be         
independent of heat and of the          
atmosphere1 there were no  means by     
which the motion of its fluids could be 
produced by internal  causes4 ,hence    
arose the second great distinctive      
character of animals1 or  the           
circulatory system1 which is less       

important than the digestive1 since  it 
was unnecessary1 and therefore is       
absent1 in the more simple animals4     
,animals further needed muscles for     
locomotion and nerves for sensibility4  
,hence1 says ,cuvier1 it was necessary  
that the chemical composition of the    
animal body should be more complicated  
than that of the plant2 and it is  so1  
inasmuch as an additional substance1    
nitrogen1 enters into it as an          
essential element2 while1 in plants1    
nitrogen is only accidentally joined    
with he three other fundamental         
constituents of organic beings--carbon1 
hydrogen1 and oxygen4 ,indeed1 he       
afterwards affirms that nitrogen is     
peculiar to animals2 and herein he      
places the third distinction between    
the animal and the plant4 ,the soil and 
the atmosphere supply plants with       
water1 composed of hydrogen and oxygen2 
air1 consisting of nitrogen and  oxygen2
 and carbonic acid1 containing carbon   
and oxygen4 ,they retain the  hydrogen  

and the carbon1 exhale the superfluous  
oxygen1 and absorb little  or no        
nitrogen4 ,the essential character of   
vegetable life is the  exhalation of    
oxygen1 which is effected through the   
agency of light4  ,animals1 on the      
contrary1 derive their nourishment      
either directly or  indirectly from     
plants4 ,they get rid of the superfluous
 hydrogen and  carbon1 and accumulate   
nitrogen4 ,the relations of plants and  
animals to  the atmosphere are therefore
 inverse4 ,the plant withdraws water and
  carbonic acid from the atmosphere1 the
 animal contributes both to it4         
,respiration--that is1 the absorption of
 oxygen and the exhalation of  carbonic 
acid--is the specially animal function  
of animals1 and  constitutes their      
fourth distinctive character4    ,thus  
wrote ,cuvier in #ahbh4 ,but1 in the    
fourth and fifth decades of this        
century1 the greatest and most rapid    
revolution which biological science  has
 ever undergone was effected by the     

application of the modern  microscope to
 the investigation of organic structure2
 by the introduction  of exact and      
easily manageable methods of conducting 
the chemical  analysis of organic       
compounds2 and finally1 by the          
employment of  instruments of precision 
for the measurement of the physical     
forces which  are at work in the living 
economy4    ,that the semi-fluid        
contents 7which we now term protoplasm7 
of the cells  of certain plants1 such as
 the ,charoe are in constant and regular
  motion1 was made out by ,bonaventura  
,corti a century ago2 but the fact1     
important as it was1 fell into oblivion1
 and had to be rediscovered by          
,treviranus in #ahjg4 ,robert ,brown    
noted the more complex motions of the   
protoplasm in the cells of ,tradescantia
 in #ahca2 and now such movements  of   
the living substance of plants are well 
known to be some of the most            
widely-prevalent phenomena of vegetable 
life4    ,agardh1 and other of the      

botanists of ,cuvier's generation1 who  
occupied  themselves with the lower     
plants1 had observed that1 under        
particular  circumstances1 the contents 
of the cells of certain water-weeds were
 set  free1 and moved about with        
considerable velocity1 and with all the 
appearances of spontaneity1 as          
locomotive bodies1 which1 from their    
similarity to animals of simple         
organisation1 were called zoospores4    
,even as late as #ahde1 however1 a      
botanist of ,schleiden's eminence dealt 
very sceptically with these statements2 
and his scepticism was the more         
justified1 since ,ehrenberg1 in his     
elaborate and comprehensive work on  the
 ,infusoria1 had declared the greater   
number of what are now  recognised as   
locomotive plants to be animals4    ,at 
the present day1 innumerable plants and 
free plant cells are known to  pass the 
whole or part of their lives in an      
actively locomotive  condition1 in no   
wise distinguishable from that of one of

 the simpler  animals2 and1 while in    
this condition1 their movements are1 to 
all  appearance1 as spontaneous--as much
 the product of volition--as those of   
such animals4    ,hence the teleological
 argument for ,cuvier's first diagnostic
 character--  the presence in animals of
 an alimentary cavity1 or internal      
pocket1 in  which they can carry about  
their nutriment--has broken down1 so    
far1 at  least1 as his mode of stating  
it goes4 ,and1 with the advance of      
microscopic anatomy1 the universality of
 the fact itself among animals  has     
ceased to be predicable4 ,many animals  
of even complex structure1  which live  
parasitically within others1 are wholly 
devoid of an  alimentary cavity4 ,their 
food is provided for them1 not only     
ready  cooked1 but ready digested1 and  
the alimentary canal1 become            
superfluous1  has disappeared4 ,again1  
the males of most ,rotifers have no     
digestive  apparatus2 as a ,german      
naturalist has remarked1 they devote    

themselves  entirely to the             
,minnedienst1 and are to be reckoned    
among the few  realisations of the      
,byronic ideal of a lover4 ,finally1    
amidst the lowest  forms of animal life1
 the speck of gelatinous protoplasm1    
which  constitutes the whole body1 has  
no permanent digestive cavity or mouth1 
but takes in its food anywhere2 and     
digests1 so to speak1 all over its      
body4 ,but although ,cuvier's leading   
diagnosis of the animal from the  plant 
will not stand a strict test1 it remains
 one of the most constant  of the       
distinctive characters of animals4 ,and1
 if we substitute for the  possession of
 an alimentary cavity1 the power of     
taking solid nutriment  into the body   
and there digesting it1 the definition  
so changed will  cover all animals      
except certain parasites1 and the few   
and exceptional  cases of non-parasitic 
animals which do not feed at all4 ,on   
the other  hand1 the definition thus    
amended will exclude all ordinary       

vegetable  organisms4    ,cuvier himself
 practically gives up his second        
distinctive mark when he  admits that it
 is wanting in the simpler animals4     
,the third distinction is based on a    
completely erroneous conception of  the 
chemical differences and resemblances   
between the constituents of  animal and 
vegetable organisms1 for which ,cuvier  
is not responsible1 as  it was current  
among contemporary chemists4 ,it is now 
established that  nitrogen is as        
essential a constituent of vegetable as 
of animal living  matter2 and that the  
latter is1 chemically speaking1 just as 
complicated  as the former4 ,starchy    
substances1 cellulose and sugar1 once   
supposed to  be exclusively confined to 
plants1 are now known to be regular and 
normal  products of animals4 ,amylaceous
 and saccharine substances are largely  
manufactured1 even by the highest       
animals2 cellulose is widespread as a   
constituent of the skeletons of the     
lower animals2 and it is probable  that 

amyloid substances are universally      
present in the animal organism1  though 
not in the precise form of starch4      
,moreover1 although it remains true that
 there is an inverse relation  between  
the green plant in sunshine and the     
animal1 in so far as1 under  these      
circumstances1 the green plant          
decomposes carbonic acid and exhales    
oxygen1 while the animal absorbs oxygen 
and exhales carbonic acid2 yet1  the    
exact researches of the modern chemical 
investigators of the  physiological     
processes of plants have clearly        
demonstrated the fallacy  of attempting 
to draw any general distinction between 
animals and  vegetables on this ground4 
,in fact1 the difference vanishes with  
the  sunshine1 even in the case of the  
green plant2 which1 in the dark1        
absorbs oxygen and gives out carbonic   
acid like any animal4#a ,on the  other  
hand1 those plants1 such as the fungi1  
which contain no chlorophyll  and are   
not green1 are always1 so far as        

respiration is concerned1 in the  exact 
position of animals4 ,they absorb oxygen
 and give out carbonic acid4            
,footnote #a3 ,there is every reason to 
believe that living plants1 like  living
 animals1 always respire1 and1 in       
respiring1 absorb oxygen and give  off  
carbonic acid2 but1 that in green plants
 exposed to daylight or to  the electric
 light1 the quantity of oxygen evolved  
in consequence of the  decomposition of 
carbonic acid by a special apparatus    
which green plants  possess exceeds that
 absorbed in the concurrent respiratory 
process4    ,thus1 by the progress of   
knowledge1 ,cuvier's fourth distinction 
between  the animal and the plant has   
been as completely invalidated as the   
third  and second2 and even the first   
can be retained only in a modified form 
and subject to exceptions4    ,but has  
the advance of biology simply tended to 
break down old  distinctions1 without   
establishing new ones8    ,with a       
qualification1 to be considered         

presently1 the answer to this  question 
is undoubtedly in the affirmative4 ,the 
famous researches of  ,schwann and      
,schleiden in #ahcg and the following   
years1 founded the modern  science of   
histology1 or that branch of anatomy    
which deals with the  ultimate visible  
structure of organisms1 as revealed by  
the microscope2  and1 from that day to  
this1 the rapid improvement of methods  
of  investigation1 and the energy of a  
host of accurate observers1 have given  
greater and greater breadth and firmness
 to ,schwann's great  generalisation1   
that a fundamental unity of structure   
obtains in animals  and plants2 and     
that1 however diverse may be the        
fabrics1 or tissues1  of which their    
bodies are composed1 all these varied   
structures result  from the             
metamorphosis of morphological units    
7termed cells1 in a more  general sense 
than that in which the word cells was at
 first employed71  which are not only   
similar in animals and in plants        

respectively1 but  present a close      
resemblance1 when those of animals and  
those of plants  are compared together4 
,the contractility which is the         
fundamental condition of locomotion1 has
  not only been discovered to exist far 
more widely among plants than was       
formerly imagined2 but1 in plants1 the  
act of contraction has been found  to be
 accompanied1 as ,dr4 ,burdon           
,sanderson's interesting investigations 
have shown1 by a disturbance of the     
electrical state of the contractile     
substance1 comparable to that which was 
found by ,du ,bois ,reymond to be a     
concomitant of the activity of ordinary 
muscle in animals4    ,again1 ,i know of
 no test by which the reaction of the   
leaves of the  ,sundew and of other     
plants to stimuli1 so fully and         
carefully studied by  ,mr4 ,darwin1 can 
be distinguished from those acts of     
contraction following  upon stimuli1    
which are called reflex in animals4     
,on each lobe of the bilobed leaf of    

,venus's fly-trap 7,dionoea  muscipula7 
are three delicate filaments which stand
 out at right angle  from the surface of
 the leaf4 ,touch one of them with the  
end of a fine  human hair and the lobes 
of the leaf instantly close together#b  
in  virtue of an act of contraction of  
part of their substance1 just as the    
body of a snail contracts into its shell
 when one of its horns is  irritated4   
,footnote #b3 ,darwin1 ,insectivorous   
,plants1 p4 #bhi4    ,the reflex action 
of the snail is the result of the       
presence of a nervous  system in the    
animal4 ,a molecular change takes place 
in the nerve of the  tentacle1 is       
propagated to the muscles by which the  
body is retracted1  and causing them to 
contract1 the act of retraction is      
brought about4 ,of  course the          
similarity of the acts does not         
necessarily involve the  conclusion that
 the mechanism by which they are        
effected is the same2 but  it suggests a
 suspicion of their identity which needs

 careful testing4    ,the results of    
recent inquiries into the structure of  
the nervous system  of animals converge 
towards the conclusion that the nerve   
fibres1 which  we have hitherto regarded
 as ultimate elements of nervous tissue1
 are not  such1 but are simply the      
visible aggregations of vastly more     
attenuated  filaments1 the diameter of  
which dwindles down to the limits of our
  present microscopic vision1 greatly as
 these have been extended by modern     
improvements of the microscope2 and that
 a nerve is1 in its essence1  nothing   
but a linear tract of specially modified
 protoplasm between two  points of an   
organism--one of which is able to affect
 the other by means  of the             
communication so established4 ,hence1 it
 is conceivable that even  the simplest 
living being may possess a nervous      
system4 ,and the question  whether      
plants are provided with a nervous      
system or not1 thus acquires a  new     
aspect1 and presents the histologist and

 physiologist with a problem  of extreme
 difficulty1 which must be attacked from
 a new point of view  and by the aid of 
methods which have yet to be invented4  
,thus it must be admitted that plants   
may be contractile and locomotive2      
that1 while locomotive1 their movements 
may have as much appearance of          
spontaneity as those of the lowest      
animals2 and that many exhibit  actions1
 comparable to those which are brought  
about by the agency of a  nervous system
 in animals4 ,and it must be allowed to 
be possible that  further research may  
reveal the existence of something       
comparable to a  nervous system in      
plants4 ,so that ,i know not where we   
can hope to find  any absolute          
distinction between animals and plants1 
unless we return to  their mode of      
nutrition1 and inquire whether certain  
differences of a  more occult character 
than those imagined to exist by ,cuvier1
 and which  certainly hold good for the 
vast majority of animals and plants1 are

 of  universal application4    ,a bean  
may be supplied with water in which     
salts of ammonia and certain  other     
mineral salts are dissolved in due      
proportion2 with atmospheric air        
containing its ordinary minute dose of  
carbonic acid2 and with nothing  else   
but sunlight and heat4 ,under these     
circumstances1 unnatural as they  are1  
with proper management1 the bean will   
thrust forth its radicle and  its       
plumule2 the former will grow down into 
roots1 the latter grow up  into the stem
 and leaves of a vigorous bean-plant2   
and this plant will1  in due time1      
flower and produce its crop of beans1   
just as if it were  grown in the garden 
or in the field4    ,the weight of the  
nitrogenous protein compounds1 of the   
oily1 starchy1  saccharine and woody    
substances contained in the full-grown  
plant and its  seeds1 will be vastly    
greater than the weight of the same     
substances  contained in the bean from  
which it sprang4 ,but nothing has been  

supplied  to the bean save water1       
carbonic acid1 ammonia1 potash1 lime1   
iron1 and  the like1 in combination with
 phosphoric1 sulphuric1 and other acids4
  ,neither protein1 nor fat1 nor starch1
 nor sugar1 nor any substance in the    
slightest degree resembling them1 has   
formed part of the food of the  bean4   
,but the weights of the carbon1         
hydrogen1 oxygen1 nitrogen1  phosphorus1
 sulphur1 and other elementary bodies   
contained in the bean-  plant1 and in   
the seeds which it produces1 are exactly
 equivalent to the  weights of the same 
elements which have disappeared from the
 materials  supplied to the bean during 
its growth4 ,whence it follows that the 
bean  has taken in only the raw         
materials of its fabric1 and has        
manufactured  them into bean-stuffs4    
,the bean has been able to perform this 
great chemical feat by the help of  its 
green colouring matter1 or chlorophyll2 
for it is only the green  parts of the  
plant which1 under the influence of     

sunlight1 have the  marvellous power of 
decomposing carbonic acid1 setting free 
the oxygen  and laying hold of the      
carbon which it contains4 ,in fact1 the 
bean  obtains two of the absolutely     
indispensable elements of its substance 
from two distinct sources2 the watery   
solution1 in which its roots are        
plunged1 contains nitrogen but no       
carbon2 the air1 to which the leaves    
are exposed1 contains carbon1 but its   
nitrogen is in the state of a free  gas1
 in which condition the bean can make no
 use of it2#c and the  chlorophyll#d is 
the apparatus by which the carbon is    
extracted from the  atmospheric carbonic
 acid--the leaves being the chief       
laboratories in  which this operation is
 effected4    ,footnote #c3 ,i purposely
 assume that the air with which the bean
 is  supplied in the case stated        
contains no ammoniacal salts4           
,footnote #d3 ,the recent researches of 
,pringsheim have raised a host of       
questions as to the exact share taken by

 chlorophyll in the chemical  operations
 which are effected by the green parts  
of plants4 ,it may be  that the         
chlorophyll is only a constant          
concomitant of the actual  deoxidising  
apparatus4    ,the great majority of    
conspicuous plants are1 as everybody    
knows1 green2  and this arises from the 
abundance of their chlorophyll4 ,the few
 which  contain no chlorophyll and are  
colourless1 are unable to extract the   
carbon which they require from          
atmospheric carbonic acid1 and lead a   
parasitic existence upon other plants2  
but it by no means follows1 often  as   
the statement has been repeated1 that   
the manufacturing power of  plants      
depends on their chlorophyll1 and its   
interaction with the rays of  the sun4  
,on the contrary1 it is easily          
demonstrated1 as ,pasteur first  proved1
 that the lowest fungi1 devoid of       
chlorophyll1 or of any  substitute for  
it1 as they are1 nevertheless possess   
the characteristic  manufacturing powers

 of plants in a very high degree4 ,only 
it is  necessary that they should be    
supplied with a different kind of raw   
material2 as they cannot extract carbon 
from carbonic acid1 they must be        
furnished with something else that      
contains carbon4 ,tartaric acid is such 
a substance2 and if a single spore of   
the commonest and most troublesome  of  
moulds--,penicillium--be sown in a      
saucerful of water1 in which  tartrate  
of ammonia1 with a small percentage of  
phosphates and sulphates  is contained1 
and kept warm1 whether in the dark or   
exposed to light1 it  will1 in a short  
time1 give rise to a thick crust of     
mould1 which  contains many million     
times the weight of the original spore1 
in protein  compounds and cellulose4    
,thus we have a very wide basis of fact 
for the  generalisation that plants are 
essentially characterised by their      
manufacturing capacity--by their power  
of working up mere mineral matters  into
 complex organic compounds4             

,contrariwise1 there is a no less wide  
foundation for the generalisation  that 
animals1 as ,cuvier puts it1 depend     
directly or indirectly upon  plants for 
the materials of their bodies2 that is1 
either they are  herbivorous1 or they   
eat other animals which are herbivorous4
    ,but for what constituents of their 
bodies are animals thus dependent upon  
plants8 ,certainly not for their horny  
matter2 nor for chondrin1 the  proximate
 chemical element of cartilage2 nor for 
gelatine2 nor for  syntonin1 the        
constituent of muscle2 nor for their    
nervous or biliary  substances2 nor for 
their amyloid matters2 nor1 necessarily1
 for their  fats4    ,it can be         
experimentally demonstrated that animals
 can make these for  themselves4 ,but   
that which they cannot make1 but must1  
in all known  cases1 obtain directly or 
indirectly from plants1 is the peculiar 
nitrogenous matter1 protein4 ,thus the  
plant is the ideal proltaire of  the    
living world1 the worker who produces2  

the animal1 the ideal  aristocrat1 who  
mostly occupies himself in consuming1   
after the manner of  that noble         
representative of the line of ,zhdarm1  
whose epitaph is  written in ,sartor    
,resartus4    ,here is our last hope of 
finding a sharp line of demarcation     
between  plants and animals2 for1 as ,i 
have already hinted1 there is a border  
territory between the two kingdoms1 a   
sort of no-man's-land1 the  inhabitants 
of which certainly cannot be            
discriminated and brought to  their     
proper allegiance in any other way4     
,some months ago1 ,professor ,tyndall   
asked me to examine a drop of infusion  
of hay1 placed under an excellent and   
powerful microscope1 and to tell  him   
what ,i thought some organisms visible  
in it were4 ,i looked and  observed1 in 
the first place1 multitudes of ,bacteria
 moving about with  their ordinary      
intermittent spasmodic wriggles4 ,as to 
the vegetable  nature of these there is 
now no doubt4 ,not only does the close  

resemblance of the ,bacteria to         
unquestionable plants1 such as the      
,oscillatorioe and the lower forms of   
,fungi1 justify this conclusion1  but   
the manufacturing test settles the      
question at once4 ,it is only  needful  
to add a minute drop of fluid containing
 ,bacteria1 to water in  which tartrate1
 phosphate1 and sulphate of ammonia are 
dissolved2 and1 in  a very short space  
of time1 the clear fluid becomes milky  
by reason of  their prodigious          
multiplication1 which1 of course1       
implies the  manufacture of living      
,bacterium-stuff out of these merely    
saline matters4    ,but other active    
organisms1 very much larger than the    
,bacteria1  attaining in fact the       
comparatively gigantic dimensions of    
#a_/cjjj of an  inch or more1           
incessantly crossed the field of view4  
,each of these had a  body shaped like a
 pear1 the small end being slightly     
incurved and  produced into a long      
curved filament1 or cilium1 of extreme  

tenuity4  ,behind this1 from the concave
 side of the incurvation1 proceeded     
another  long cilium1 so delicate as to 
be discernible only by the use of the   
highest powers and careful management of
 the light4 ,in the centre of the       
pear-shaped body a clear round space    
could occasionally be discerned1 but    
not always2 and careful watching showed 
that this clear vacuity appeared        
gradually1 and then shut up and         
disappeared suddenly1 at regular        
intervals4 ,such a structure is of      
common occurrence among the lowest      
plants and animals1 and is known as a   
contractile vacuole4    ,the little     
creature thus described sometimes       
propelled itself with great  activity1  
with a curious rolling motion1 by the   
lashing of the front  cilium1 while the 
second cilium trailed behind2 sometimes 
it anchored  itself by the hinder cilium
 and was spun round by the working of   
the  other1 its motions resembling those
 of an anchor buoy in a heavy sea4      

,sometimes1 when two were in full career
 towards one another1 each would  appear
 dexterously to get out of the other's  
way2 sometimes a crowd would  assemble  
and jostle one another1 with as much    
semblance of individual  effort as a    
spectator on the ,grands ,mulets might  
observe with a telescope  among the     
specks representing men in the valley of
 ,chamounix4    ,the spectacle1 though  
always surprising1 was not new to me4   
,so my reply  to the question put to me 
was1 that these organisms were what     
biologists  call ,monads1 and though    
they might be animals1 it was also      
possible  that they might1 like the     
,bacteria1 be plants4 ,my friend        
received my  verdict with an expression 
which showed a sad want of respect for  
authority4 ,he would as soon believe    
that a sheep was a plant4 ,naturally    
piqued by this want of faith1 ,i have   
thought a good deal over the matter2    
and1 as ,i still rest in the lame       
conclusion ,i originally expressed1 and 

must even now confess that ,i cannot    
certainly say whether this creature  is 
an animal or a plant1 ,i think it may be
 well to state the grounds of  my       
hesitation at length4 ,but1 in the first
 place1 in order that ,i may            
conveniently distinguish this ,monad    
from the multitude of other things      
which go by the same designation1 ,i    
must give it a name of its own4 ,i      
think 7though1 for reasons which need   
not be stated at present1 ,i am not     
quite sure7 that it is identical with   
the species ,monas lens as defined  by  
the eminent ,french microscopist        
,dujardin1 though his magnifying power  
was probably insufficient to enable him 
to see that it is curiously like  a much
 larger form of monad which he has named
 ,heteromita4 ,i shall1  therefore1 call
 it not ,monas1 but ,heteromita lens4   
,i have been unable to devote to my     
,heteromita the prolonged study  needful
 to work out its whole history1 which   
would involve weeks1 or it  may be      

months1 of unremitting attention4 ,but  
,i the less regret this  circumstance1  
as some remarkable observations recently
 published by  ,messrs4 ,dallinger and  
,drysdale#e on certain ,monads1 relate1 
in part1 to  a form so similar to my    
,heteromita lens1 that the history of   
the one  may be used to illustrate that 
of the other4 ,these most patient and   
painstaking observers1 who employed the 
highest attainable powers of the        
microscope and1 relieving one another1  
kept watch day and night over the  same 
individual monads1 have been enabled to 
trace out the whole history  of their   
,heteromita2 which they found in        
infusions of the heads of  fishes of the
 ,cod tribe4    ,footnote #e3           
,researches in the ,life-history of a   
,cercomonad3 a ,lesson in  ,biogenesis2 
and ,further ,researches in the         
,life-history of the ,monads1           
--,monthly ,microscopical ,journal1     
#ahgc4    ,of the four monads described 
and figured by these investigators1 one1

 as  ,i have said1 very closely         
resembles ,heteromita lens in every     
particular1 except that it has a        
separately distinguishable central      
particle or nucleus1 which is not       
certainly to be made out in  ,heteromita
 lens2 and that nothing is said by      
,messrs4 ,dallinger and  ,drysdale of   
the existence of a contractile vacuole  
in this monad1 though  they describe it 
in another4    ,their ,heteromita1      
however1 multiplied rapidly by fission4 
,sometimes a  transverse constriction   
appeared2 the hinder half developed a   
new cilium1  and the hinder cilium      
gradually split from its base to its    
free end1  until it was divided into    
two2 a process which1 considering the   
fact that  this fine filament cannot be 
much more than #a_/ajjjjj of an inch in 
diameter1 is wonderful enough4 ,the     
constriction of the body extended       
inwards until the two portions were     
united by a narrow isthmus2 finally1    
they separated and each swam away by    

itself1 a complete ,heteromita1         
provided with its two cilia4 ,sometimes 
the constriction took a  longitudinal   
direction1 with the same ultimate       
result4 ,in each case the  process      
occupied not more than six or seven     
minutes4 ,at this rate1 a  single       
,heteromita would give rise to a        
thousand like itself in the  course of  
an hour1 to about a million in two      
hours1 and to a number  greater than the
 generally assumed number of human      
beings now living in  the world in three
 hours2 or1 if we give each ,heteromita 
an hour's  enjoyment of individual      
existence1 the same result will be      
obtained in  about a day4 ,the apparent 
suddenness of the appearance of         
multitudes of  such organisms as these  
in any nutritive fluid to which one     
obtains  access is thus easily          
explained4    ,during these processes of
 multiplication by fission1 the         
,heteromita  remains active2 but        
sometimes another mode of fission       

occurs4 ,the body  becomes rounded and  
quiescent1 or nearly so2 and1 while in  
this resting  state1 divides into two   
portions1 each of which is rapidly      
converted into  an active ,heteromita4  
,a still more remarkable phenomenon is  
that kind of multiplication which  is   
preceded by the union of two monads1 by 
a process which is termed  conjugation4 
,two active ,heteromitoe become applied 
to one another1  and then slowly and    
gradually coalesce into one body4 ,the  
two nuclei run  into one2 and the mass  
resulting from the conjugation of the   
two  ,heteromitoe1 thus fused together1 
has a triangular form4 ,the two pairs   
of cilia are to be seen1 for some time1 
at two of the angles1 which  answer to  
the small ends of the conjoined monads2 
but they ultimately  vanish1 and the    
twin organism1 in which all visible     
traces of  organisation have            
disappeared1 falls into a state of rest4
 ,sudden wave-  like movements of its   
substance next occur2 and1 in a short   

time1 the  apices of the triangular mass
 burst1 and give exit to a dense        
yellowish1  glairy fluid1 filled with   
minute granules4 ,this process1 which1  
it will  be observed1 involves the      
actual confluence and mixture of the    
substance  of two distinct organisms1 is
 effected in the space of about two     
hours4    ,the authors whom ,i quote say
 that they cannot express the excessive 
minuteness of the granules in question1 
and they estimate their diameter  at    
less than #a_/bjjjjj of an inch4 ,under 
the highest powers of the  microscope1  
at present applicable1 such specks are  
hardly discernible4  ,nevertheless1     
particles of this size are massive when 
compared to  physical molecules2 whence 
there is no reason to doubt that each1  
small  as it is1 may have a molecular   
structure sufficiently complex to give  
rise to the phenomena of life4 ,and1 as 
a matter of fact1 by patient  watching  
of the place at which these             
infinitesimal living particles were     

discharged1 our observers assured       
themselves of their growth and          
development into new monads4 ,in about  
four hours from their being set  free1  
they had attained a sixth of the length 
of the parent1 with the  characteristic 
cilia1 though at first they were quite  
motionless2 and1 in  four hours more1   
they had attained the dimensions and    
exhibited all the  activity of the      
adult4 ,these inconceivably minute      
particles are therefore  the germs of   
the ,heteromita2 and from the dimensions
 of these germs it  is easily shown that
 the body formed by conjugation may1 at 
a low  estimate1 have given exit to     
thirty thousand of them2 a result of a  
matrimonial process whereby the         
contracting parties1 without a metaphor1
  become one flesh1 enough to make a    
,malthusian despair of the future of    
the ,universe4    ,i am not aware that  
the investigators from whom ,i have     
borrowed this  history have endeavoured 
to ascertain whether their monads take  

solid  nutriment or not2 so that though 
they help us very much to fill up the   
blanks in the history of my ,heteromita1
 their observations throw no  light on  
the problem we are trying to solve--,is 
it an animal or is it a  plant8         
,undoubtedly it is possible to bring    
forward very strong arguments in  favour
 of regarding ,heteromita as a plant4   
,for example1 there is a ,fungus1 an    
obscure and almost microscopic mould1   
termed ,peronospora infestans4 ,like    
many other ,fungi1 the ,peronosporoe    
are parasitic upon other plants2 and    
this particular ,peronospora  happens to
 have attained much notoriety and       
political importance1 in a  way not     
without a parallel in the career of     
notorious politicians1  namely1 by      
reason of the frightful mischief it has 
done to mankind4 ,for  it is this       
,fungus which is the cause of the potato
 disease2 and1  therefore1 ,peronospora 
infestans 7doubtless of exclusively     
,saxon  origin1 though not accurately   

known to be so7 brought about the ,irish
  famine4 ,the plants afflicted with the
 malady are found to be infested by  a  
mould1 consisting of fine tubular       
filaments1 termed hyphoe1 which  burrow 
through the substance of the potato     
plant1 and appropriate to  themselves   
the substance of their host2 while1 at  
the same time1 directly  or indirectly1 
they set up chemical changes by which   
even its woody  framework becomes       
blackened1 sodden1 and withered4    ,in 
structure1 however1 the ,peronospora is 
as much a mould as the common           
,penicillium2 and just as the           
,penicillium multiplies by the breaking 
up of its hyphoe into separate rounded  
bodies1 the spores2 so1 in the          
,peronospora1 certain of the hyphoe grow
 out into the air through the           
interstices of the superficial cells of 
the potato plant1 and develop  spores4  
,each of these hyphoe usually gives off 
several branches4 ,the ends  of the     
branches dilate and become closed sacs1 

which eventually drop off  as spores4   
,the spores falling on some part of the 
same potato plant1 or  carried by the   
wind to another1 may at once germinate1 
throwing out  tubular prolongations     
which become hyphoe1 and burrow into the
 substance  of the plant attacked4 ,but1
 more commonly1 the contents of the     
spore  divide into six or eight separate
 portions4 ,the coat of the spore gives 
way1 and each portion then emerges as an
 independent organism1 which has  the   
shape of a bean1 rather narrower at one 
end than the other1 convex on  one side1
 and depressed or concave on the        
opposite4 ,from the depression1  two    
long and delicate cilia proceed1 one    
shorter than the other1 and  directed   
forwards4 ,close to the origin of these 
cilia1 in the substance  of the body1 is
 a regularly pulsating1 contractile     
vacuole4 ,the shorter  cilium vibrates  
actively1 and effects the locomotion of 
the organism1  while the other trails   
behind2 the whole body rolling on its   

axis with  its pointed end forwards4    
,the eminent botanist1 ,de ,bary1 who   
was not thinking of our problem1 tells  
us1 in describing the movements of these
 ,zoospores1 that1 as they swim  about1 
,foreign bodies are carefully avoided1  
and the whole movement has  a deceptive 
likeness to the voluntary changes of    
place which are observed  in microscopic
 animals4    ,after swarming about in   
this way in the moisture on the surface 
of a leaf  or stem 7which1 film though  
it may be1 is an ocean to such a fish7  
for  half an hour1 more or less1 the    
movement of the zoospore becomes slower1
  and is limited to a slow turning upon 
its axis1 without change of place4  ,it 
then becomes quite quiet1 the cilia     
disappear1 it assumes a spherical  form1
 and surrounds itself with a distinct1  
though delicate1 membranous  coat4 ,a   
protuberance then grows out from one    
side of the sphere1 and  rapidly        
increasing in length1 assumes the       
character of a hypha4 ,the  latter      

penetrates into the substance of the    
potato plant1 either by  entering a     
stomate1 or by boring through the wall  
of an epidermic cell1  and ramifies1 as 
a mycelium1 in the substance of the     
plant1 destroying  the tissues with     
which it comes in contact4 ,as these    
processes of  multiplication take place 
very rapidly1 millions of spores are    
soon set  free from a single infested   
plant2 and1 from their minuteness1 they 
are  readily transported by the gentlest
 breeze4 ,since1 again1 the zoospores   
set free from each spore1 in virtue of  
their powers of locomotion1  swiftly    
disperse themselves over the surface1 it
 is no wonder that the  infection1 once 
started1 soon spreads from field to     
field1 and extends  its ravages over a  
whole country4    ,however1 it does not 
enter into my present plan to treat of  
the potato  disease1 instructively as   
its history bears upon that of other    
epidemics2  and ,i have selected the    
case of the ,peroganspora simply because

 it  affords an example of an organism1 
which1 in one stage of its existence1   
is truly a ,monad1 indistinguishable by 
any important character from our        
,heteromita1 and extraordinarily like it
 in some respects4 ,and yet this  ,monad
 can be traced1 step by step1 through   
the series of metamorphoses  which ,i   
have described1 until it assumes the    
features of an organism1  which is as   
much a plant as is an oak or an elm4    
,moreover1 it would be possible to      
pursue the analogy farther4 ,under      
certain circumstances1 a process of     
conjugation takes place in the          
,peronospora4 ,two separate portions of 
its protoplasm become fused  together1  
surround themselves with a thick coat   
and give rise to a sort  of vegetable   
egg called an oospore4 ,after a period  
of rest1 the  contents of the oospore   
break up into a number of zoospores like
 those  already described1 each of      
which1 after a period of activity1      
germinates  in the ordinary way4 ,this  

process obviously corresponds with the  
conjugation and subsequent setting free 
of germs in the ,heteromita4    ,but it 
may be said that the ,peronospora is1   
after all1 a questionable  sort of      
plant2 that it seems to be wanting in   
the manufacturing power1  selected as   
the main distinctive character of       
vegetable life2 or1 at any  rate1 that  
there is no proof that it does not get  
its protein matter  ready made from the 
potato plant4    ,let us1 therefore1    
take a case which is not open to these  
objections4    ,there are some small    
plants known to botanists as members of 
the genus  ,colcochaete1 which1 without 
being truly parasitic1 grow upon certain
  water-weeds1 as lichens grow upon     
trees4 ,the little plant has the form of
  an elegant green star1 the branching  
arms of which are divided into  cells4  
,its greenness is due to its            
chlorophyll1 and it undoubtedly has  the
 manufacturing power in full degree1    
decomposing carbonic acid and  setting  

oxygen free1 under the influence of     
sunlight4 ,but the  protoplasmic        
contents of some of the cells of which  
the plant is made up  occasionally      
divide1 by a method similar to that     
which effects the  division of the      
contents of the ,peronospora spore2 and 
the severed  portions are then set free 
as active monad-like zoospores4 ,each is
 oval  and is provided at one extremity 
with two long active cilia4 ,propelled  
by  these1 it swims about for a longer  
or shorter time1 but at length comes  to
 a state of rest and gradually grows    
into a ,coleochaete4 ,moreover1 as  in  
the ,peronospora1 conjugation may take  
place and result in an  oospore2 the    
contents of which divide and are set    
free as monadiform  germs4    ,if the   
whole history of the zoospores of       
,peronospora and of  ,coleochaete were  
unknown1 they would undoubtedly be      
classed among  ,monads with the same    
right as ,heteromita2 why then may not  
,heteromita be a plant1 even though the 

cycle of forms through which it  passes 
shows no terms quite so complex as those
 which occur in  ,peronospora and       
,coleochaete8 ,and1 in fact1 there are  
some green  organisms1 in every respect 
characteristically plants1 such as      
,chlamydomonas1 and the common ,volvox1 
or so-called ,globe  animalcule1 which  
run through a cycle of forms of just the
 same simple  character as those of     
,heteromita4    ,the name of            
,chlamydomonas is applied to certain    
microscopic green  bodies1 each of which
 consists of a protoplasmic central     
substance  invested by a structureless  
sac4 ,the latter contains cellulose1 as 
in  ordinary plants2 and the chlorophyll
 which gives the green colour enables   
the ,chlamydomonas to decompose carbonic
 acid and fix carbon as they do4  ,two  
long cilia protrude through the         
cell-wall1 and effect the rapid         
locomotion of this monad1 which1 in all 
respects except its mobility1  is       
characteristically a plant4 ,under      

ordinary circumstances1 the             
,chlamydomonas multiplies by simple     
fission1 each splitting into two or     
into four parts1 which separate and     
become independent organisms4           
,sometimes1 however1 the ,chlamydomonas 
divides into eight parts1 each of  which
 is provided with four instead of two   
cilia4 ,these zoospores  conjugate in   
pairs1 and give rise to quiescent       
bodies1 which multiply by  division1    
find eventually pass into the active    
state4    ,thus1 so far as outward form 
and the general character of the cycle  
of  modifications1 through which the    
organism passes in the course of its    
life1 are concerned1 the resemblance    
between ,chlamydomonas and  ,heteromita 
is of the closest description4 ,and on  
the face of the matter  there is no     
ground for refusing to admit that       
,heteromita may be related  to          
,chlamydomonas1 as the colourless fungus
 is to the green alga4  ,volvox may be  
compared to a hollow sphere1 the wall of

 which is made up  of coherent          
,chlamydomonads2 and which progresses   
with a rotating motion  effected by the 
paddling of the multitudinous pairs of  
cilia which  project from its surface4  
,each ,volvox-monad1 moreover1 possesses
 a red  pigment spot1 like the simplest 
form of eye known among animals4 ,the   
methods of fissive multiplication and of
 conjugation observed in the  monads of 
this locomotive globe are essentially   
similar to those observed  in           
,chlamydomonas2 and1 though a hard      
battle has been fought over it1  ,volvox
 is now finally surrendered to the      
,botanists4    ,thus there is really no 
reason why ,heteromita may not be a     
plant2 and  this conclusion would be    
very satisfactory1 if it were not       
equally easy  to show that there is     
really no reason why it should not be an
 animal4  ,for there are numerous       
organisms presenting the closest        
resemblance to  ,heteromita1 and1 like  
it1 grouped under the general name of   

,monads1  which1 nevertheless1 can be   
observed to take in solid nutriment1 and
  which1 therefore1 have a virtual1 if  
not an actual1 mouth and digestive      
cavity1 and thus come under ,cuvier's   
definition of an animal4 ,numerous      
forms of such animals have been         
described by ,ehrenberg1 ,dujardin1 ,h4 
,james ,clark1 and other writers on the 
,infusoria4 ,indeed1 in another         
infusion of hay in which my ,heteromita 
lens occurred1 there were  innumerable  
such infusorial animalcules belonging to
 the well-known  species ,colpoda       
cucullus4#f    ,footnote #f3            
,excellently described by ,stein1 almost
 all of whose  statements ,i have       
verified4    ,full-sized specimens of   
this animalcule attain a length of      
between #a_/cjj  or #a_/djj of an inch1 
so that it may have ten times the length
 and a  thousand times the mass of a    
,heteromita4 ,in shape1 it is not       
altogether  unlike ,heteromita4 ,the    
small end1 however1 is not produced into

 one  long cilium1 but the general      
surface of the body is covered with     
small  actively vibrating ciliary       
organs1 which are only longest at the   
small  end4 ,at the point which answers 
to that from which the two cilia arise  
in  ,heteromita1 there is a conical     
depression1 the mouth2 and1 in young    
specimens1 a tapering filament1 which   
reminds one of the posterior cilium  of 
,heteromita1 projects from this region4 
,the body consists of a soft granular   
protoplasmic substance1 the middle  of  
which is occupied by a large oval mass  
called the nucleus2 while1 at  its      
hinder end1 is a contractile vacuole1   
conspicuous by its regular  rhythmic    
appearances and disappearances4         
,obviously1 although the  ,colpoda is   
not a monad1 it differs from one only in
 subordinate  details4 ,moreover1 under 
certain conditions1 it becomes          
quiescent1  incloses itself in a        
delicate case or cyst1 and then divides 
into two1  four1 or more portions1 which

 are eventually set free and swim about 
as  active ,colpodoe4    ,but this      
creature is an unmistakable animal1 and 
full-sized ,colpodoe  may be fed as     
easily as one feeds chickens4 ,it is    
only needful to diffuse  very finely    
ground carmine through the water in     
which they live1 and1 in  a very short  
time1 the bodies of the ,colpodoe are   
stuffed with the  deeply-coloured       
granules of the pigment4    ,and if this
 were not sufficient evidence of the    
animality of ,colpoda1  there comes the 
fact that it is even more similar to    
another well-known  animalcule1         
,paramoecium1 than it is to a monad4    
,but ,paramoecium is so  huge a creature
 compared with those hitherto           
discussed--it reaches #a_/abj  of an    
inch or more in length--that there is no
 difficulty in making out  its          
organisation in detail2 and in proving  
that it is not only an animal1  but that
 it is an animal which possesses a      
somewhat complicated  organisation4 ,for

 example1 the surface layer of its body 
is different in  structure from the     
deeper parts4 ,there are two contractile
 vacuoles1 from  each of which radiates 
a system of vessel-like canals2 and not 
only is  there a conical depression     
continuous with a tube1 which serve as  
mouth  and gullet1 but the food ingested
 takes a definite course1 and refuse is 
rejected from a definite region4        
,nothing is easier than to feed these   
animals1 and to watch the particles of  
indigo or carmine accumulate at  the    
lower end of the gullet4 ,from this they
 gradually project1 surrounded  by a    
ball of water1 which at length passes   
with a jerk1 oddly simulating  a gulp1  
into the pulpy central substance of the 
body1 there to circulate  up one side   
and down the other1 until its contents  
are digested and  assimilated4          
,nevertheless1 this complex animal      
multiplies by division1 as  the monad   
does1 and1 like the monad1 undergoes    
conjugation4 ,it stands in  the same    

relation to ,heteromita on the animal   
side1 as ,coleochaete  does on the plant
 side4 ,start from either1 and such an  
insensible series  of gradations leads  
to the monad that it is impossible to   
say at any  stage of the progress where 
the line between the animal and the     
plant  must be drawn4    ,there is      
reason to think that certain organisms  
which pass through a  monad stage of    
existence1 such as the ,myxomycetes1    
are1 at one time of  their lives1       
dependent upon external sources for     
their protein matter1 or  are animals2  
and1 at another period1 manufacture it1 
or are plants4 ,and  seeing that the    
whole progress of modern investigation  
is in favour of  the doctrine of        
continuity1 it is a fair and probable   
speculation--though  only a             
speculation--that1 as there are some    
plants which can manufacture  protein   
out of such apparently intractable      
mineral matters as carbonic  acid1      
water1 nitrate of ammonia1 metallic and 

earthy salts2 while others  need to be  
supplied with their carbon and nitrogen 
in the somewhat less  raw form of       
tartrate of ammonia and allied          
compounds2 so there may be yet  others1 
as is possibly the case with the true   
parasitic plants1 which can  only manage
 to put together materials still better 
prepared--still more  nearly            
approximated to protein--until we arrive
 at such organisms as the               
,psorospermioe and the ,panhistophyton1 
which are as much animal as  vegetable  
in structure1 but are animal in their   
dependence on other  organisms for their
 food4    ,the singular circumstance    
observed by ,meyer1 that the ,torula of 
yeast1  though an indubitable plant1    
still flourishes most vigorously when   
supplied with the complex nitrogenous   
substance1 pepsin2 the probability  that
 the ,peronospora is nourished directly 
by the protoplasm of the  potato-plant2 
and the wonderful facts which have      
recently been brought to  light         

respecting insectivorous plants1 all    
favour this view2 and tend to  the      
conclusion that the difference between  
animal and plant is one of  degree      
rather than of kind1 and that the       
problem whether1 in a given  case1 an   
organism is an animal or a plant1 may be
 essentially insoluble4        ,,vii    
,a ,,lobster2 ,,or1 ,,the ,,study ,,of  
,,zoology    #ahfa    ,natural history  
is the name familiarly applied to the   
study of the  properties of such natural
 bodies as minerals1 plants1 and        
animals2 the  sciences which embody the 
knowledge man has acquired upon these   
subjects  are commonly termed ,natural  
,sciences1 in contradistinction to other
 so-  called physical sciences2 and     
those who devote themselves especially  
to  the pursuit of such sciences have   
been and are commonly termed            
,naturalists4    ,linnaeus was a        
naturalist in this wide sense1 and his  
,systema ,naturae was  a work upon      
natural history1 in the broadest        

acceptation of the term2 in  it1 that   
great methodising spirit embodied all   
that was known in his time  of the      
distinctive characters of minerals1     
animals1 and plants4 ,but the  enormous 
stimulus which ,linnaeus gave to the    
investigation of nature soon  rendered  
it impossible that any one man should   
write another ,systema  ,naturae1 and   
extremely difficult for any one to      
become even a naturalist  such as       
,linnaeus was4    ,great as have been   
the advances made by all the three      
branches of  science1 of old included   
under the title of natural history1     
there can be  no doubt that zoology and 
botany have grown in an enormously      
greater  ratio than mineralogy2 and     
hence1 as ,i suppose1 the name of       
natural  history has gradually become   
more and more definitely attached to    
these  prominent divisions of the       
subject1 and by naturalist people have  
meant  more and more distinctly to imply
 a student of the structure and function

  of living beings4    ,however this may
 be1 it is certain that the advance of  
knowledge has  gradually widened the    
distance between mineralogy and its old 
associates1  while it has drawn zoology 
and botany closer together2 so that of  
late  years it has been found convenient
 7and indeed necessary7 to associate    
the sciences which deal with vitality   
and all its phenomena under the  common 
head of biology2 and the biologists have
 come to repudiate any                  
blood-relationship with their           
foster-brothers1 the mineralogists4     
,certain broad laws have a general      
application throughout both the animal  
and the vegetable worlds1 but the ground
 common to these kingdoms of  nature is 
not of very wide extent1 and the        
multiplicity of details is so  great1   
that the student of living beings finds 
himself obliged to devote  his attention
 exclusively either to the one or the   
other4 ,if he elects to  study plants1  
under any aspect1 we know at once what  

to call him4 ,he is a  botanist1 and his
 science is botany4 ,but if the         
investigation of animal  life be his    
choice1 the name generally applied to   
him will vary according  to the kind of 
animals he studies1 or the particular   
phenomena of animal  life to which he   
confines his attention4 ,if the study of
 man is his  object1 he is called an    
anatomist1 or a physiologist1 or an     
ethnologist2  but if he dissects        
animals1 or examines into the mode in   
which their  functions are performed1 he
 is a comparative anatomist or          
comparative  physiologist4 ,if he turns 
his attention to fossil animals1 he is a
  palaeontologist4 ,if his mind is more 
particularly directed to the specific   
description1 discrimination1            
classification1 and distribution of     
animals1  he is termed a zoologist4     
,for the purpose of the present         
discourse1 however1 ,i shall recognise  
none  of these titles save the last1    
which ,i shall employ as the equivalent 

of  botanist1 and ,i shall use the term 
zoology is denoting the whole doctrine  
of animal life1 in contradistinction to 
botany1 which signifies the whole       
doctrine of vegetable life4    ,employed
 in this sense1 zoology1 like botany1 is
 divisible into three  great but        
subordinate sciences1 morphology1       
physiology1 and distribution1  each of  
which may1 to a very great extent1 be   
studied independently of  the other4    
,zoological morphology is the doctrine  
of animal form or structure4  ,anatomy  
is one of its branches2 development is  
another2 while  classification is the   
expression of the relations which       
different animals  bear to one another1 
in respect of their anatomy and their   
development4    ,zoological distribution
 is the study of animals in relation to 
the  terrestrial conditions which obtain
 now1 or have obtained at any previous  
epoch of the earth's history4           
,zoological physiology1 lastly1 is the  
doctrine of the functions or  actions of

 animals4 ,it regards animal bodies as  
machines impelled by  certain forces1   
and performing an amount of work which  
can be expressed  in terms of the       
ordinary forces of nature4 ,the final   
object of physiology  is to deduce the  
facts of morphology1 on the one hand1   
and those of  distribution on the other1
 from the laws of the molecular forces  
of  matter4    ,such is the scope of    
zoology4 ,but if ,i were to content     
myself with the  enunciation of these   
dry definitions1 ,i should ill exemplify
 that method  of teaching this branch of
 physical science1 which it is my chief 
business to-night to recommend4 ,let us 
turn away then from abstract            
definitions4 ,let us take some concrete 
living thing1 some animal1 the  commoner
 the better1 and let us see how the     
application of common sense  and common 
logic to the obvious facts it presents1 
inevitably leads us  into all these     
branches of zoological science4    ,i   
have before me a lobster4 ,when ,i      

examine it1 what appears to be the  most
 striking character it presents8 ,why1  
,i observe that this part which  we call
 the tail of the lobster1 is made up of 
six distinct hard rings  and a seventh  
terminal piece4 ,if ,i separate one of  
the middle rings1 say  the third1 ,i    
find it carries upon its under surface a
 pair of limbs or  appendages1 each of  
which consists of a stalk and two       
terminal pieces4 ,so  that ,i can       
represent a transverse section of the   
ring and its appendages  upon the       
diagram board in this way4    ,if ,i now
 take the fourth ring1 ,i find it has   
the same structure1 and so  have the    
fifth and the second2 so that1 in each  
of these divisions of the  tail1 ,i find
 parts which correspond with one        
another1 a ring and two  appendages2 and
 in each appendage a stalk and two end  
pieces4 ,these  corresponding parts are 
called1 in the technical language of    
anatomy1  homologous parts4 ,the ring of
 the third division is the homologue of 

the ring of the fifth1 the appendage of 
the former is the homologue of  the     
appendage of the latter4 ,and1 as each  
division exhibits corresponding  parts  
in corresponding places1 we say that all
 the divisions are  constructed upon the
 same plan4 ,but now let us consider the
 sixth  division4 ,it is similar to1 and
 yet different from1 the others4 ,the   
ring  is essentially the same as in the 
other divisions2 but the appendages     
look at first as if they were very      
different2 and yet when we regard them  
closely1 what do we find8 ,a stalk and  
two terminal divisions1 exactly as  in  
the others1 but the stalk is very short 
and very thick1 the terminal  divisions 
are very broad and flat1 and one of them
 is divided into two  pieces4    ,i may 
say1 therefore1 that the sixth segment  
is like the others in plan1  but that it
 is modified in its details4    ,the    
first segment is like the others1 so far
 as its ring is concerned1  and though  
its appendages differ from any of those 

yet examined in the  simplicity of their
 structure1 parts corresponding with the
 stem and one  of the divisions of the  
appendages of the other segments can be 
readily  discerned in them4    ,thus it 
appears that the lobster's tail is      
composed of a series of  segments which 
are fundamentally similar1 though each  
presents peculiar  modifications of the 
plan common to all4 ,but when ,i turn to
 the forepart  of the body ,i see1 at   
first1 nothing but a great shield-like  
shell1  called technically the carapace1
 ending in front in a sharp spine1 on   
either side of which are the curious    
compound eyes1 set upon the ends of     
stout movable stalks4 ,behind these1 on 
the under side of the body1 are  two    
pairs of long feelers1 or antennae1     
followed by six pairs of jaws  folded   
against one another over the mouth1 and 
five pairs of legs1 the  foremost of    
these being the great pinchers1 or      
claws1 of the lobster4    ,it looks1 at 
first1 a little hopeless to attempt to  

find in this complex  mass a series of  
rings1 each with its pair of appendages1
 such as ,i have  shown you in the      
abdomen1 and yet it is not difficult to 
demonstrate  their existence4 ,strip off
 the legs1 and you will find that each  
pair is  attached to a very definite    
segment of the under wall of the body2  
but  these segments1 instead of being   
the lower parts of free rings1 as in the
  tail1 are such parts of rings which   
are all solidly united and bound        
together2 and the like is true of the   
jaws1 the feelers1 and the eye-  stalks1
 every pair of which is borne upon its  
own special segment4 ,thus  the         
conclusion is gradually forced upon us1 
that the body of the lobster  is        
composed of as many rings as there are  
pairs of appendages1 namely1  twenty in 
all1 but that the six hindmost rings    
remain free and movable1  while the     
fourteen front rings become firmly      
soldered together1 their  backs forming 
one continuous shield--the carapace4    

,unity of plan1 diversity in execution1 
is the lesson taught by the study  of   
the rings of the body1 and the same     
instruction is given still more         
emphatically by the appendages4 ,if ,i  
examine the outermost jaw ,i find it    
consists of three distinct portions1 an 
inner1 a middle1 and an outer1  mounted 
upon a common stem2 and if ,i compare   
this jaw with the legs  behind it1 or   
the jaws in front of it1 ,i find it     
quite easy to see1 that1  in the legs1  
it is the part of the appendage which   
corresponds with the  inner division1   
which becomes modified into what we know
 familiarly as  the leg1 while the      
middle division disappears1 and the     
outer division  is hidden under the     
carapace4 ,nor is it more difficult to  
discern that1  in the appendages of the 
tail1 the middle division appears again 
and the  outer vanishes2 while1 on the  
other hand1 in the foremost jaw1 the so-
  called mandible1 the inner division   
only is left2 and1 in the same way1  the

 parts of the feelers and of the        
eye-stalks can be identified with  those
 of the legs and jaws4    ,but whither  
does all this tend8 ,to the very        
remarkable conclusion that a  unity of  
plan1 of the same kind as that          
discoverable in the tail or  abdomen of 
the lobster1 pervades the whole         
organisation of its skeleton1  so that  
,i can return to the diagram            
representing any one of the rings of    
the tail1 which ,i drew upon the board1 
and by adding a third division to  each 
appendage1 ,i can use it as a sort of   
scheme or plan of any ring of  the body4
 ,i can give names to all the parts of  
that figure1 and then if ,i  take any   
segment of the body of the lobster1 ,i  
can point out to you  exactly1 what     
modification the general plan has       
undergone in that  particular segment2  
what part has remained movable1 and what
 has become  fixed to another2 what has 
been excessively developed and          
metamorphosed  and what has been        

suppressed4    ,but ,i imagine ,i hear  
the question1 ,how is all this to be    
tested8 ,no doubt  it is a pretty and   
ingenious way of looking at the         
structure of any  animal2 but is it     
anything more8 ,does ,nature            
acknowledge1 in any deeper  way1 this   
unity of plan we seem to trace8    ,the 
objection suggested by these questions  
is a very valid and important  one1 and 
morphology was in an unsound state so   
long as it rested upon the  mere        
perception of the analogies which obtain
 between fully formed parts4  ,the      
unchecked ingenuity of speculative      
anatomists proved itself fully          
competent to spin any number of         
contradictory hypotheses out of the same
  facts1 and endless morphological      
dreams threatened to supplant scientific
  theory4    ,happily1 however1 there is
 a criterion of morphological truth1 and
 a sure  test of all homologies4 ,our   
lobster has not always been what we see 
it2  it was once an egg1 a semifluid    

mass of yolk1 not so big as a pin's     
head1  contained in a transparent       
membrane1 and exhibiting not the least  
trace  of any one of those organs1 the  
multiplicity and complexity of which1 in
  the adult1 are so surprising4 ,after a
 time1 a delicate patch of cellular     
membrane appeared upon one face of this 
yolk1 and that patch was the  foundation
 of the whole creature1 the clay out of 
which it would be  moulded4 ,gradually  
investing the yolk1 it became subdivided
 by transverse  constrictions into      
segments1 the forerunners of the rings  
of the body4  ,upon the ventral surface 
of each of the rings thus sketched out1 
a pair  of bud-like prominences made    
their appearance--the rudiments of the  
appendages of the ring4 ,at first1 all  
the appendages were alike1 but1 as  they
 grew1 most of them became distinguished
 into a stem and two terminal           
divisions1 to which1 in the middle part 
of the body1 was added a third  outer   
division2 and it was only at a later    

period1 that by the  modification1 or   
absorption1 of certain of these         
primitive constituents1  the limbs      
acquired their perfect form4    ,thus   
the study of development proves that the
 doctrine of unity of plan  is not      
merely a fancy1 that it is not merely   
one way of looking at the  matter1 but  
that it is the expression of deep-seated
 natural facts4 ,the  legs and jaws of  
the lobster may not merely be regarded  
as modifications  of a common type1--in 
fact and in nature they are so1--the leg
 and the  jaw of the young animal being1
 at first1 indistinguishable4    ,these 
are wonderful truths1 the more so       
because the zoologist finds them  to be 
of universal application4 ,the          
investigation of a polype1 of a  snail1 
of a fish1 of a horse1 or of a man1     
would have led us1 though by a  less    
easy path1 perhaps1 to exactly the same 
point4 ,unity of plan  everywhere lies  
hidden under the mask of diversity of   
structure--the  complex is everywhere   

evolved out of the simple4 ,every animal
 has at  first the form of an egg1 and  
every animal and every organic part1 in 
reaching its adult state1 passes through
 conditions common to other  animals and
 other adult parts2 and this leads me to
 another point4 ,i have  hitherto spoken
 as if the lobster were alone in the    
world1 but1 as ,i need  hardly remind   
you1 there are myriads of other animal  
organisms4 ,of these1  some1 such as    
men1 horses1 birds1 fishes1 snails1     
slugs1 oysters1 corals1  and sponges1   
are not in the least like the lobster4  
,but other animals1  though they may    
differ a good deal from the lobster1 are
 yet either very  like it1 or are like  
something that is like it4 ,the cray    
fish1 the rock  lobster1 and the prawn1 
and the shrimp1 for example1 however    
different1  are yet so like lobsters1   
that a child would group them as of the 
lobster  kind1 in contradistinction to  
snails and slugs2 and these last again  
would form a kind by themselves1 in     

contradistinction to cows1 horses1  and 
sheep1 the cattle kind4    ,but this    
spontaneous grouping into kinds is the  
first essay of the  human mind at       
classification1 or the calling by a     
common name of those  things that are   
alike1 and the arranging them in such a 
manner as best to  suggest the sum of   
their likenesses and unlikenesses to    
other things4    ,those kinds which     
include no other subdivisions than the  
sexes1 or  various breeds1 are called1  
in technical language1 species4 ,the    
,english  lobster is a species1 our cray
 fish is another1 our prawn is another4 
,in  other countries1 however1 there are
 lobsters1 cray fish1 and prawns1 very  
like ours1 and yet presenting sufficient
 differences to deserve  distinction4   
,naturalists1 therefore1 express this   
resemblance and this  diversity by      
grouping them as distinct species of the
 same genus4 ,but  the lobster and the  
cray fish1 though belonging to distinct 
genera1 have  many features in common1  

and hence are grouped together in an    
assemblage  which is called a family4   
,more distant resemblances connect the  
lobster  with the prawn and the crab1   
which are expressed by putting all these
  into the same order4 ,again1 more     
remote1 but still very definite1        
resemblances unite the lobster with the 
woodlouse1 the king crab1 the  water    
flea1 and the barnacle1 and separate    
them from all other animals2  whence    
they collectively constitute the larger 
group1 or class1  ,crustacea4 ,but the  
,crustacea exhibit many peculiar        
features in common  with insects1       
spiders1 and centipedes1 so that these  
are grouped into the  still larger      
assemblage or province ,articulata2 and1
 finally1 the  relations which these    
have to worms and other lower animals1  
are  expressed by combining the whole   
vast aggregate into the sub-kingdom of  
,annulosa4    ,if ,i had worked my way  
from a sponge instead of a lobster1 ,i  
should have  found it associated1 by    

like ties1 with a great number of other 
animals  into the sub-kingdom ,protozoa2
 if ,i had selected a fresh-water polype
  or a coral1 the members of what       
naturalists term the sub-kingdom        
,coelenterata1 would have grouped       
themselves around my type2 had a snail  
been chosen1 the inhabitants of all     
univalve and bivalve1 land and water1   
shells1 the lamp shells1 the squids1 and
 the sea-mat would have gradually       
linked themselves on to it as members of
 the same sub-kingdom of  ,mollusca2 and
 finally1 starting from man1 ,i should  
have been compelled  to admit first1 the
 ape1 the rat1 the horse1 the dog1 into 
the same  class2 and then the bird1 the 
crocodile1 the turtle1 the frog1 and the
  fish1 into the same sub-kingdom of    
,vertebrata4    ,and if ,i had followed 
out all these various lines of          
classification  fully1 ,i should        
discover in the end that there was no   
animal1 either  recent or fossil1 which 
did not at once fall into one or other  

of these  sub-kingdoms4 ,in other words1
 every animal is organised upon one or  
other  of the five1 or more1 plans1 the 
existence of which renders our          
classification possible4 ,and so        
definitely and precisely marked is the  
structure of each animal1 that1 in the  
present state of our knowledge1  there  
is not the least evidence to prove that 
a form1 in the slightest  degree        
transitional between any of the two     
groups ,vertebrata1 ,annulosa1          
,mollusca1 and ,coelenterata1 either    
exists1 or has existed1 during that     
period of the earth's history which is  
recorded by the geologist4#a            
,nevertheless1 you must not for a moment
 suppose1 because no such  transitional 
forms are known1 that the members of the
 sub-kingdoms are  disconnected from1 or
 independent of1 one another4 ,on the   
contrary1 in  their earliest condition  
they are all similar1 and the primordial
 germs  of a man1 a dog1 a bird1 a fish1
 a beetle1 a snail1 and a polype are1 in

  no essential structural respects1     
distinguishable4    ,footnote #a3 ,the  
different grouping necessitated by later
 knowledge does  not affect the         
principle of the argument4--#ahid4      
,in this broad sense1 it may with truth 
be said1 that all living animals1  and  
all those dead faunae which geology     
reveals1 are bound together by an       
all-pervading unity of organisation1 of 
the same character1 though not  equal in
 degree1 to that which enables us to    
discern one and the same  plan amidst   
the twenty different segments of a      
lobster's body4 ,truly it  has been     
said1 that to a clear eye the smallest  
fact is a window through  which the     
,infinite may be seen4    ,turning from 
these purely morphological              
considerations1 let us now  examine into
 the manner in which the attentive study
 of the lobster  impels us into other   
lines of research4    ,lobsters are     
found in all the ,european seas2 but on 
the opposite shores  of the ,atlantic   

and in the seas of the southern         
hemisphere they do not  exist4 ,they    
are1 however1 represented in these      
regions by very closely  allied1 but    
distinct forms--the ,homarus ,americanus
 and the ,homarus  ,capensis3 so that we
 may say that the ,european has one     
species of  ,homuarus2 the ,american1   
another2 the ,african1 another2 and thus
 the  remarkable facts of geographical  
distribution begin to dawn upon us4     
,again1 if we examine the contents of   
the earth's crust1 we shall find in  the
 latter of those deposits1 which have   
served as the great burying  grounds of 
past ages1 numberless lobster-like      
animals1 but none so  similar to our    
living lobster as to make zoologists    
sure that they  belonged even to the    
same genus4 ,if we go still further back
 in time1 we  discover1 in the oldest   
rocks of all1 the remains of animals1   
constructed  on the same general plan as
 the lobster1 and belonging to the same 
great  group of ,crustacea2 but for the 

most part totally different from the    
lobster1 and indeed from any other      
living form of crustacean2 and thus we  
gain a notion of that successive change 
of the animal population of the  globe1 
in past ages1 which is the most striking
 fact revealed by geology4    ,consider1
 now1 where our inquiries have led us4  
,we studied our type  morphologically1  
when we determined its anatomy and its  
development1 and  when comparing it1 in 
these respects1 with other animals1 we  
made out its  place in a system of      
classification4 ,if we were to examine  
every animal  in a similar manner1 we   
should establish a complete body of     
zoological  morphology4    ,again1 we   
investigated the distribution of our    
type in space and in time1  and1 if the 
like had been done with every animal1   
the sciences of  geographical and       
geological distribution would have      
attained their limit4    ,but you will  
observe one remarkable circumstance1    
that1 up to this point1  the question of

 the life of these organisms has not    
come under  consideration4 ,morphology  
and distribution might be studied almost
 as  well1 if animals and plants were a 
peculiar kind of crystals1 and          
possessed none of those functions which 
distinguish living beings so            
remarkably4 ,but the facts of morphology
 and distribution have to be  accounted 
for1 and the science1 the aim of which  
it is to account for  them1 is          
,physiology4    ,let us return to our   
lobster once more4 ,if we watched the   
creature in its  native element1 we     
should see it climbing actively the     
submerged rocks1  among which it        
delights to live1 by means of its strong
 legs2 or swimming  by powerful strokes 
of its great tail1 the appendages of the
 sixth joint  of which are spread out   
into a broad fan-like ,propeller3 seize 
it1 and it  will show you that its great
 claws are no mean weapons of offence2  
suspend a piece of carrion among its    
haunts1 and it will greedily devour  it1

 tearing and crushing the flesh by means
 of its multitudinous jaws4    ,suppose 
that we had known nothing of the lobster
 but as an inert mass1 an  organic      
crystal1 if ,i may use the phrase1 and  
that we could suddenly see  it exerting 
all these powers1 what wonderful new    
ideas and new questions  would arise in 
our minds6 ,the great new question would
 be1 ,how does all  this take place8 the
 chief new idea would be1 the idea of   
adaptation to  purpose1--the notion1    
that the constituents of animal bodies  
are not mere  unconnected parts1 but    
organs working together to an end4 ,let 
us consider  the tail of the lobster    
again from this point of view4          
,morphology has  taught us that it is a 
series of segments composed of          
homologous parts1  which undergo various
 modifications--beneath and through     
which a common  plan of formation is    
discernible4 ,but if ,i look at the same
 part  physiologically1 ,i see that it  
is a most beautifully constructed organ 

of  locomotion1 by means of which the   
animal can swiftly propel itself either 
backwards or forwards4    ,but how is   
this remarkable propulsive machine made 
to perform its  functions8 ,if ,i were  
suddenly to kill one of these animals   
and to take  out all the soft parts1 ,i 
should find the shell to be perfectly   
inert1 to  have no more power of moving 
itself than is possessed by the         
machinery of  a mill when disconnected  
from its steam-engine or water-wheel4   
,but if ,i  were to open it1 and take   
out the viscera only1 leaving the white 
flesh1  ,i should perceive that the     
lobster could bend and extend its tail  
as well  as before4 ,if ,i were to cut  
off the tail1 ,i should cease to find   
any  spontaneous motion in it2 but on   
pinching any portion of the flesh1 ,i   
should observe that it underwent a very 
curious change--each fibre  becoming    
shorter and thicker4 ,by this act of    
contraction1 as it is  termed1 the parts
 to which the ends of the fibre are     

attached are1 of  course1 approximated2 
and according to the relations of their 
points of  attachment to the centres of 
motions of the different rings1 the     
bending  or the extension of the tail   
results4 ,close observation of the      
newly-  opened lobster would soon show  
that all its movements are due to the   
same  cause--the shortening and         
thickening of these fleshy fibres1 which
 are  technically called muscles4       
,here1 then1 is a capital fact4 ,the    
movements of the lobster are due to     
muscular contractility4 ,but why does a 
muscle contract at one time and  not at 
another8 ,why does one whole group of   
muscles contract when the  lobster      
wishes to extend his tail1 and another  
group when he desires to  bend it8 ,what
 is it originates1 directs1 and controls
 the motive power8    ,experiment1 the  
great instrument for the ascertainment  
of truth in  physical science1 answers  
this question for us4 ,in the head of   
the  lobster there lies a small mass of 

that peculiar tissue which is known as  
nervous substance4 ,cords of similar    
matter connect his brain of the         
lobster1 directly or indirectly1 with   
the muscles4 ,now1 if these             
communicating cords are cut1 the brain  
remaining entire1 the power of  exerting
 what we call voluntary motion in the   
parts below the section is  destroyed2  
and1 on the other hand1 if1 the cords   
remaining entire1 the  brain mass be    
destroyed1 the same voluntary mobility  
is equally lost4  ,whence the inevitable
 conclusion is1 that the power of       
originating these  motions resides in   
the brain and is propagated along the   
nervous cords4    ,in the higher animals
 the phenomena which attend this        
transmission have  been investigated1   
and the exertion of the peculiar energy 
which resides  in the nerves has been   
found to be accompanied by a disturbance
 of the  electrical state of their      
molecules4    ,if we could exactly      
estimate the signification of this      

disturbance2 if we  could obtain the    
value of a given exertion of nerve force
 by determining  the quantity of        
electricity1 or of heat1 of which it is 
the equivalent2  if we could ascertain  
upon what arrangement1 or other         
condition of the  molecules of matter1  
the manifestation of the nervous and    
muscular  energies depends 7and         
doubtless science will some day or other
 ascertain  these points71 physiologists
 would have attained their ultimate goal
 in  this direction2 they would have    
determined the relation of the motive   
force of animals to the other forms of  
force found in nature2 and if the  same 
process had been successfully performed 
for all the operations which  are       
carried on in1 and by1 the animal frame1
 physiology would be perfect1  and the  
facts of morphology and distribution    
would be deducible from the  laws which 
physiologists had established1 combined 
with those determining  the condition of
 the surrounding universe4    ,there is 

not a fragment of the organism of this  
humble animal whose study  would not    
lead us into regions of thought as large
 as those which ,i have  briefly opened 
up to you2 but what ,i have been saying1
 ,i trust1 has not  only enabled you to 
form a conception of the scope and      
purport of  zoology1 but has given you  
an imperfect example of the manner in   
which1  in my opinion1 that science1 or 
indeed any physical science1 may be best
  taught4 ,the great matter is1 to make 
teaching real and practical1 by  fixing 
the attention of the student on         
particular facts2 but at the same  time 
it should be rendered broad and         
comprehensive1 by constant reference  to
 the generalisations of which all       
particular facts are illustrations4     
,the lobster has served as a type of the
 whole animal kingdom1 and its  anatomy 
and physiology have illustrated for us  
some of the greatest  truths of biology4
 ,the student who has once seen for     
himself the facts  which ,i have        

described1 has had their relations      
explained to him1 and has  clearly      
comprehended them1 has1 so far1 a       
knowledge of zoology1 which is  real and
 genuine1 however limited it may be1 and
 which is worth more than  all the mere 
reading knowledge of the science he     
could ever acquire4 ,his  zoological    
information is1 so far1 knowledge and   
not mere hearsay4    ,and if it were nay
 business to fit you for the certificate
 in zoological  science granted by this 
department1 ,i should pursue a course   
precisely  similar in principle to that 
which ,i have taken to-night4 ,i should 
select  a fresh-water sponge1 a         
fresh-water polype or a ,cyanoea1 a     
fresh-water  mussel1 a lobster1 a fowl1 
as types of the five primary divisions  
of the  animal kingdom4 ,i should       
explain their structure very fully1 and 
show how  each illustrated the great    
principles of zoology4 ,having gone very
  carefully and fully over this ground1 
,i should feel that you had a safe      

foundation1 and ,i should then take you 
in the same way1 but less  minutely1    
over similarly selected illustrative    
types of the classes2 and  then ,i      
should direct your attention to the     
special forms enumerated under  the head
 of types1 in this syllabus1 and to the 
other facts there  mentioned4    ,that  
would1 speaking generally1 be my plan4  
,but ,i have undertaken to  explain to  
you the best mode of acquiring and      
communicating a knowledge  of zoology1  
and you may therefore fairly ask me for 
a more detailed and  precise account of 
the manner in which ,i should propose to
 furnish you  with the information ,i   
refer to4    ,my own impression is1 that
 the best model for all kinds of        
training in  physical science is that   
afforded by the method of teaching      
anatomy1 in  use in the medical schools4
 ,this method consists of three         
elements--  lectures1 demonstrations1   
and examinations4    ,the object of     
lectures is1 in the first place1 to     

awaken the attention  and excite the    
enthusiasm of the student2 and this1 ,i 
am sure1 may be  effected to a far      
greater extent by the oral discourse and
 by the  personal influence of a        
respected teacher than in any other way4
  ,secondly1 lectures have the double   
use of guiding the student to the       
salient points of a subject1 and at the 
same time forcing him to attend  to the 
whole of it1 and not merely to that part
 which takes his fancy4  ,and lastly1   
lectures afford the student the         
opportunity of seeking  explanations of 
those difficulties which will1 and      
indeed ought to1 arise  in the course of
 his studies4    ,what books shall ,i   
read8 is a question constantly put by   
the student to  the teacher4 ,my reply  
usually is1 ,none3 write your notes out 
carefully  and fully2 strive to         
understand them thoroughly2 come to me  
for the  explanation of anything you    
cannot understand2 and ,i would rather  
you did  not distract your mind by      

reading4 ,a properly composed course of 
lectures ought to contain fully as much 
matter as a student can  assimilate in  
the time occupied by its delivery2 and  
the teacher should  always recollect    
that his business is to feed1 and not to
 cram the  intellect4 ,indeed1 ,i       
believe that a student who gains from a 
course of  lectures the simple habit of 
concentrating his attention upon a      
definitely limited series of facts1     
until they are thoroughly mastered1  has
 made a step of immeasurable importance4
    ,but1 however good lectures may be1 
and however extensive the course of     
reading by which they are followed up1  
they are but accessories to the  great  
instrument of scientific                
teaching--demonstration4 ,if ,i insist  
unweariedly1 nay fanatically1 upon the  
importance of physical science as  an   
educational agent1 it is because the    
study of any branch of science1  if     
properly conducted1 appears to me to    
fill up a void left by all other  means 

of education4 ,i have the greatest      
respect and love for literature2        
nothing would grieve me more than to see
 literary training other than a  very   
prominent branch of education3 indeed1  
,i wish that real literary  discipline  
were far more attended to than it is2   
but ,i cannot shut my  eyes to the fact1
 that there is a vast difference between
 men who have  had a purely literary1   
and those who have had a sound          
scientific1  training4    ,seeking for  
the cause of this difference1 ,i imagine
 ,i can find it in the  fact that1 in   
the world of letters1 learning and      
knowledge are one1 and  books are the   
source of both2 whereas in science1 as  
in life1 learning  and knowledge are    
distinct1 and the study of things1 and  
not of books1 is  the source of the     
latter4    ,all that literature has to  
bestow may be obtained by reading and by
  practical exercise in writing and in  
speaking2 but ,i do not exaggerate  when
 ,i say1 that none of the best gifts of 

science are to be won by these  means4  
,on the contrary1 the great benefit     
which a scientific education  bestows1  
whether is training or as knowledge1 is 
dependent upon the  extent to which the 
mind of the student is brought into     
immediate contact  with facts--upon the 
degree to which he learns the habit of  
appealing  directly to ,nature1 and of  
acquiring through his senses concrete   
images  of those properties of things1  
which are1 and always will be1 but      
approximatively expressed in human      
language4 ,our way of looking at        
,nature1 and of speaking about her1     
varies from year to year2 but a fact    
once seen1 a relation of cause and      
effect1 once demonstratively            
apprehended1 are possessions which      
neither change nor pass away1 but1 on   
the contrary1 form fixed centres1 about 
which other truths aggregate by  natural
 affinity4    ,therefore1 the great     
business of the scientific teacher is1  
to imprint  the fundamental1            

irrefragable facts of his science1 not  
only by words  upon the mind1 but by    
sensible impressions upon the eye1 and  
ear1 and  touch of the student1 in so   
complete a manner1 that every term used1
 or  law enunciated1 should afterwards  
call up vivid images of the particular  
structural1 or other1 facts which       
furnished the demonstration of the law1 
or the illustration of the term4    ,now
 this important operation can only be   
achieved by constant  demonstration1    
which may take place to a certain       
imperfect extent during  a lecture1 but 
which ought also to be carried on       
independently1 and which  should be     
addressed to each individual student1   
the teacher endeavouring1  not so much  
to show a thing to the learner1 as to   
make him see it for  himself4    ,i am  
well aware that there are great         
practical difficulties in the way of    
effectual zoological demonstrations4    
,the dissection of animals is not       
altogether pleasant1 and requires much  

time2 nor is it easy to secure an       
adequate supply of the needful          
specimens4 ,the botanist has here a     
great  advantage2 his specimens are     
easily obtained1 are clean and          
wholesome1  and can be dissected in a   
private house as well as anywhere else2 
and  hence1 ,i believe1 the fact1 that  
botany is so much more readily and      
better taught than its sister science4  
,but1 be it difficult or be it  easy1 if
 zoological science is to be properly   
studied1 demonstration1  and1           
consequently1 dissection1 must be had4  
,without it1 no man can have a  really  
sound knowledge of animal organisation4 
,a good deal may be done1 however1      
without actual dissection on the        
student's part1 by demonstration upon   
specimens and preparations2 and in  all 
probability it would not be very        
difficult1 were the demand  sufficient1 
to organise collections of such objects1
 sufficient for all  the purposes of    
elementary teaching1 at a comparatively 

cheap rate4 ,even  without these1 much  
might be effected1 if the zoological    
collections1  which are open to the     
public1 were arranged according to what 
has been  termed the typical principle2 
that is to say1 if the specimens exposed
  to public view were so selected that  
the public could learn something  from  
them1 instead of being1 as at present1  
merely confused by their  multiplicity4 
,for example1 the grand ornithological  
gallery at the  ,british ,museum        
contains between two and three thousand 
species of birds1  and sometimes five or
 six specimens of a species4 ,they are  
very pretty to  look at1 and some of the
 cases are1 indeed1 splendid2 but ,i    
will  undertake to say1 that no man but 
a professed ornithologist has ever      
gathered much information from the      
collection4 ,certainly1 no one of the   
tens of thousands of the general public 
who have walked through that  gallery   
ever knew more about the essential      
peculiarities of birds when he  left the

 gallery than when he entered it4 ,but  
if1 somewhere in that vast  hall1 there 
were a few preparations1 exemplifying   
the leading structural  peculiarities   
and the mode of development of a common 
fowl2 if the types  of the genera1 the  
leading modifications in the skeleton1  
in the plumage  at various ages1 in the 
mode of nidification1 and the like1     
among birds1  were displayed2 and if the
 other specimens were put away in a     
place where  the men of science1 to whom
 they are alone useful1 could have free 
access  to them1 ,i can conceive that   
this collection might become a great    
instrument of scientific education4     
,the last implement of the teacher to   
which ,i have adverted is               
examination--a means of education now so
 thoroughly understood that ,i  need    
hardly enlarge upon it4 ,i hold that    
both written and oral  examinations are 
indispensable1 and1 by requiring the    
description of  specimens1 they may be  
made to supplement demonstration4       

,such is the fullest reply the time at  
my disposal will allow me to give  to   
the question--how may a knowledge of    
zoology be best acquired and            
communicated8    ,but there is a        
previous question which may be moved1   
and which1 in fact1  ,i know many are   
inclined to move4 ,it is the question1  
why should teachers  be encouraged to   
acquire a knowledge of this1 or any     
other branch of  physical science8 ,what
 is the use1 it is said1 of attempting  
to make  physical science a branch of   
primary education8 ,is it not probable  
that  teachers1 in pursuing such        
studies1 will be led astray from the    
acquirement of more important but less  
attractive knowledge8 ,and1 even if     
they can learn something of science     
without prejudice to their  usefulness1 
what is the good of their attempting to 
instil that knowledge  into boys whose  
real business is the acquisition of     
reading1 writing1 and  arithmetic8      
,these questions are1 and will be1 very 

commonly asked1 for they arise  from    
that profound ignorance of the value and
 true position of physical  science1    
which infests the minds of the most     
highly educated and  intelligent classes
 of the community4 ,but if ,i did not   
feel well assured  that they are capable
 of being easily and satisfactorily     
answered2 that  they have been answered 
over and over again2 and that the time  
will come  when men of liberal education
 will blush to raise such questions--,i 
should be ashamed of my position here   
to-night4 ,without doubt1 it is your    
great and very important function to    
carry out elementary education2  without
 question1 anything that should         
interfere with the faithful  fulfilment 
of that duty on your part would be a    
great evil2 and if ,i  thought that your
 acquirement of the elements of physical
 science1 and  your communication of    
those elements to your pupils1 involved 
any sort of  interference with your     
proper duties1 ,i should be the first   

person to  protest against your being   
encouraged to do anything of the kind4  
,but is it true that the acquisition of 
such a knowledge of science as is       
proposed1 and the communication of that 
knowledge1 are calculated to  weaken    
your usefulness8 ,or may ,i not rather  
ask1 is it possible for you  to         
discharge your functions properly       
without these aids8    ,what is the     
purpose of primary intellectual         
education8 ,i apprehend that  its first 
object is to train the young in the use 
of those tools  wherewith men extract   
knowledge from the ever-shifting        
succession of  phenomena which pass     
before their eyes2 and that its second  
object is to  inform them of the        
fundamental laws which have been found  
by experience  to govern the course of  
things1 so that they may not be turned  
out into  the world naked1 defenceless1 
and a prey to the events they might     
control4    ,a boy is taught to read his
 own and other languages1 in order that 

he may  have access to infinitely wider 
stores of knowledge than could ever be  
opened to him by oral intercourse with  
his fellow men2 he learns to  write1    
that his means of communication with the
 rest of mankind may be  indefinitely   
enlarged1 and that he may record and    
store up the knowledge  he acquires4 ,he
 is taught elementary mathematics1 that 
he may understand  all those relations  
of number and form1 upon which the      
transactions of  men1 associated in     
complicated societies1 are built1 and   
that he may have  some practice in      
deductive reasoning4    ,all these      
operations of reading1 writing1 and     
ciphering1 are intellectual  tools1     
whose use should1 before all things1 be 
learned1 and learned  thoroughly2 so    
that the youth may be enabled to make   
his life that which  it ought to be1 a  
continual progress in learning and in   
wisdom4    ,but1 in addition1 primary   
education endeavours to fit a boy out   
with a  certain equipment of positive   

knowledge4 ,he is taught the great laws 
of  morality2 the religion of his sect2 
so much history and geography as will   
tell him where the great countries of   
the world are1 what they are1 and  how  
they have become what they are4         
,without doubt all these are most       
fitting and excellent things to teach a 
boy2 ,i should be very sorry to omit any
 of them from any scheme of  primary    
intellectual education4 ,the system is  
excellent1 so far as it  goes4    ,but  
if ,i regard it closely1 a curious      
reflection arises4 ,i suppose that1     
fifteen hundred years ago1 the child of 
any well-to-do ,roman citizen was       
taught just these same things2 reading  
and writing in his own1 and1  perhaps1  
the ,greek tongue2 the elements of      
mathematics2 and the religion1          
morality1 history1 and geography current
 in his time4 ,furthermore1 ,i do  not  
think ,i err in affirming1 that1 if such
 a ,christian ,roman boy1 who  had      
finished his education1 could be        

transplanted into one of our public     
schools1 and pass through its course of 
instruction1 he would not meet  with a  
single unfamiliar line of thought2      
amidst all the new facts he  would have 
to learn1 not one would suggest a       
different mode of regarding  the        
universe from that current in his own   
time4    ,and yet surely there is some  
great difference between the            
civilisation of  the fourth century and 
that of the nineteenth1 and still more  
between the  intellectual habits and    
tone of thought of that day and this8   
,and what has made this difference8 ,i  
answer fearlessly--,the prodigious      
development of physical science within  
the last two centuries4    ,modern      
civilisation rests upon physical        
science2 take away her gifts to  our own
 country1 and our position among the    
leading nations of the world  is gone   
to-morrow2 for it is physical science   
only that makes  intelligence and moral 
energy stronger than brute force4       

,the whole of modern thought is steeped 
in science2 it has made its way  into   
the works of our best poets1 and even   
the mere man of letters1 who  affects to
 ignore and despise science1 is         
unconsciously impregnated with  her     
spirit1 and indebted for his best       
products to her methods4 ,i believe     
that the greatest intellectual          
revolution mankind has yet seen is now  
slowly taking place by her agency4 ,she 
is teaching the world that the  ultimate
 court of appeal is observation and     
experiment1 and not  authority2 she is  
teaching it to estimate the value of    
evidence2 she is  creating a firm and   
living faith in the existence of        
immutable moral and  physical laws1     
perfect obedience to which is the       
highest possible aim of  an intelligent 
being4    ,but of all this your old     
stereotyped system of education takes no
 note4  ,physical science1 its methods1 
its problems1 and its difficulties1 will
  meet the poorest boy at every turn1   

and yet we educate him in such a  manner
 that he shall enter the world as       
ignorant of the existence of the        
methods and facts of science as the day 
he was born4 ,the modern world is  full 
of artillery2 and we turn out our       
children to do battle in it1  equipped  
with the shield and sword of an ancient 
gladiator4    ,posterity will cry shame 
on us if we do not remedy this          
deplorable state  of things4 ,nay1 if we
 live twenty years longer1 our own      
consciences will  cry shame on us4      
,it is my firm conviction that the only 
way to remedy it is to make the         
elements of physical science an integral
 part of primary education4 ,i  have    
endeavoured to show you how that may be 
done for that branch of  science which  
it is my business to pursue2 and ,i can 
but add1 that ,i  should look upon the  
day when every schoolmaster throughout  
this land was  a centre of genuine1     
however rudimentary1 scientific         
knowledge1 as an  epoch in the history  

of the country4    ,but let me entreat  
you to remember my last words4          
,addressing myself to  you1 as teachers1
 ,i would say1 mere book learning in    
physical science is  a sham and a       
delusion--what you teach1 unless you    
wish to be impostors1  that you must    
first know2 and real knowledge in       
science means personal  acquaintance    
with the facts1 be they few or many4#b  
,footnote #b3 ,it has been suggested to 
me that these words may be taken to     
imply a discouragement on my part of any
 sort of scientific instruction  which  
does not give an acquaintance with the  
facts at first hand4 ,but  this is not  
my meaning4 ,the ideal of scientific    
teaching is1 no doubt1 a  system by     
which the scholar sees every fact for   
himself1 and the teacher  supplies only 
the explanations4 ,circumstances1       
however1 do not often  allow of the     
attainment of that ideal1 and we must   
put up with the next  best system--one  
in which the scholar takes a good deal  

on trust from a  teacher1 who1 knowing  
the facts by his own knowledge1 can     
describe them  with so much vividness as
 to enable his audience to form         
competent ideas  concerning them4 ,the  
system which ,i repudiate is that which 
allows  teachers who have not come into 
direct contact with the leading facts of
  a science to pass their second-hand   
information on4 ,the scientific virus1  
like vaccine lymph1 if passed through   
too long a succession of organisms1     
will lose all its effect in protecting  
the young against the intellectual      
epidemics to which they are exposed4    
,the remarks on p4 #bbb applied to the  
,natural ,history ,collection of the    
,british ,museum in #ahfa4 ,the visitor 
to the ,natural ,history ,museum in     
#ahid  need go no further than the      
,great ,hall to see the realisation of  
my hopes  by the present ,director4     
,,viii      ,,biogenesis ,,and          
,,abiogenesis    7,,the ,,presidential  
,,address ,,to ,,the ,,british          

,,association ,,for ,,the ,,advancement 
,,of ,,science ,,for #ahgj7    ,it has  
long been the custom for the newly      
installed ,president of the  ,british   
,association for the ,advancement of    
,science to take advantage of  the      
elevation of the position in which the  
suffrages of his colleagues  had1 for   
the time1 placed him1 and1 casting his  
eyes around the horizon  of the         
scientific world1 to report to them what
 could be seen from his  watch-tower2 in
 what directions the multitudinous      
divisions of the noble  army of the     
improvers of natural knowledge were     
marching2 what important  strongholds of
 the great enemy of us all1 ignorance1  
had been recently  captured2 and1 also1 
with due impartiality1 to mark where the
 advanced  posts of science had been    
driven in1 or a long-continued siege had
 made  no progress4    ,i propose to    
endeavour to follow this ancient        
precedent1 in a manner  suited to the   
limitations of my knowledge and of my   

capacity4 ,i shall not  presume to      
attempt a panoramic survey of the world 
of science1 nor even  to give a sketch  
of what is doing in the one great       
province of biology1  with some portions
 of which my ordinary occupations render
 me familiar4  ,but ,i shall endeavour  
to put before you the history of the    
rise and  progress of a single          
biological doctrine2 and ,i shall try to
 give some  notion of the fruits1 both  
intellectual and practical1 which we    
owe1  directly or indirectly1 to the    
working out1 by seven generations of    
patient and laborious investigators1 of 
the thought which arose1 more  than two 
centuries ago1 in the mind of a         
sagacious and observant ,italian        
naturalist4    ,it is a matter of       
everyday experience that it is difficult
 to prevent  many articles of food from 
becoming covered with mould2 that fruit1
 sound  enough to all appearance1 often 
contains grubs at the core2 that meat1  
left to itself in the air1 is apt to    

putrefy and swarm with maggots4 ,even   
ordinary water1 if allowed to stand in  
an open vessel1 sooner or later  becomes
 turbid and full of living matter4      
,the philosophers of antiquity1         
interrogated as to the cause of these   
phenomena1 were provided with a ready   
and a plausible answer4 ,it did not     
enter their minds even to doubt that    
these low forms of life were  generated 
in the matters in which they made their 
appearance4 ,lucretius1  who had drunk  
deeper of the scientific spirit than any
 poet of ancient or  modern times except
 ,goethe1 intends to speak as a         
philosopher1 rather  than as a poet1    
when he writes that with good reason the
 earth has  gotten the name of mother1  
since all things are produced out of the
  earth4 ,and many living creatures1    
even now1 spring out of the earth1      
taking form by the rains and the heat of
 the sun4#a ,the axiom of  ancient      
science1 that the corruption of one     
thing is the birth of  another1 had its 

popular embodiment in the notion that a 
seed dies  before the young plant       
springs from it2 a belief so widespread 
and so  fixed1 that ,saint ,paul appeals
 to it in one of the most splendid      
outbursts of his fervid eloquence3--    
,thou fool1 that which thou sowest is   
not quickened1 except it die4#b         
,footnote #a3 ,it is thus that ,mr4     
,munro renders    ,linquitur1 ut merito 
maternum nomen adepta  ,terra sit1 e    
terra quoniam sunt cuncta creata4       
,multaque nunc etiam exsistant animalia 
terris  ,imbribus et calido solis       
concreta vapore4    ,de ,rerum ,natura1 
lib4 v4 #gic-gif4    ,but would not the 
meaning of the last line be better      
rendered ,developed  in rain-water and  
in the warm vapours raised by the sun8  
,footnote #b3 #a ,corinthians xv4 #cf4  
,the proposition that life may1 and     
does1 proceed from that which has no    
life1 then1 was held alike by the       
philosophers1 the poets1 and the        
people1 of the most enlightened nations1

 eighteen hundred years ago2 and  it    
remained the accepted doctrine of       
learned and unlearned ,europe1  through 
the ,middle ,ages1 down even to the     
seventeenth century4    ,it is commonly 
counted among the many merits of our    
great countryman1  ,harvey1 that he was 
the first to declare the opposition of  
fact to  venerable authority in this1 as
 in other matters2 but ,i can discover  
no  justification for this widespread   
notion4 ,after careful search through   
the ,exercitationes de ,generatione1 the
 most that appears clear to me  is1 that
 ,harvey believed all animals and plants
 to spring from what he  terms a        
primordium vegetale1 a phrase which may 
nowadays be rendered  a vegetative germ2
 and this1 he says1 is oviforme1 or     
egg-like2  not1 he is careful to add1   
that it necessarily has the shape of an 
egg1  but because it has the            
constitution and nature of one4 ,that   
this  primordium oviforme must needs1 in
 all cases1 proceed from a living       

parent is nowhere expressly maintained  
by ,harvey1 though such an opinion  may 
be thought to be implied in one or two  
passages2 while1 on the other  hand1 he 
does1 more than once1 use language which
 is consistent only with  a full belief 
in spontaneous or equivocal             
generation4#c ,in fact1 the  main       
concern of ,harvey's wonderful little   
treatise is not with  generation1 in the
 physiological sense1 at all1 but with  
development2 and  his great object is   
the establishment of the doctrine of    
epigenesis4    ,footnote #c3 ,see the   
following passage in ,exercitatio       
,i43--,item sponte  nascentia dicuntur2 
non quod ex putredine oriunda sint1 sed 
quod casu1  naturae sponte1 et aequivoc 
7ut aiunt7 generatione1 a parentibus sui
  dissimilibus proveniant4 ,again1 in   
,de ,uteri ,membranis3--,in cunctorum   
viventium generatione 7sicut diximus7   
hoc solenne est1 ut ortum ducunt a      
primordio aliquo1 quod tum materiam tum 
elficiendi potestatem in se  habet3     

sitque1 adeo id1 ex quo et a quo        
quicquid nascitur1 ortum suum  ducat4   
,tale primordium in animalibus 7sive ab 
aliis generantibus  proveniant1 sive    
sponte1 aut ex putredine nascentur7 est 
humor in  tunic1 aliquaut putami ne     
conclusus4 ,compare also what ,redi has 
to say  respecting ,harvey's opinions1  
,esperienze1 p4 #aa4    ,the first      
distinct enunciation of the hypothesis  
that all living matter  has sprung from 
pre-existing living matter1 came from a 
contemporary1  though a junior1 of      
,harvey1 a native of that country1      
fertile in men  great in all departments
 of human activity1 which was to        
intellectual  ,europe1 in the sixteenth 
and seventeenth centuries1 what ,germany
 is in  the nineteenth4 ,it was in      
,italy1 and from ,italian teachers1 that
 ,harvey  received the most important   
part of his scientific education4 ,and  
it was  a student trained in the same   
schools1 ,francesco ,redi--a man of the 
widest knowledge and most versatile     

abilities1 distinguished alike as       
scholar1 poet1 physician1 and           
naturalist--who1 just two hundred and   
two  years ago1 published his           
,esperienze intorno alla ,generazione   
degl'  ,insetti1 and gave to the world  
the idea1 the growth of which it is my  
purpose to trace4 ,redi's book went     
through five editions in twenty years2  
and the extreme simplicity of his       
experiments1 and the clearness of his   
arguments1 gained for his views1 and for
 their consequences1 almost  universal  
acceptance4    ,redi did not trouble    
himself much with speculative           
considerations1 but  attacked particular
 cases of what was supposed to be       
spontaneous  generation experimentally4 
,here are dead animals1 or pieces of    
meat1  says he2 ,i expose them to the   
air in hot weather1 and in a few days   
they  swarm with maggots4 ,you tell me  
that these are generated in the dead    
flesh2 but if ,i put similar bodies1    
while quite fresh1 into a jar1 and  tie 

some fine gauze over the top of the jar1
 not a maggot makes its  appearance1    
while the dead substances1 nevertheless1
 putrefy just in the  same way as       
before4 ,it is obvious1 therefore1 that 
the maggots are not  generated by the   
corruption of the meat2 and that the    
cause of their  formation must be a     
something which is kept away by gauze4  
,but gauze will  not keep away ariform  
bodies1 or fluids4 ,this something must1
 therefore1  exist in the form of solid 
particles too big to get through the    
gauze4  ,nor is one long left in doubt  
what these solid particles are2 for the 
blowflies1 attracted by the odour of the
 meat1 swarm round the vessel1  and1    
urged by a powerful but in this case    
misleading instinct1 lay eggs  out of   
which maggots are immediately hatched1  
upon the gauze4 ,the  conclusion1       
therefore1 is unavoidable2 the maggots  
are not generated by  the meat1 but the 
eggs which give rise to them are brought
 through the  air by the flies4         

,these experiments seem almost          
childishly simple1 and one wonders how  
it  was that no one ever thought of them
 before4 ,simple as they are1 however1  
they are worthy of the most careful     
study1 for every piece of  experimental 
work since done1 in regard to this      
subject1 has been shaped  upon the model
 furnished by the ,italian philosopher4 
,as the results of  his experiments were
 the same1 however varied the nature of 
the materials  he used1 it is not       
wonderful that there arose in ,redi's   
mind a  presumption1 that1 in all such  
cases of the seeming production of life 
from dead matter1 the real explanation  
was the introduction of living  germs   
from without into that dead matter4#d   
,and thus the hypothesis that  living   
matter always arises by the agency of   
pre-existing living matter1  took       
definite shape2 and had1 henceforward1 a
 right to be considered and  a claim to 
be refuted1 in each particular case1    
before the production of  living matter 

in any other way could be admitted by   
careful reasoners4 ,it  will be         
necessary for me to refer to this       
hypothesis so frequently1 that1  to save
 circumlocution1 ,i shall call it the   
hypothesis of ,biogenesis2  and ,i shall
 term the contrary doctrine--that living
 matter may be  produced by not living  
matter--the hypothesis of ,abiogenesis4 
,footnote #d3 ,pure contentandomi sempre
 in questa ed in ciascuna altro  cosa1  
da ciascuno pi savio1 l dove io         
difettuosamente parlassi1 esser         
corretto2 non tacero1 che per molte     
osservazioni molti volti da me fatte1   
mi sento inclinato a credere che la     
terra1 da quelle prime piante1 e da     
quei primi animali in poi1 che ella nei 
primi giorni del mondo produsse  per    
comandemento del sovrano ed omnipotente 
,fattore1 non abbia mai pi  prodotto da 
se medesima n erba n albero1 n animale  
alcuno perfetto o  imperfetto che ei se 
fosse2 e che tutto quello1 che ne' tempi
 trapassati   nato e che ora nascere in 

lei1 o da lei veggiamo1 venga tutto     
dalla  semenza reale e vera delle       
piante1 e degli animali stessi1 i quali 
col  mezzo del proprio seme la loro     
spezie conservano4 ,e se bene tutto     
giorno  scorghiamo da' cadaveri degli   
animali1 e da tutte quante le maniere   
dell'  erbe1 e de' fiori1 e dei frutti  
imputriditi1 e corrotti nascere vermi   
infiniti--    ',nonne vides quaecunque  
mora1 fluidoque calore  ,corpora        
tabescunt in parva animalia verti'--    
,io mi sento1 dico1 inclinato1 a credere
 che tutti quei vermi si generino  dal  
seme paterno2 e che le carni1 e l' erbe1
 e l' altre cose tutte  putrefatte1 o   
putrefattibili non facciano altra parte1
 n abbiano altro  ufizio nella          
generazione degl' insetti1 se non       
d'apprestare un luogo o un  nido        
proporzionato1 in cui dagli animali nel 
tempo della figliatura sieno  portati1 e
 partoriti i vermi1 o l' uova o l' altre
 semenze dei vermi1 i  quali tosto che  
nati sono1 trovano in esso nido un      

sufficiente alimento  abilissimo per    
nutricarsi3 e se in quello non son      
portate dalle madri  queste suddette    
semenze1 niente mai1 e replicatamente   
niente1 vi s'  ingegneri e              
nasca4--,,redi1 ,esperienze1 pp4 #ad-af4
    ,in the seventeenth century1 as ,i  
have said1 the latter was the dominant  
view1 sanctioned alike by antiquity and 
by authority2 and it is  interesting to 
observe that ,redi did not escape the   
customary tax upon a  discoverer of     
having to defend himself against the    
charge of impugning  the authority of   
the ,scriptures2#e for his adversaries  
declared that the  generation of bees   
from the carcase of a dead lion is      
affirmed1 in the  ,book of ,judges1 to  
have been the origin of the famous      
riddle with which  ,samson perplexed the
 ,philistines3--    ,out of the eater   
came forth meat1  ,and out of the strong
 came forth sweetness4    ,footnote #e3 
,molti1 e molti altri ancora vi potrei  
annoverare1 se non  fossi chiamato a    

rispondere alle rampogne di alcuni1 che 
bruscamente mi  rammentano ci1 che si   
legge nel capitolo quattordicesimo del  
sacrosanto  ,libro de' giudici 444      
--,,redi1 loc4 cit4 p4 #de4    ,against 
all odds1 however1 ,redi1 strong with   
the strength of demonstrable  fact1 did 
splendid battle for ,biogenesis2 but it 
is remarkable that he  held the doctrine
 in a sense which1 if he lead lived in  
these times1  would have infallibly     
caused him to be classed among the      
defenders of  spontaneous generation4   
,omne vivum ex vivo1 no life without    
antecedent life1 aphoristically sums up 
,redi's doctrine2 but he went no        
further4 ,it is most remarkable evidence
 of the philosophic caution and         
impartiality of his mind1 that although 
he had speculatively anticipated  the   
manner in which grubs really are        
deposited in fruits and in the galls  of
 plants1 he deliberately admits that the
 evidence is insufficient to  bear him  
out2 and he therefore prefers the       

supposition that they are  generated by 
a modification of the living substance  
of the plants  themselves4 ,indeed1 he  
regards these vegetable growths as      
organs1 by  means of which the plant    
gives rise to an animal1 and looks upon 
this  production of specific animals as 
the final cause of the galls and of1 at 
any rate1 some fruits4 ,and he proposes 
to explain the occurrence of  parasites 
within the animal body in the same      
way4#f    ,footnote #f3 ,the passage    
7,esperienze1 p4 #abi7 is worth quoting 
in  full3--    ,se dovessi palesarvi il 
mio sentimento crederei che i frutti1 i 
legumi1  gli alberi e le foglie1 in due 
maniere inverminassero4 ,una1 perch     
venendo i bachi per d fuora1 e cercando 
l' alimento1 col rodere ci  aprono la   
strada1 ed arrivano alla pi interna     
midolla de' frutti e de'  legni4        
,l'altra maniera si 1 che io per me     
stimerei1 che non fosse gran  fatto     
disdicevole il credere1 che quell' anima
 o quella virt1 la quale  genera i fiori

 ed i frutti nelle piante viventi1 sia  
quella stessa che  generi ancora i bachi
 di esse piante4 ,e chi s1 forse1 che   
molti frutti  degli alberi non sieno    
prodotti1 non per un fine primario e    
principale1  ma bensi per un uffizio    
secondario e servile1 destinato alla    
generazione  di que' vermi1 servendo a  
loro in vece di matrice1 in cui dimorino
 un  prefisso e determinato tempo2 il   
quale arrivato escan fuora a godere il  
sole4    ,io m' immagino1 che questo mio
 pensiero non vi parr totalmento un     
paradosso2 mentro farete riflessione a  
quelle tanto sorte di galle1 di         
gallozzole1 di coccole1 di ricci1 di    
calici1 di cornetti ed i lappole1  che  
son produtte dalle quercel1 dalle       
farnie1 da' cerri1 da' sugheri1 da'     
leeci e da altri simili alberi de       
ghianda2 imperciocch in quello          
gallozzole1 e particolarmente nelle pi  
grosse1 che si chiamano coronati1  ne'  
ricci capelluti1 che ciuffoli da' nostri
 contadini son detti2 nei  ricci legnosi

 del cerro1 ne' ricci stellati della    
quercia1 nelle galluzze  della foglia   
del leccio si vede evidentissimamente1  
che la prima e  principale intenzione   
della natura  formare dentro di quelle  
un animale  volante2 vedendosi nel      
centro della gallozzola un uovo1 che col
 crescere  e col maturarsi di essa      
gallozzola va crescendo e maturando     
anch' egli1 e  cresce altresi a suo     
tempo quel verme1 che nell' uovo si     
racchiude2 il  qual verme1 quando la    
gallozzola  finita di maturare e che    
venuto il  termine destinato al suo     
nascimento1 diventa1 di verme che era1  
una  mosca4444 ,io vi confesso          
ingenuamente1 che prima d'aver fatte    
queste mie  esperienze intorno alla     
generazione degl' insetti mi dava a     
credere1 o  per dir meglio sospettava1  
che forse la gallozzola nascesse1 perch 
arrivando la mosca nel tempo della      
primavera1 e facendo una piccolissima   
fessura ne' rami pi teneri della        
quercia1 in quella fessura nascondesse  

uno de suoi semi1 il quale fosse cagione
 che sbocciasse fuora la  gallozzola2 e 
che mai non si vedessero galle o        
gallozzole o ricci o  cornetti o calici 
o coccole1 se non in que' rami1 ne'     
quali le mosche  avessero depositate le 
loro semenze2 e mi dava ad intendere1   
che le  gallozzole fossero una malattia 
cagionata nelle querce dalle punture    
delle mosche1 in quella giusa stessa che
 dalle punture d'altri animaletti       
simiglievoli veggiamo crescere de'      
tumori ne' corpi degli animali4    ,it  
is of great importance to apprehend     
,redi's position rightly2 for the  lines
 of thought he laid down for us are     
those upon which naturalists  have been 
working ever since4 ,clearly1 he held   
,biogenesis as against  ,abiogenesis2   
and ,i shall immediately proceed1 in the
 first place1 to  inquire how far       
subsequent investigation has borne him  
out in so doing4    ,but ,redi also     
thought that there were two modes of    
,biogenesis4 ,by the one  method1 which 

is that of common and ordinary          
occurrence1 the living  parent gives    
rise to offspring which passes through  
the same cycle of  changes as           
itself--like gives rise to like2 and    
this has been termed  ,homogenesis4 ,by 
the other mode1 the living parent was   
supposed to give  rise to offspring     
which passed through a totally different
 series of  states from those exhibited 
by the parent1 and did not return into  
the  cycle of the parent2 this is what  
ought to be called ,heterogenesis1 the  
offspring being altogether1 and         
permanently1 unlike the parent4 ,the    
term  ,heterogenesis1 however1 has      
unfortunately been used in a different  
sense1  and ,m4 ,milne-,edwards has     
therefore substituted for it            
,xenogenesis1  which means the          
generation of something foreign4 ,after 
discussing ,redi's  hypothesis of       
universal ,biogenesis1 then1 ,i shall go
 on to ask how far  the growth of       
science justifies his other hypothesis  

of ,xenogenesis4    ,the progress of the
 hypothesis of ,biogenesis was          
triumphant and unchecked  for nearly a  
century4 ,the application of the        
microscope to anatomy in the  hands of  
,grew1 ,leeuwenhoek1 ,swammerdam1       
,lyonnet1 ,vallisnieri1 ,raurnur1  and  
other illustrious investigators of      
nature of that day1 displayed such  a   
complexity of organisation in the lowest
 and minutest forms1 and  everywhere    
revealed such a prodigality of provision
 for their  multiplication by germs of  
one sort or another1 that the hypothesis
 of  ,abiogenesis began to appear not   
only untrue1 but absurd2 and1 in the    
middle of the eighteenth century1 when  
,needham and ,buffon took up the        
question1 it was almost universally     
discredited4#g    ,footnote #g3         
,needham1 writing in #agej1 says3--     
,les naturalistes modernes s'accordent  
unaninement  tablir1 comme une  vrit    
certaine1 que toute plante vient do sa  
smence spcifique1 tout  animal d'un oeuf

 ou de quelque chose d'analogue         
prexistant dans la  plante1 ou dans     
l'animal de mme espce qui l'a           
produit4--,nouvelles  ,observations1 p4 
#afi4    ,les naturalistes out          
gnralemente cru que les animaux         
microscopiques  taient engendrs par des 
oeufs transports dans l'air1 ou dposs   
dans  des eaux dormantes par des        
insectes volans4--,ibid4 p4 #agf4       
,but the skill of the microscope makers 
of the eighteenth century soon  reached 
its limit4 ,a microscope magnifying #djj
 diameters was a chef  d'oeuvre of the  
opticians of that day2 and1 at the same 
time1 by no  means trustworthy4 ,but a  
magnifying power of #djj diameters1 even
 when  definition reaches the exquisite 
perfection of our modern achromatic     
lenses1 hardly suffices for the mere    
discernment of the smallest forms of    
life4 ,a speck1 only #a_/beth of an inch
 in diameter1 has1 at ten inches  from  
the eye1 the same apparent size as an   
object #a_/ajjjjth of an inch in        

diameter1 when magnified #djj times2 but
 forms of living matter abound1  the    
diameter of which is not more than      
#a_/djjjjth of an inch4 ,a filtered     
infusion of hay1 allowed to stand for   
two days1 will swarm with living  things
 among which1 any which reaches the     
diameter of a human red blood-          
corpuscle1 or about #a_/cbjjth of an    
inch1 is a giant4 ,it is only by        
bearing these facts in mind1 that we can
 deal fairly with the remarkable        
statements and speculations put forward 
by ,buffon and ,needham in the  middle  
of the eighteenth century4    ,when a   
portion of any animal or vegetable body 
is infused in water1 it  gradually      
softens and disintegrates2 and1 as it   
does so1 the water is  found to swarm   
with minute active creatures1 the       
so-called ,infusorial  ,animalcules1    
none of which can be seen1 except by the
 aid of the  microscope2 while a large  
proportion belong to the category of    
smallest  things of which ,i have       

spoken1 and which must have looked like 
mere dots  and lines under the ordinary 
microscopes of the eighteenth century4  
,led by various theoretical             
considerations which ,i cannot now      
discuss1 but  which looked promising    
enough in the lights of their time1     
,buffon and  ,needham doubted the       
applicability of ,redi's hypothesis to  
the infusorial  animalcules1 and        
,needham very properly endeavoured to   
put the question to  an experimental    
test4 ,he said to himself1 ,if these    
infusorial animalcules  come from germs1
 their germs must exist either in the   
substance infused1  or in the water with
 which the infusion is made1 or in the  
superjacent  air4 ,now the vitality of  
all germs is destroyed by heat4         
,therefore1 if ,i  boil the infusion1   
cork it up carefully1 cementing the cork
 over with  mastic1 and then heat the   
whole vessel by heaping hot ashes over  
it1 ,i  must needs kill whatever germs  
are present4 ,consequently1 if ,redi's  

hypothesis hold good1 when the infusion 
is taken away and allowed to  cool1 no  
animalcules ought to be developed in it2
 whereas1 if the  animalcules are not   
dependent on pre-existing germs1 but are
 generated  from the infused substance1 
they ought1 by and by1 to make their    
appearance4 ,needham found that1 under  
the circumstances in which he made  his 
experiments1 animalcules always did     
arise in the infusions1 when a          
sufficient time had elapsed to allow for
 their development4    ,in much of his  
work ,needham was associated with       
,buffon1 and the results  of their      
experiments fitted in admirably with the
 great ,french  naturalist's hypothesis 
of organic molecules1 according to      
which1 life  is the indefeasible        
property of certain indestructible      
molecules of  matter1 which exist in all
 living things1 and have inherent       
activities by  which they are           
distinguished from not living matter4   
,each individual  living organism is    

formed by their temporary combination4  
,they stand to  it in the relation of   
the particles of water to a cascade1 or 
a  whirlpool2 or to a mould1 into which 
the water is poured4 ,the form of the   
organism is thus determined by the      
reaction between external conditions    
and the inherent activities of the      
organic molecules of which it is        
composed2 and1 as the stoppage of a     
whirlpool destroys nothing but a  form1 
and leaves the molecules of the water1  
with all their inherent  activities     
intact1 so what we call the death and   
putrefaction of an  animal1 or of a     
plant1 is merely the breaking up of the 
form1 or manner  of association1 of its 
constituent organic molecules1 which are
 then set  free as infusorial           
animalcules4    ,it will be perceived   
that this doctrine is by no means       
identical with  ,abiogenesis1 with which
 it is often confounded4 ,on this       
hypothesis1 a  piece of beef1 or a      
handful of hay1 is dead only in a       

limited sense4 ,the  beef is dead ox1   
and the hay is dead grass2 but the      
organic molecules  of the beef or the   
hay are not dead1 but are ready to      
manifest their  vitality as soon as the 
bovine or herbaceous shrouds in which   
they are  imprisoned are rent by the    
macerating action of water4 ,the        
hypothesis  therefore must be classified
 under ,xenogenesis1 rather than under  
,abiogenesis4 ,such as it was1 ,i think 
it will appear1 to those who will be    
just enough to remember that it was     
propounded before the birth of modern   
chemistry1 and of the modern optical    
arts1 to be a most ingenious and        
suggestive speculation4    ,but the     
great tragedy of ,science--the slaying  
of a beautiful hypothesis  by an ugly   
fact--which is so constantly being      
enacted under the eyes of  philosophers1
 was played1 almost immediately1 for the
 benefit of ,buffon  and ,needham4      
,once more1 an ,italian1 the ,abb       
,spallanzani1 a worthy successor and    

representative of ,redi in his          
acuteness1 his ingenuity1 and his       
learning1  subjected the experiments and
 the conclusions of ,needham to a       
searching  criticism4 ,it might be true 
that ,needham's experiments yielded     
results  such as he had described1 but  
did they bear out his arguments8 ,was it
 not  possible1 in the first place1 he  
had not completely excluded the air by  
his corks and mastic8 ,and was it not   
possible1 in the second place1 that  he 
had not sufficiently heated his         
infusions and the superjacent air8      
,spallanzani joined issue with the      
,english naturalist on both these pleas1
  and he showed that if1 in the first   
place1 the glass vessels in which the   
infusions were contained were           
hermetically sealed by fusing their     
necks1  and if1 in the second place1    
they were exposed to the temperature of 
boiling water for three-quarters of an  
hour1#h no animalcules ever made  their 
appearance within them4 ,it must be     

admitted that the experiments  and      
arguments of ,spallanzani furnish a     
complete and a crushing reply to  those 
of ,needham4 ,but we all too often      
forget that it is one thing to  refute a
 proposition1 and another to prove the  
truth of a doctrine which1  implicitly  
or explicitly1 contradicts that         
proposition2 and the advance  of science
 soon showed that though ,needham might 
be quite wrong1 it did  not follow that 
,spallanzani was quite right4           
,footnote #h3 ,see ,spallanzani1 ,opere1
 vi4 pp4 #db and #ea4    ,modern        
,chemistry1 the birth of the latter half
 of the eighteenth century1  grew apace1
 and soon found herself face to face    
with the great problems  which biology  
had vainly tried to attack without her  
help4 ,the discovery  of oxygen led to  
the laying of the foundations of a      
scientific theory of  respiration1 and  
to an examination of the marvellous     
interactions of  organic substances with
 oxygen4 ,the presence of free oxygen   

appeared to  be one of the conditions of
 the existence of life1 and of those    
singular  changes in organic matters    
which are known as fermentation and     
putrefaction4 ,the question of the      
generation of the infusory animalcules  
thus passed into a new phase4 ,for what 
might not have happened to the  organic 
matter of the infusions1 or to the      
oxygen of the air1 in  ,spallanzani's   
experiments8 ,what security was there   
that the development  of life which     
ought to have taken place had not been  
checked or prevented  by these changes8 
,the battle had to be fought again4 ,it 
was needful to repeat the  experiments  
under conditions which would make sure  
that neither the  oxygen of the air1 nor
 the composition of the organic matter1 
was altered  in such a manner as to     
interfere with the existence of life4   
,schulze and ,schwann took up the       
question from this point of view in     
#ahcf  and #ahcg4 ,the passage of air   
through red-hot glass tubes1 or through 

strong sulphuric acid1 does not alter   
the proportion of its oxygen1 while  it 
must needs arrest1 or destroy1 any      
organic matter which may be  contained  
in the air4 ,these experimenters1       
therefore1 contrived  arrangements by   
which the only air which should come    
into contact with a  boiled infusion    
should be such as had either passed     
through red-hot tubes  or through strong
 sulphuric acid4 ,the result which they 
obtained was that  an infusion so       
treated developed no living things1     
while1 if the same  infusion was        
afterwards exposed to the air1 such     
things appeared rapidly  and abundantly4
 ,the accuracy of these experiments has 
been alternately  denied and affirmed4  
,supposing then1 to be accepted1        
however1 all that  they really proved   
was that the treatment to which the air 
was subjected  destroyed something that 
was essential to the development of life
 in  the infusion4 ,this something might
 be gaseous1 fluid1 or solid2 that it   

consisted of germs remained only an     
hypothesis of greater or less           
probability4    ,contemporaneously with 
these investigations a remarkable       
discovery was  made by ,cagniard de la  
,tour4 ,he found that common yeast is   
composed of a  vast accumulation of     
minute plants4 ,the fermentation of     
must1 or of wort1  in the fabrication of
 wine and of beer1 is always accompanied
 by the  rapid growth and multiplication
 of these ,toruloe4 ,thus1 fermentation1
  in so far as it was accompanied by the
 development of microscopical  organisms
 in enormous numbers1 became assimilated
 to the decomposition of  an infusion of
 ordinary animal or vegetable matter2   
and it was an obvious  suggestion that  
the organisms were1 in some way or      
other1 the causes both  of fermentation 
and of putrefaction4 ,the chemists1 with
 ,berzelius and  ,liebig at their head1 
at first laughed this idea to scorn2 but
 in #ahdc1 a  man then very young1 who  
has since performed the unexampled feat 

of  attaining to high eminence alike in 
,mathematics1 ,physics1 and             
,physiology--  ,i speak of the          
illustrious ,helmholtz--reduced the     
matter to the test of  experiment by a  
method alike elegant and conclusive4    
,helmholtz separated  a putrefying or a 
fermenting liquid from one which was    
simply putrescible  or fermentable by a 
membrane which allowed the fluids to    
pass through and  become intermixed1 but
 stopped the passage of solids4 ,the    
result was1  that while the putrescible 
or the fermentable liquids became       
impregnated  with the results of the    
putrescence or fermentation which was   
going on on  the other side of the      
membrane1 they neither putrefied 7in the
 ordinary  way7 nor fermented2 nor were 
any of the organisms which abounded in  
the  fermenting or putrefying liquid    
generated in them4 ,therefore the cause 
of  the development of these organisms  
must lie in something which cannot  pass
 through membranes2 and as ,helmholtz's 

investigations were long  antecedent to 
,graham's researches upon colloids1 his 
natural conclusion  was that the agent  
thus intercepted must be a solid        
material4 ,in point of  fact1           
,helmholtz's experiments narrowed the   
issue to this3 that which  excites      
fermentation and putrefaction1 and at   
the same time gives rise to  living     
forms in a fermentable or putrescible   
fluid1 is not a gas and is  not a       
diffusible fluid2 therefore it is either
 a colloid1 or it is matter  divided    
into very minute solid particles4       
,the researches of ,schroeder and ,dusch
 in #ahed1 and of ,schroeder alone1 in  
#ahei1 cleared up this point by         
experiments which are simply refinements
  upon those of ,redi4 ,a lump of       
cotton-wool is1 physically speaking1 a  
pile  of many thicknesses of a very fine
 gauze1 the fineness of the meshes of   
which depends upon the closeness of the 
compression of the wool4 ,now1          
,schroeder and ,dusch found1 that1 in   

the case of all the putrefiable         
materials which they used 7except milk  
and yolk of egg71 an infusion  boiled1  
and then allowed to come into contact   
with no air but such as had  been       
filtered through cotton-wool1 neither   
putrefied1 nor fermented1 nor  developed
 living forms4 ,it is hard to imagine   
what the fine sieve formed  by the      
cotton-wool could have stopped except   
minute solid particles4  ,still the     
evidence was incomplete until it had    
been positively shown1  first1 that     
ordinary air does contain such          
particles2 and1 secondly1 that          
filtration through cotton-wool arrests  
these particles and allows only         
physically pure air to pass4 ,this      
demonstration has been furnished within 
the last year by the remarkable         
experiments of ,professor ,tyndall4 ,it 
has  been a common objection of         
,abiogenists that1 if the doctrine of   
,biogeny  is true1 the air must be thick
 with germs2 and they regard this as the

  height of absurdity4 ,but nature      
occasionally is exceedingly             
unreasonable1  and ,professor ,tyndall  
has proved that this particular         
absurdity may  nevertheless be a        
reality4 ,he has demonstrated that      
ordinary air is no  better than a sort  
of stirabout of excessively minute solid
 particles2  that these particles are   
almost wholly destructible by heat2 and 
that  they are strained off1 and the air
 rendered optically pure1 by its being  
passed through cotton-wool4    ,it      
remains yet in the order of logic1      
though not of history1 to show that     
among these solid destructible          
particles1 there really do exist germs  
capable of giving rise to the           
development of living forms in suitable 
menstrua4 ,this piece of work was done  
by ,m4 ,pasteur in those beautiful      
researches which will ever render his   
name famous2 and which1 in spite of  all
 attacks upon them1 appear to me now1 as
 they did seven years ago1#i  to be     

models of accurate experimentation and  
logical reasoning4 ,he  strained air    
through cotton-wool1 and found1 as      
,schroeder and ,dusch had  done1 that it
 contained nothing competent to give    
rise to the development  of life in     
fluids highly fitted for that purpose4  
,but the important  further links in the
 chain of evidence added by ,pasteur are
 three4 ,in the  first place he         
subjected to microscopic examination the
 cotton-wool which  had served as       
strainer1 and found that sundry bodies  
clearly recognisable  as germs1 were    
among the solid particles strained off4 
,secondly1 he  proved that these germs  
were competent to give rise to living   
forms by  simply sowing them in a       
solution fitted for their development4  
,and1  thirdly1 he showed that the      
incapacity of air strained through      
cotton-  wool to give rise to life1 was 
not due to any occult change effected in
  the constituents of the air by the    
wool1 by proving that the cotton-wool   

might be dispensed with altogether1 and 
perfectly free access left  between the 
exterior air and that in the            
experimental flask4 ,if the neck  of the
 flask is drawn out into a tube and bent
 downwards2 and if1 after  the contained
 fluid has been carefully boiled1 the   
tube is heated  sufficiently to destroy 
any germs which may be present in the   
air which  enters as the fluid cools1   
the apparatus may be left to itself for 
any  time and no life will appear in the
 fluid4 ,the reason is plain4 ,although 
there is free communication between the 
atmosphere laden with germs and  the    
germless air in the flask1 contact      
between the two takes place only  in the
 tube2 and as the germs cannot fall     
upwards1 and there are no  currents1    
they never reach the interior of the    
flask4 ,but if the tube be  broken short
 off where it proceeds from the flask1  
and free access be  thus given to germs 
falling vertically out of the air1 the  
fluid1 which  has remained clear and    

desert for months1 becomes1 in a few    
days1 turbid  and full of life4         
,footnote #i3 ,lectures to ,working ,men
 on the ,causes of the ,phenomena of    
,organic ,nature1 #ahfc4 7,see ,vol4    
,,ii4 of these ,essays47    ,these      
experiments have been repeated over and 
over again by independent  observers    
with entire success2 and there is one   
very simple mode of  seeing the facts   
for one's self1 which ,i may as well    
describe4    ,prepare a solution 7much  
used by ,m4 ,pasteur1 and often called  
,pasteur's  solution7 composed of water 
with tartrate of ammonia1 sugar1 and    
yeast-  ash dissolved therein4#aj       
,divide it into three portions in as    
many  flasks2 boil all three for a      
quarter of an hour2 and1 while the steam
 is  passing out1 stop the neck of one  
with a large plug of cotton-wool1 so    
that this also may be thoroughly        
steamed4 ,now set the flasks aside to   
cool1 and1 when their contents are cold1
 add to one of the open ones a  drop of 

filtered infusion of hay which has stood
 for twenty-four hours1  and is         
consequently hill of the active and     
excessively minute organisms  known as  
,bacteria4 ,in a couple of days of      
ordinary warm weather the  contents of  
this flask will be milky from the       
enormous multiplication of  ,bacteria4  
,the other flask1 open and exposed to   
the air1 will1 sooner or  later1 become 
milky with ,bacteria1 and patches of    
mould may appear in  it2 while the      
liquid in the flask1 the neck of which  
is plugged with  cotton-wool1 will      
remain clear for an indefinite time4 ,i 
have sought in  vain for any explanation
 of these facts1 except the obvious one1
 that the  air contains germs competent 
to give rise to ,bacteria1 such as those
  with which the first solution has been
 knowingly and purposely  inoculated1   
and to the mould-,fungi4 ,and ,i have   
not yet been able to  meet with any     
advocate of ,abiogenesis who seriously  
maintains that the  atoms of sugar1     

tartrate of ammonia1 yeast-ash1 and     
water1 under no  influence but that of  
free access of air and the ordinary     
temperature1  re-arrange themselves and 
give rise to the protoplasm of          
,bacterium4 ,but  the alternative is to 
admit that these ,bacteria arise from   
germs in the  air2 and if they are thus 
propagated1 the burden of proof that    
other like  forms are generated in a    
different manner1 must rest with the    
assertor of  that proposition4          
,footnote #aj3 ,infusion of hay treated 
in the same way yields similar  results2
 but as it contains organic matter1 the 
argument which follows  cannot be based 
upon it4    ,to sum up the effect of    
this long chain of evidence3--    ,it is
 demonstrable that a fluid eminently fit
 for the development of the  lowest     
forms of life1 but which contains       
neither germs1 nor any protein          
compound1 gives rise to living things in
 great abundance if it is exposed  to   
ordinary air2 while no such development 

takes place1 if the air with  which it  
is in contact is mechanically freed from
 the solid particles  which ordinarily  
float in it1 and which may be made      
visible by  appropriate means4    ,it is
 demonstrable that the great majority of
 these particles are  destructible by   
heat1 and that some of them are germs1  
or living  particles1 capable of giving 
rise to the same forms of life as those 
which appear when the fluid is exposed  
to unpurified air4    ,it is            
demonstrable that inoculation of the    
experimental fluid with a drop  of      
liquid known to contain living particles
 gives rise to the same  phenomena as   
exposure to unpurified air4    ,and it  
is further certain that these living    
particles are so minute that  the       
assumption of their suspension in       
ordinary air presents not the  slightest
 difficulty4 ,on the contrary1          
considering their lightness and  the    
wide diffusion of the organisms which   
produce them1 it is impossible  to      

conceive that they should not be        
suspended in the atmosphere in  myriads4
    ,thus the evidence1 direct and      
indirect1 in favour of ,biogenesis for  
all  known forms of life must1 ,i think1
 be admitted to be of great weight4     
,on the other side1 the sole assertions 
worthy of attention are that            
hermetically sealed fluids1 which have  
been exposed to great and long-         
continued heat1 have sometimes exhibited
 living forms of low organisation  when 
they have been opened4    ,the first    
reply that suggests itself is the       
probability that there must  be some    
error about these experiments1 because  
they are performed on an  enormous scale
 every day with quite contrary results4 
,meat1 fruits1  vegetables1 the very    
materials of the most fermentable and   
putrescible  infusions1 are preserved to
 the extent1 ,i suppose ,i may say1 of  
thousands  of tons every year1 by a     
method which is a mere application of   
,spallanzani's experiment4 ,the matters 

to be preserved are well boiled in  a   
tin case provided with a small hole1 and
 this hole is soldered up when  all the 
air in the case has been replaced by    
steam4 ,by this method they  may be kept
 for years without putrefying1          
fermenting1 or getting mouldy4  ,now    
this is not because oxygen is excluded1 
inasmuch as it is now proved  that free 
oxygen is not necessary for either      
fermentation or  putrefaction4 ,it is   
not because the tins are exhausted of   
air1 for  ,vibriones and ,bacteria live1
 as ,pasteur has shown1 without air or  
free oxygen4 ,it is not because the     
boiled meats or vegetables are not      
putrescible or fermentable1 as those who
 have had the misfortune to be in  a    
ship supplied with unskilfully closed   
tins well know4 ,what is it1  therefore1
 but the exclusion of germs8 ,i think   
that ,abiogenists are bound  to answer  
this question before they ask us to     
consider new experiments of  precisely  
the same order4    ,and in the next     

place1 if the results of the experiments
 ,i refer to are  really trustworthy1 it
 by no means follows that ,abiogenesis  
has taken  place4 ,the resistance of    
living matter to heat is known to vary  
within  considerable limits1 and to     
depend1 to some extent1 upon the        
chemical and  physical qualities of the 
surrounding medium4 ,but if1 in the     
present  state of science1 the          
alternative is offered us1--either germs
 can stand  a greater heat than has been
 supposed1 or the molecules of dead     
matter1  for no valid or intelligible   
reason that is assigned1 are able to re-
  arrange themselves into living bodies1
 exactly such as can be  demonstrated to
 be frequently produced in another      
way1--,i cannot  understand how choice  
can be1 even for a moment1 doubtful4    
,but though ,i cannot express this      
conviction of mine too strongly1 ,i must
  carefully guard myself against the    
supposition that ,i intend to suggest   
that no such thing as ,abiogenesis ever 

has taken place in the past1 or  ever   
will take place in the future4 ,with    
organic chemistry1 molecular  physics1  
and physiology yet in their infancy1 and
 every day making  prodigious strides1  
,i think it would be the height of      
presumption for any  man to say that the
 conditions under which matter assumes  
the properties  we call vital may not1  
some day1 be artificially brought       
together4 ,all  ,i feel justified in    
affirming is1 that ,i see no reason for 
believing that  the feat has been       
performed yet4    ,and looking back     
through the prodigious vista of the     
past1 ,i find no  record of the         
commencement of life1 and therefore ,i  
am devoid of any  means of forming a    
definite conclusion as to the conditions
 of its  appearance4 ,belief1 in the    
scientific sense of the word1 is a      
serious  matter1 and needs strong       
foundations4 ,to say1 therefore1 in the 
admitted  absence of evidence1 that ,i  
have any belief as to the mode in which 

the  existing forms of life have        
originated1 would be using words in a   
wrong  sense4 ,but expectation is       
permissible where belief is not2 and if 
it were  given me to look beyond the    
abyss of geologically recorded time to  
the  still more remote period when the  
earth was passing through physical and  
chemical conditions1 which it can no    
more see again than a man can recall    
his infancy1 ,i should expect to be a   
witness of the evolution of living      
protoplasm from not living matter4 ,i   
should expect to see it appear under    
forms of great simplicity1 endowed1 like
 existing fungi1 with the power  of     
determining the formation of new        
protoplasm from such matters as         
ammonium carbonates1 oxalates and       
tartrates1 alkaline and earthy          
phosphates1 and water1 without the aid  
of light4 ,that is the expectation  to  
which analogical reasoning leads me2 but
 ,i beg you once more to  recollect that
 ,i have no right to call my opinion    

anything but an act of  philosophical   
faith4    ,so much for the history of   
the progress of ,redi's great doctrine  
of  ,biogenesis1 which appears to me1   
with the limitations ,i have expressed1 
to be victorious along the whole line at
 the present day4    ,as regards the    
second problem offered to us by ,redi1  
whether ,xenogenesis  obtains1 side by  
side with ,homogenesis1--whether1 that  
is1 there exist  not only the ordinary  
living things1 giving rise to offspring 
which run  through the same cycle as    
themselves1 but also others1 producing  
offspring which are of a totally        
different character from themselves1--  
the researches of two centuries have led
 to a different result4 ,that the  grubs
 found in galls are no product of the   
plants on which the galls  grow1 but are
 the result of the introduction of the  
eggs of insects into  the substance of  
these plants1 was made out by           
,vallisnieri1 ,raumur1 and  others1     
before the end of the first half of the 

eighteenth century4 ,the  tapeworms1    
bladderworms1 and flukes continued to be
 a stronghold of the  advocates of      
,xenogenesis for a much longer period4  
,indeed1 it is only  within the last    
thirty years that the splendid patience 
of ,von ,siebold1  ,van ,beneden1       
,leuckart1 ,kchenmeister1 and other     
helminthologists1 has  succeeded in     
tracing every such parasite1 often      
through the strangest  wanderings and   
metamorphoses1 to an egg derived from a 
parent1 actually  or potentially like   
itself2 and the tendency of inquiries   
elsewhere has  all been in the same     
direction4 ,a plant may throw off bulbs1
 but these1  sooner or later1 give rise 
to seeds or spores1 which develop into  
the  original form4 ,a polype may give  
rise to ,medusae1 or a pluteus to an    
,echinoderm1 but the ,medusa and the    
,echinoderm give rise to eggs which     
produce polypes or glutei1 and they are 
therefore only stages in the  cycle of  
life of the species4    ,but if we turn 

to pathology1 it offers us some         
remarkable approximations  to true      
,xenogenesis4    ,as ,i have already    
mentioned1 it has been known since the  
time of  ,vallisnieri and of ,raumur1   
that galls in plants1 and tumours in    
cattle1  are caused by insects1 which   
lay their eggs in those parts of the    
animal  or vegetable frame of which     
these morbid structures are outgrowths4 
,again1 it is a matter of familiar      
experience to everybody that mere       
pressure on the skin will give rise to a
 corn4 ,now the gall1 the tumour1  and  
the corn are parts of the living body1  
which have become1 to a  certain degree1
 independent and distinct organisms4    
,under the influence  of certain        
external conditions1 elements of the    
body1 which should have  developed in   
due subordination to its general plan1  
set up for themselves  and apply the    
nourishment which they receive to their 
own purposes4    ,from such innocent    
productions as corns and warts1 there   

are all  gradations to the serious      
tumours which1 by their mere size and   
the  mechanical obstruction they cause1 
destroy the organism out of which they  
are developed2 while1 finally1 in those 
terrible structures known as  cancers1  
the abnormal growth has acquired powers 
of reproduction and  multiplication1 and
 is only morphologically distinguishable
 from the  parasitic worm1 the life of  
which is neither more nor less closely  
bound  up with that of the infested     
organism4    ,if there were a kind of   
diseased structure1 the histological    
elements of  which were capable of      
maintaining a separate and independent  
existence  out of the body1 it seems to 
me that the shadowy boundary between    
morbid  growth and ,xenogenesis would be
 effaced4 ,and ,i am inclined to think  
that  the progress of discovery has     
almost brought us to this point already4
 ,i  have been favoured by ,mr4 ,simon  
with an early copy of the last published
  of the valuable ,reports on the       

,public ,health1 which1 in his capacity 
of  their medical officer1 he annually  
presents to the ,lords of the ,privy    
,council4 ,the appendix to this report  
contains an introductory essay ,on  the 
,intimate ,pathology of ,contagion1 by  
,dr4 ,burdon-,sanderson1 which is  one  
of the clearest1 most comprehensive1 and
 well-reasoned discussions of  a great  
question which has come under my notice 
for a long time4 ,i refer  you to it for
 details and for the authorities for the
 statements ,i am  about to make4       
,you are familiar with what happens in  
vaccination4 ,a minute cut is made  in  
the skin1 and an infinitesimal quantity 
of vaccine matter is inserted  into the 
wound4 ,within a certain time a vesicle 
appears in the place of  the wound1 and 
the fluid which distends this vesicle is
 vaccine matter1  in quantity a hundred 
or a thousandfold that which was        
originally  inserted4 ,now what has     
taken place in the course of this       
operation8 ,has  the vaccine matter1 by 

its irritative property1 produced a mere
 blister1  the fluid of which has the   
same irritative property8 ,or does the  
vaccine  matter contain living          
particles1 which have grown and         
multiplied where  they have been        
planted8 ,the observations of ,m4       
,chauveau1 extended and  confirmed by   
,dr4 ,sanderson himself1 appear to leave
 no doubt upon this  head4 ,experiments1
 similar in principle to those of       
,helmholtz on  fermentation and         
putrefaction1 have proved that the      
active element in the  vaccine lymph is 
non-diffusible1 and consists of minute  
particles not  exceeding #a_/bjjjjth of 
an inch in diameter1 which are made     
visible in the  lymph by the microscope4
 ,similar experiments have proved that  
two of the  most destructive of         
epizootic diseases1 sheep-pox and       
glanders1 are also  dependent for their 
existence and their propagation upon    
extremely small  living solid particles1
 to which the title of microzymes is    

applied4 ,an  animal suffering under    
either of these terrible diseases is a  
source of  infection and contagion to   
others1 for precisely the same reason as
 a tub  of fermenting beer is capable of
 propagating its fermentation by        
infection1 or contagion1 to fresh wort4 
,in both cases it is the solid  living  
particles which are efficient2 the      
liquid in which they float1 and  at the 
expense of which they live1 being       
altogether passive4    ,now arises the  
question1 are these microzymes the      
results of  ,homogenesis1 or of         
,xenogenesis8 are they capable1 like the
  ,toruloe of yeast1 of arising only by 
the development of pre-existing  germs8 
or may they be1 like the constituents of
 a nut-gall1 the results  of a          
modification and individualisation of   
the tissues of the body in  which they  
are found1 resulting from the operation 
of certain conditions8  ,are they       
parasites in the zoological sense1 or   
are they merely what  ,virchow has      

called heterologous growths8 ,it is     
obvious that this  question has the most
 profound importance1 whether we look at
 it from a  practical or from a         
theoretical point of view4 ,a parasite  
may be stamped  out by destroying its   
germs1 but a pathological product can   
only be  annihilated by removing the    
conditions which give rise to it4    ,it
 appears to me that this great problem  
will have to be solved for each  zymotic
 disease separately1 for analogy cuts   
two ways4 ,i have dwelt upon  the       
analogy of pathological modification1   
which is in favour of the  xenogenetic  
origin of microzymes2 but ,i must now   
speak of the equally  strong analogies  
in favour of the origin of such         
pestiferous particles by  the ordinary  
process of the generation of like from  
like4    ,it is1 at present1 a          
well-established fact that certain      
diseases1 both of  plants and of        
animals1 which have all the characters  
of contagious and  infectious epidemics1

 are caused by minute organisms4 ,the   
smut of wheat  is a well-known instance 
of such a disease1 and it cannot be     
doubted that  the grape-disease and the 
potato-disease fall under the same      
category4  ,among animals1 insects are  
wonderfully liable to the ravages of    
contagious and infectious diseases      
caused by microscopic ,fungi4    ,in    
autumn1 it is not uncommon to see flies 
motionless upon a window-pane1  with a  
sort of magic circle1 in white1 drawn   
round them4 ,on microscopic             
examination1 the magic circle is found  
to consist of innumerable spores1  which
 have been thrown off in all directions 
by a minute fungus called  ,empusa      
muscoe1 the spore-forming filaments of  
which stand out like a  pile of velvet  
from the body of the fly4 ,these        
spore-forming filaments  are connected  
with others which fill the interior of  
the fly's body like  so much fine wool1 
having eaten away and destroyed the     
creature's  viscera4 ,this is the       

full-grown condition of the ,empusa4 ,if
 traced back  to its earliest stages1 in
 flies which are still active1 and to   
all  appearance healthy1 it is found to 
exist in the form of minute corpuscles  
which float in the blood of the fly4    
,these multiply and lengthen into       
filaments1 at the expense of the fly's  
substance2 and when they have at  last  
killed the patient1 they grow out of its
 body and give off spores4  ,healthy    
flies shut up with diseased ones catch  
this mortal disease1 and  perish like   
the others4 ,a most competent observer1 
,m4 ,cohn1 who studied  the development 
of the ,empusa very carefully1 was      
utterly unable to  discover in what     
manner the smallest germs of the ,empusa
 got into the  fly4 ,the spores could   
not be made to give rise to such germs  
by  cultivation2 nor were such germs    
discoverable in the air1 or in the food 
of the fly4 ,it looked exceedingly like 
a case of ,abiogenesis1 or1 at any      
rate1 of ,xenogenesis2 and it is only   

quite recently that the real course  of 
events has been made out4 ,it has been  
ascertained1 that when one of  the      
spores falls upon the body of a fly1 it 
begins to germinate1 and  sends out a   
process which bores its way through the 
fly's skin2 this1  having reached the   
interior cavities of its body1 gives off
 the minute  floating corpuscles which  
are the earliest stage of the ,empusa4  
,the  disease is contagious1 because a  
healthy fly coming in contact with a    
diseased one1 from which the            
spore-bearing filaments protrude1 is    
pretty  sure to carry off a spore or    
two4 ,it is infectious because the      
spores  become scattered about all sorts
 of matter in the neighbourhood of the  
slain flies4    ,the silkworm has long  
been known to be subject to a very fatal
 and  infectious disease called the     
,muscardine4 ,audouin transmitted it by 
inoculation4 ,this disease is entirely  
due to the development of a fungus1     
,botrytis ,bassiana1 in the body of the 

caterpillar2 and its  contagiousness and
 infectiousness are accounted for in the
 same way as  those of the fly-disease4 
,but1 of late years1 a still more       
serious  epizootic has appeared among   
the silkworms2 and ,i may mention a few 
facts  which will give you some         
conception of the gravity of the injury 
which it  has inflicted on ,france      
alone4    ,the production of silk has   
been for centuries an important branch  
of  industry in ,southern ,france1 and  
in the year #ahec it had attained such a
  magnitude that the annual produce of  
the ,french sericulture was estimated   
to amount to a tenth of that of the     
whole world1 and represented a money-   
value of #aag1jjj1jjj francs1 or nearly 
five millions sterling4 ,what may  be   
the sum which would represent the       
money-value of all the industries       
connected with the working up of the raw
 silk thus produced1 is more than  ,i   
can pretend to estimate4 ,suffice it to 
say1 that the city of ,lyons is  built  

upon ,french silk as much as ,manchester
 was upon ,american cotton  before the  
civil war4    ,silkworms are liable to  
many diseases2 and1 even before #ahec1 a
 peculiar  epizootic1 frequently        
accompanied by the appearance of dark   
spots upon  the skin 7whence the name of
 ,pbrine which it has received71 had    
been  noted for its mortality4 ,but in  
the years following #ahec this malady   
broke out with such extreme violence1   
that1 in #aheh1 the silk-crop was       
reduced to a third of the amount which  
it had reached in #ahec2 and1 up  till  
within the last year or two1 it has     
never attained half the yield of  #ahec4
 ,this means not only that the great    
number of people engaged in silk        
growing are some thirty millions        
sterling poorer than they might have    
been2 it means not only that high prices
 have had to be paid for imported       
silkworm eggs1 and that1 after investing
 his money in them1 in paying for       
mulberry-leaves and for attendance1 the 

cultivator has constantly seen  his     
silkworms perish and himself plunged in 
ruin2 but it means that the  looms of   
,lyons have lacked employment1 and that1
 for years1 enforced  idleness and      
misery have been the portion of a vast  
population which1 in  former days1 was  
industrious and well-to-do4    ,in #aheh
 the gravity of the situation caused the
 ,french ,academy of  ,sciences to      
appoint ,commissioners1 of whom a       
distinguished naturalist1 ,m4  de       
,quatrefages1 was one1 to inquire into  
the nature of this disease1 and1  if    
possible1 to devise some means of       
staying the plague4 ,in reading the     
,report#aa made by ,m4 de ,quatrefages  
in #ahei1 it is exceedingly  interesting
 to observe that his elaborate study of 
the ,pbrine forced the  conviction upon 
his mind that1 in its mode of occurrence
 and propagation1  the disease of the   
silkworm is1 in every respect1          
comparable to the  cholera among        
mankind4 ,but it differs from the       

cholera1 and so far is a  more          
formidable malady1 in being hereditary1 
and in being1 under some  circumstances1
 contagious as well as infectious4      
,footnote #aa3 tudes sur les ,maladies  
actuelles des ,vers  ,soie1 p4  #ec4    
,the ,italian naturalist1 ,filippi1     
discovered in the blood of the silkworms
  affected by this strange disorder a   
multitude of cylindrical corpuscles1    
each about #a_/fjjjth of an inch long4  
,these have been carefully studied by   
,lebert1 and named by him               
,panhistophyton2 for the reason that in 
subjects in which the disease is        
strongly developed1 the corpuscles swarm
  in every tissue and organ of the body1
 and even pass into the undeveloped     
eggs of the female moth4 ,but are these 
corpuscles causes1 or mere              
concomitants1 of the disease8 ,some     
naturalists took one view and some      
another2 and it was not until the       
,french ,government1 alarmed by the     
continued ravages of the malady1 and the

 inefficiency of the remedies  which had
 been suggested1 despatched ,m4 ,pasteur
 to study it1 that the  question        
received its final settlement2 at a     
great sacrifice1 not only of  the time  
and peace of mind of that eminent       
philosopher1 but1 ,i regret to  have to 
add1 of his health4    ,but the         
sacrifice has not been in vain4 ,it is  
now certain that this  devastating1     
cholera-like1 ,pbrine1 is the effect of 
the growth and  multiplication of the   
,panhistophyton in the silkworm4 ,it is 
contagious  and infectious1 because the 
corpuscles of the ,panhistophyton pass  
away  from the bodies of the diseased   
caterpillars1 directly or indirectly1 to
  the alimentary canal of healthy       
silkworms in their neighbourhood2 it is 
hereditary because the corpuscles enter 
into the eggs while they are  being     
formed1 and consequently are carried    
within them when they are  laid2 and for
 this reason1 also1 it presents the very
 singular  peculiarity of being         

inherited only on the mother's side4    
,there is not a  single one of all the  
apparently capricious and unaccountable 
phenomena  presented by the ,pbrine1 but
 has received its explanation from the  
fact  that the disease is the result of 
the presence of the microscopic         
organism1 ,panhistophyton4    ,such     
being the facts with respect to the     
,pbrine1 what are the  indications as to
 the method of preventing it8 ,it is    
obvious that this  depends upon the way 
in which the ,panhistophyton is         
generated4 ,if it  may be generated by  
,abiogenesis1 or by ,xenogenesis1 within
 the silkworm  or its moth1 the         
extirpation of the disease must depend  
upon the  prevention of the occurrence  
of the conditions under which this      
generation takes place4 ,but if1 on the 
other hand1 the ,panhistophyton  is an  
independent organism1 which is no more  
generated by the silkworm  than the     
mistletoe is generated by the apple-tree
 or the oak on which it  grows1 though  

it may need the silkworm for its        
development in the same  way as the     
mistletoe needs the tree1 then the      
indications are totally  different4 ,the
 sole thing to be done is to get rid of 
and keep away the  germs of the         
,panhistophyton4 ,as might be imagined1 
from the course of  his previous        
investigations1 ,m4 ,pasteur was led to 
believe that the  latter was the right  
theory2 and1 guided by that theory1 he  
has devised a  method of extirpating the
 disease1 which has proved to be        
completely  successful wherever it has  
been properly carried out4    ,there can
 be no reason1 then1 for doubting that1 
among insects1  contagious and          
infectious diseases1 of great malignity1
 are caused by  minute organisms which  
are produced from pre-existing germs1 or
 by  homogenesis2 and there is no       
reason1 that ,i know of1 for believing  
that  what happens in insects may not   
take place in the highest animals4      
,indeed1 there is already strong        

evidence that some diseases of an       
extremely malignant and fatal character 
to which man is subject1 are as  much   
the work of minute organisms as is the  
,pbrine4 ,i refer for this  evidence to 
the very striking facts adduced by      
,professor ,lister in his  various      
well-known publications on the          
antiseptic method of treatment4 ,it     
appears to me impossible to rise from   
the perusal of those publications       
without a strong conviction that the    
lamentable mortality which so           
frequently dogs the footsteps of the    
most skilful operator1 and those  deadly
 consequences of wounds and injuries    
which seem to haunt the very  walls of  
great hospitals1 and are1 even now1     
destroying more men than die  of bullet 
or bayonet1 are due to the importation  
of minute organisms into  wounds1 and   
their increase and multiplication2 and  
that the surgeon who  saves most lives  
will be he who best works out the       
practical consequences  of the          

hypothesis of ,redi4    ,i commenced    
this ,address by asking you to follow me
 in an attempt to  trace the path which 
has been followed by a scientific idea1 
in its long  and slow progress from the 
position of a probable hypothesis to    
that of  an established law of nature4  
,our survey has not taken us into very  
attractive regions2 it has lain1        
chiefly1 in a land flowing with the     
abominable1 and peopled with mere grubs 
and mouldiness4 ,and it may be  imagined
 with what smiles and shrugs1 practical 
and serious  contemporaries of ,redi and
 of ,spallanzani may have commented on  
the waste  of their high abilities in   
toiling at the solution of problems     
which1  though curious enough in        
themselves1 could be of no conceivable  
utility  to mankind4    ,nevertheless1  
you will have observed that before we   
had travelled very  far upon our road1  
there appeared1 on the right hand and on
 the left1  fields laden with a harvest 
of golden grain1 immediately convertible

 into  those things which the most      
solidly practical men will admit to have
  value--viz41 money and life4    ,the  
direct loss to ,france caused by the    
,pbrine in seventeen years cannot  be   
estimated at less than fifty millions   
sterling2 and if we add to this  what   
,redi's idea1 in ,pasteur's hands1 has  
done for the wine-grower and  for the   
vinegar-maker1 and try to capitalise its
 value1 we shall find  that it will go a
 long way towards repairing the money   
losses caused by  the frightful and     
calamitous war of this autumn4 ,and as  
to the equivalent  of ,redi's thought in
 life1 how can we over-estimate the     
value of that  knowledge of the nature  
of epidemic and epizootic diseases1 and 
consequently of the means of checking1  
or eradicating them1 the dawn of  which 
has assuredly commenced8    ,looking    
back no further than ten years1 it is   
possible to select three  7#ahfc1 #ahfd1
 and #ahfi7 in which the total number of
 deaths from scarlet-  fever alone      

amounted to ninety thousand4 ,that is   
the return of killed1  the maimed and   
disabled being left out of sight4 ,why1 
it is to be hoped  that the list of     
killed in the present bloodiest of all  
wars will not  amount to more than this6
 ,but the facts which ,i have placed    
before you  must leave the least        
sanguine without a doubt that the nature
 and the  causes of this scourge will1  
one day1 be as well understood as those 
of  the ,pbrine are now2 and that the   
long-suffered massacre of our innocents 
will come to an end4    ,and thus       
mankind will have one more admonition   
that the people perish  for lack of     
knowledge2 and that the alleviation of  
the miseries1 and the  promotion of the 
welfare1 of men must be sought1 by those
 who will not  lose their pains1 in that
 diligent1 patient1 loving study of all 
the  multitudinous aspects of ,nature1  
the results of which constitute exact   
knowledge1 or ,science4 ,it is the      
justification and the glory of this     

great meeting that it is gathered       
together for no other object than the   
advancement of the moiety of science    
which deals with those phenomena of     
nature which we call physical4 ,may its 
endeavours be crowned with a full       
measure of success6        ,,ix         
,,geological ,,contemporaneity ,,and    
,,persistent ,,types ,,of ,,life        
#ahfb    ,merchants occasionally go     
through a wholesome1 though troublesome 
and not  always satisfactory1 process   
which they term taking stock4 ,after all
  the excitement of speculation1 the    
pleasure of gain1 and the pain of  loss1
 the trader makes up his mind to face   
facts and to learn the exact  quantity  
and quality of his solid and reliable   
possessions4    ,the man of science does
 well sometimes to imitate this         
procedure2 and1  forgetting for the time
 the importance of his own small        
winnings1 to re-  examine the common    
stock in trade1 so that he may make sure
 how far the  stock of bullion in the   

cellar--on the faith of whose existence 
so much  paper has been circulating--is 
really the solid gold of truth4    ,the 
,anniversary ,meeting of the ,geological
 ,society seems to be an occasion  well 
suited for an undertaking of this       
kind--for an inquiry1 in fact1  into the
 nature and value of the present results
 of palaeontological  investigation2 and
 the more so1 as all those who have paid
 close  attention to the late           
multitudinous discussions in which      
palaeontology is  implicated1 must have 
felt the urgent necessity of some such  
scrutiny4    ,first in order1 as the    
most definite and unquestionable of all 
the  results of palaeontology1 must be  
mentioned the immense extension and     
impulse given to botany1 zoology1 and   
comparative anatomy1 by the             
investigation of fossil remains4        
,indeed1 the mass of biological facts   
has  been so greatly increased1 and the 
range of biological speculation has     
been so vastly widened1 by the          

researches of the geologist and         
palaeontologist1 that it is to be feared
 there are naturalists in  existence who
 look upon geology as ,brindley regarded
 rivers4 ,rivers1  said the great       
engineer1 were made to feed canals2 and 
geology1 some  seem to think1 was solely
 created to advance comparative anatomy4
    ,were such a thought justifiable1 it
 could hardly expect to be received     
with favour by this assembly4 ,but it is
 not justifiable4 ,your favourite       
science has her own great aims          
independent of all others2 and if1      
notwithstanding her steady devotion to  
her own progress1 she can scatter  such 
rich alms among her sisters1 it should  
be remembered that her  charity is of   
the sort that does not impoverish1 but  
blesseth him that  gives and him that   
takes4    ,regard the matter as we will1
 however1 the facts remain4 ,nearly     
#dj1jjj  species of animals and plants  
have been added to the ,systema ,naturae
 by  palaeontological research4 ,this is

 a living population equivalent to that 
of a new continent in mere number2      
equivalent to that of a new  hemisphere1
 if we take into account the small      
population of insects as  yet found     
fossil1 and the large proportion and    
peculiar organisation of  many of the   
,vertebrata4    ,but1 beyond this1 it is
 perhaps not too much to say that1      
except for the  necessity of            
interpreting palaeontological facts1 the
 laws of distribution  would have       
received less careful study2 while few  
comparative anatomists  7and those not  
of the first order7 would have been     
induced by mere love  of detail1 as     
such1 to study the minutiae of          
osteology1 were it not that  in such    
minutiae lie the only keys to the most  
interesting riddles offered  by the     
extinct animal world4    ,these         
assuredly are great and solid gains4    
,surely it is matter for no  small      
congratulation that in half a century   
7for palaeontology1 though it  dawned   

earlier1 came into full day only with   
,cuvier7 a subordinate branch  of       
biology should have doubled the value   
and the interest of the whole  group of 
sciences to which it belongs4    ,but   
this is not all4 ,allied with geology1  
palaeontology has established  two laws 
of inestimable importance3 the first1   
that one and the same area  of the      
earth's surface has been successively   
occupied by very different  kinds of    
living beings2 the second1 that the     
order of succession  established in one 
locality holds good1 approximately1 in  
all4    ,the first of these laws is     
universal and irreversible2 the second  
is an  induction from a vast number of  
observations1 though it may possibly1   
and  even probably1 have to admit of    
exceptions4 ,as a consequence of the    
second law1 it follows that a peculiar  
relation frequently subsists  between   
series of strata containing organic     
remains1 in different  localities4 ,the 
series resemble one another not only in 

virtue of a  general resemblance of the 
organic remains in the two1 but also in 
virtue  of a resemblance in the order   
and character of the serial succession  
in  each4 ,there is a resemblance of    
arrangement2 so that the separate terms 
of each series1 as well as the whole    
series1 exhibit a correspondence4       
,succession implies time2 the lower     
members of an undisturbed series of     
sedimentary rocks are certainly older   
than the upper2 and when the notion  of 
age was once introduced as the          
equivalent of succession1 it was no     
wonder that correspondence in succession
 came to be looked upon as a            
correspondence in age1 or               
contemporaneity4 ,and1 indeed1 so long  
as  relative age only is spoken of1     
correspondence in succession is         
correspondence in age2 it is relative   
contemporaneity4    ,but it would have  
been very much better for geology if so 
loose and  ambiguous a word as          
contemporaneous had been excluded from  

her  terminology1 and if1 in its stead1 
some term expressing similarity of      
serial relation1 and excluding the      
notion of time altogether1 had been     
employed to denote correspondence in    
position in two or more series of       
strata4    ,in anatomy1 where such      
correspondence of position has          
constantly to be  spoken of1 it is      
denoted by the word homology and its    
derivatives2 and  for ,geology 7which   
after all is only the anatomy and       
physiology of the  earth7 it might be   
well to invent some single word1 such as
 homotaxis  7similarity of order71 in   
order to express an essentially similar 
idea4  ,this1 however1 has not been     
done1 and most probably the inquiry will
 at  once be made--,to what end burden  
science with a new and strange term in  
place of one old1 familiar1 and part of 
our common language8    ,the reply to   
this question will become obvious as the
 inquiry into the  results of           
palaeontology is pushed further4        

,those whose business it is to acquaint 
themselves specially with the  works of 
palaeontologists1 in fact1 will be fully
 aware that very few1 if  any1 would    
rest satisfied with such a statement of 
the conclusions of  their branch of     
biology as that which has just been     
given4    ,our standard repertories of  
palaeontology profess to teach us far   
higher  things--to disclose the entire  
succession of living forms upon the     
surface of the globe2 to tell us of a   
wholly different distribution of        
climatic conditions in ancient times2 to
 reveal the character of the  first of  
all living existences2 and to trace out 
the law of progress from  them to us4   
,it may not be unprofitable to bestow on
 these professions a somewhat more      
critical examination than they have     
hitherto received1 in order to          
ascertain how far they rest on an       
irrefragable basis2 or whether1 after   
all1 it might not be well for           
palaeontologists to learn a little more 

carefully that scientific ars artium1   
the art of saying ,i don't know4  ,and  
to this end let us define somewhat more 
exactly the extent of these  pretensions
 of palaeontology4    ,every one is     
aware that ,professor ,bronn's          
,untersuchungen and ,professor          
,pictet's ,trait de ,palontologie are   
works of standard authority1  familiarly
 consulted by every working             
palaeontologist4 ,it is desirable to    
speak of these excellent books1 and of  
their distinguished authors1 with  the  
utmost respect1 and in a tone as far as 
possible removed from carping           
criticism2 indeed1 if they are specially
 cited in this place1 it is  merely in  
justification of the assertion that the 
following propositions1  which may be   
found implicitly1 or explicitly1 in the 
works in question1  are regarded by the 
mass of palaeontologists and geologists1
 not only on  the ,continent but in this
 country1 as expressing some of the     
best-  established results of           

palaeontology4 ,thus3--    ,animals and 
plants began their existence together1  
not long after the  commencement of the 
deposition of the sedimentary rocks2 and
 then  succeeded one another1 in such a 
manner1 that totally distinct faunae and
  florae occupied the whole surface of  
the earth1 one after the other1 and     
during distinct epochs of time4    ,a   
geological formation is the sum of all  
the strata deposited over the  whole    
surface of the earth during one of these
 epochs3 a geological fauna  or flora is
 the sum of all the species of animals  
or plants which  occupied the whole     
surface of the globe1 during one of     
these epochs4    ,the population of the 
earth's surface was at first very       
similar in all  parts1 and only from the
 middle of the ,tertiary epoch onwards1 
began to  show a distinct distribution  
in zones4    ,the constitution of the   
original population1 as well as the     
numerical  proportions of its members1  
indicates a warmer and1 on the whole1   

somewhat tropical climate1 which        
remained tolerably equable throughout   
the year4 ,the subsequent distribution  
of living beings in zones is the  result
 of a gradual lowering of the general   
temperature1 which first  began to be   
felt at the poles4    ,it is not now    
proposed to inquire whether these       
doctrines are true or  false2 but to    
direct your attention to a much simpler 
though very  essential preliminary      
question--,what is their logical basis8 
what are the  fundamental assumptions   
upon which they all logically depend8   
and what is  the evidence on which those
 fundamental propositions demand our    
assent8    ,these assumptions are two3  
the first1 that the commencement of the 
geological record is coval with the     
commencement of life on the globe2  the 
second1 that geological contemporaneity 
is the same thing as  chronological     
synchrony4 ,without the first of these  
assumptions there  would of course be no
 ground for any statement respecting the

  commencement of life2 without the     
second1 all the other statements cited1 
every one of which implies a knowledge  
of the state of different parts of  the 
earth at one and the same time1 will be 
no less devoid of  demonstration4       
,the first assumption obviously rests   
entirely on negative evidence4 ,this    
is1 of course1 the only evidence that   
ever can be available to prove the      
commencement of any series of phenomena2
 but1 at the same time1 it must  be     
recollected that the value of negative  
evidence depends entirely on  the amount
 of positive corroboration it receives4 
,if ,a4,b4 wishes to prove  an alibi1 it
 is of no use for him to get a thousand 
witnesses simply to  swear that they did
 not see him in such and such a place1  
unless the  witnesses are prepared to   
prove that they must have seen him had  
he been  there4 ,but the evidence that  
animal life commenced with the ,lingula-
  flags1 e4g41 would seem to be exactly 
of this unsatisfactory  uncorroborated  

sort4 ,the ,cambrian witnesses simply   
swear they haven't  seen anybody their  
way2 upon which the counsel for the     
other side  immediately puts in ten or  
twelve thousand feet of ,devonian       
sandstones to  make oath they never saw 
a fish or a mollusk1 though all the     
world knows  there were plenty in their 
time4    ,but then it is urged that1    
though the ,devonian rocks in one part  
of the  world exhibit no fossils1 in    
another they do1 while the lower        
,cambrian  rocks nowhere exhibit        
fossils1 and hence no living being could
 have  existed in their epoch4    ,to   
this there are two replies3 the first   
that the observational basis of  the    
assertion that the lowest rocks are     
nowhere fossiliferous is an  amazingly  
small one1 seeing how very small an     
area1 in comparison to that  of the     
whole world1 has yet been fully         
searched2 the second1 that the  argument
 is good for nothing unless the         
unfossiliferous rocks in question  were 

not only contemporaneous in the         
geological sense1 but  synchronous in   
the chronological sense4 ,to use the    
alibi illustration  again4 ,if a man    
wishes to prove he was in neither of two
 places1 ,a and ,b1  on a given day1 his
 witnesses for each place must be       
prepared to answer  for the whole day4  
,if they can only prove that he was not 
at ,a in the  morning1 and not at ,b in 
the afternoon1 the evidence of his      
absence from  both is nil1 because he   
might have been at ,b in the morning and
 at ,a in  the afternoon4    ,thus      
everything depends upon the validity of 
the second assumption4 ,and  we must    
proceed to inquire what is the real     
meaning of the word  contemporaneous as 
employed by geologists4 ,to this end a  
concrete  example may be taken4    ,the 
,lias of ,england and the ,lias of      
,germany1 the ,cretaceous rocks of      
,britain and the ,cretaceous rocks of   
,southern ,india1 are termed by         
geologists contemporaneous formations2  

but whenever any thoughtful  geologist  
is asked whether he means to say that   
they were deposited  synchronously1 he  
says1 ,no1--only within the same great  
epoch4 ,and if1  in pursuing the        
inquiry1 he is asked what may be the    
approximate value in  time of a great   
epoch--whether it means a hundred years1
 or a thousand1  or a million1 or ten   
million years--his reply is1 ,i cannot  
tell4    ,if the further question be    
put1 whether physical geology is in     
possession  of any method by which the  
actual synchrony 7or the reverse7 of any
 two  distant deposits can be           
ascertained1 no such method can be heard
 of2 it  being admitted by all the best 
authorities that neither similarity of  
mineral composition1 nor of physical    
character1 nor even direct  continuity  
of stratum1 are absolute proofs of the  
synchronism of even  approximated       
sedimentary strata3 while1 for distant  
deposits1 there seems  to be no kind of 
physical evidence attainable of a nature

 competent to  decide whether such      
deposits were formed simultaneously1 or 
whether they  possess any given         
difference of antiquity4 ,to return to  
an example  already given3 ,all         
competent authorities will probably     
assent to the  proposition that physical
 geology does not enable us in any way  
to reply  to this question--,were the   
,british ,cretaceous rocks deposited at 
the same  time as those of ,india1 or   
are they a million of years younger or a
  million of years older8    ,is        
palaeontology able to succeed where     
physical geology fails8 ,standard       
writers on palaeontology1 as has been   
seen1 assume that she can4 ,they take   
it for granted1 that deposits containing
 similar organic remains are            
synchronous--at any rate in a broad     
sense2 and yet1 those who will study    
the eleventh and twelfth chapters of    
,sir ,henry ,de ,la ,beche's remarkable 
,researches in ,theoretical ,geology1   
published now nearly thirty years  ago1 

and will carry out the arguments there  
most luminously stated1 to  their       
logical consequences1 may very easily   
convince themselves that even  absolute 
identity of organic contents is no proof
 of the synchrony of  deposits1 while   
absolute diversity is no proof of       
difference of date4 ,sir  ,henry ,de ,la
 ,beche goes even further1 and adduces  
conclusive evidence to  show that the   
different parts of one and the same     
stratum1 having a  similar composition  
throughout1 containing the same organic 
remains1 and  having similar beds above 
and below it1 may yet differ to any     
conceivable  extent in age4    ,edward  
,forbes was in the habit of asserting   
that the similarity of the  organic     
contents of distant formations was prima
 facie evidence1 not of  their          
similarity1 but of their difference of  
age2 and holding as he did  the doctrine
 of single specific centres1 the        
conclusion was as legitimate  as any    
other2 for the two districts must have  

been occupied by migration  from one of 
the two1 or from an intermediate spot1  
and the chances  against exact          
coincidence of migration and of         
imbedding are infinite4    ,in point of 
fact1 however1 whether the hypothesis of
 single or of  multiple specific centres
 be adopted1 similarity of organic      
contents  cannot possibly afford any    
proof of the synchrony of the deposits  
which  contain them2 on the contrary1 it
 is demonstrably compatible with the    
lapse of the most prodigious intervals  
of time1 and with the  interposition of 
vast changes in the organic and         
inorganic worlds1  between the epochs in
 which such deposits were formed4    ,on
 what amount of similarity of their     
faunae is the doctrine of the           
contemporaneity of the ,european and of 
the ,north ,american ,silurians  based8 
,in the last edition of ,sir ,charles   
,lyell's ,elementary ,geology it  is    
stated1 on the authority of a former    
,president of this ,society1 the  late  

,daniel ,sharpe1 that between #cj and   
#dj per cent4 of the species of         
,silurian ,mollusca are common to both  
sides of the ,atlantic4 ,by way of due  
allowance for further discovery1 let us 
double the lesser number and  suppose   
that #fj per cent4 of the species are   
common to the ,north ,american  and the 
,british ,silurians4 ,sixty per cent4 of
 species in common is1 then1  proof of  
contemporaneity4    ,now suppose that1 a
 million or two of years hence1 when    
,britain has made  another dip beneath  
the sea and has come up again1 some     
geologist applies  this doctrine1 in    
comparing the strata laid bare by the   
upheaval of the  bottom1 say1 of ,st4   
,george's ,channel with what may then   
remain of the  ,suffolk ,crag4          
,reasoning in the same way1 he will at  
once decide the  ,suffolk ,crag and the 
,st4 ,george's ,channel beds to be      
contemporaneous2  although we happen to 
know that a vast period 7even in the    
geological  sense7 of time1 and physical

 changes of almost unprecedented extent1
  separate the two4 ,but if it be a     
demonstrable fact that strata           
containing more than #fj or #gj per     
cent4 of species of ,mollusca in common1
  and comparatively close together1 may 
yet be separated by an amount of        
geological time sufficient to allow of  
some of the greatest physical  changes  
the world has seen1 what becomes of that
 sort of contemporaneity  the sole      
evidence of which is a similarity of    
facies1 or the identity of  half a dozen
 species1 or of a good many genera8     
,and yet there is no better evidence for
 the contemporaneity assumed by  all who
 adopt the hypothesis of universal      
faunae and florae1 of a  universally    
uniform climate1 and of a sensible      
cooling of the globe  during geological 
time4    ,there seems1 then1 no escape  
from the admission that neither physical
  geology1 nor palaeontology1 possesses 
any method by which the absolute        
synchronism of two strata can be        

demonstrated4 ,all that geology can     
prove  is local order of succession4 ,it
 is mathematically certain that1 in any 
given vertical linear section of an     
undisturbed series of sedimentary       
deposits1 the bed which lies lowest is  
the oldest4 ,in many other vertical     
linear sections of the same series1 of  
course1 corresponding beds will  occur  
in a similar order2 but1 however great  
may be the probability1 no  man can say 
with absolute certainty that the beds in
 the two sections  were synchronously   
deposited4 ,for areas of moderate       
extent1 it is  doubtless true that no   
practical evil is likely to result from 
assuming  the corresponding beds to be  
synchronous or strictly contemporaneous2
 and  there are multitudes of accessory 
circumstances which may fully justify   
the assumption of such synchrony4 ,but  
the moment the geologist has to  deal   
with large areas1 or with completely    
separated deposits1 the  mischief of    
confounding that homotaxis or similarity

 of arrangement1  which can be          
demonstrated1 with synchrony or identity
 of date1 for  which there is not a     
shadow of proof1 under the one common   
term of  contemporaneity becomes        
incalculable1 and proves the constant   
source of  gratuitous speculations4     
,for anything that geology or           
palaeontology are able to show to the   
contrary1 a ,devonian fauna and flora in
 the ,british ,islands may have been    
contemporaneous with ,silurian life in  
,north ,america1 and with a             
,carboniferous fauna and flora in       
,africa4 ,geographical provinces and    
zones  may have been as distinctly      
marked in the ,palaeozoic epoch as at   
present1  and those seemingly sudden    
appearances of new genera and species1  
which  we ascribe to new creation1 may  
be simple results of migration4    ,it  
may be so2 it may be otherwise4 ,in the 
present condition of our  knowledge and 
of our methods1 one verdict--not proven1
 and not  provable--must be recorded    

against all the grand hypotheses of the 
palaeontologist respecting the general  
succession of life on the globe4  ,the  
order and nature of terrestrial life1 as
 a whole1 are open questions4  ,geology 
at present provides us with most        
valuable topographical records1  but she
 has not the means of working them into 
a universal history4 ,is  such a        
universal history1 then1 to be regarded 
as unattainable8 ,are all  the grandest 
and most interesting problems which     
offer themselves to the  geological     
student1 essentially insoluble8 ,is he  
in the position of a  scientific        
,tantalus--doomed always to thirst for a
 knowledge which he  cannot obtain8 ,the
 reverse is to be hoped2 nay1 it may not
 be impossible  to indicate the source  
whence help will come4    ,in commencing
 these remarks1 mention was made of the 
great obligations  under which the      
naturalist lies to the geologist and    
palaeontologist4  ,assuredly the time   
will come when these obligations will be

 repaid  tenfold1 and when the maze of  
the world's past history1 through which 
the  pure geologist and the pure        
palaeontologist find no guidance1 will  
be  securely threaded by the clue       
furnished by the naturalist4    ,all who
 are competent to express an opinion on 
the subject are1 at  present1 agreed    
that the manifold varieties of animal   
and vegetable form  have not either come
 into existence by chance1 nor result   
from capricious  exertions of creative  
power2 but that they have taken place in
 a definite  order1 the statement of    
which order is what men of science term 
a natural  law4 ,whether such a law is  
to be regarded as an expression of the  
mode of  operation of natural forces1 or
 whether it is simply a statement of the
  manner in which a supernatural power  
has thought fit to act1 is a  secondary 
question1 so long as the existence of   
the law and the  possibility of its     
discovery by the human intellect are    
granted4 ,but he  must be a half-hearted

 philosopher who1 believing in that     
possibility1  and having watched the    
gigantic strides of the biological      
sciences during  the last twenty years1 
doubts that science will sooner or later
 make this  further step1 so as to      
become possessed of the law of evolution
 of  organic forms--of the unvarying    
order of that great chain of causes and 
effects of which all organic forms1     
ancient and modern1 are the links4  ,and
 then1 if ever1 we shall be able to     
begin to discuss1 with profit1 the      
questions respecting the commencement of
 life1 and the nature of the  successive
 populations of the globe1 which so many
 seem to think are  already answered4   
,the preceding arguments make no        
particular claim to novelty2 indeed they
  have been floating more or less       
distinctly before the minds of          
geologists  for the last thirty years2  
and if1 at the present time1 it has     
seemed  desirable to give them more     
definite and systematic expression1 it  

is  because palaeontology is every day  
assuming a greater importance1 and now  
requires to rest on a basis the firmness
 of which is thoroughly well  assured4  
,among its fundamental conceptions1     
there must be no confusion  between what
 is certain and what is more or less    
probable4#a ,but1  pending the          
construction of a surer foundation than 
palaeontology now  possesses1 it may be 
instructive1 assuming for the nonce the 
general  correctness of the ordinary    
hypothesis of geological                
contemporaneity1 to  consider whether   
the deductions which are ordinarily     
drawn from the whole  body of           
palaeontological facts are justifiable4 
,footnote #a3 ,le plus grand service    
qu'on puisse rendre  la science est  d'y
 faire place nette avant d'y rien       
construire4--,,cuvier4    ,the evidence 
on which such conclusions are based is  
of two kinds1  negative and positive4   
,the value of negative evidence1 in     
connection with  this inquiry1 has been 

so fully and clearly discussed in an    
address from  the chair of this         
,society1#b which none of us have       
forgotten1 that  nothing need at present
 be said about it2 the more1 as the     
considerations  which have been laid    
before you have certainly not tended to 
increase  your estimation of such       
evidence4 ,it will be preferable to turn
 to the  positive facts of              
palaeontology1 and to inquire what they 
tell us4    ,footnote #b3 ,anniversary  
,address for #ahea1 ,quart4 ,journ4     
,geol4 ,soc4  vol4 vii4    ,we are all  
accustomed to speak of the number and   
the extent of the  changes in the living
 population of the globe during         
geological time as  something enormous3 
and indeed they are so1 if we regard    
only the  negative differences which    
separate the older rocks from the more  
modern1  and if we look upon specific   
and generic changes as great changes1   
which  from one point of view1 they     
truly are4 ,but leaving the negative    

differences out of consideration1 and   
looking only at the positive data       
furnished by the fossil world from a    
broader point of view--from that of  the
 comparative anatomist who has made the 
study of the greater  modifications of  
animal form his chief business--a       
surprise of another  kind dawns upon the
 mind2 and under this aspect the        
smallness of the  total change becomes  
as astonishing as was its greatness     
under the other4    ,there are two      
hundred known orders of plants2 of these
 not one is  certainly known to exist   
exclusively in the fossil state4 ,the   
whole lapse  of geological time has as  
yet yielded not a single new ordinal    
type of  vegetable structure4#c         
,footnote #c3 ,see ,hooker's            
,introductory ,essay to the ,flora of   
,tasmania1  p4 xxiii4    ,the positive  
change in passing from the recent to the
 ancient animal  world is greater1 but  
still singularly small4 ,no fossil      
animal is so  distinct from those now   

living as to require to be arranged even
 in a  separate class from those which  
contain existing forms4 ,it is only when
  we come to the orders1 which may be   
roughly estimated at about a hundred    
and thirty1 that we meet with fossil    
animals so distinct from those now      
living as to require orders for         
themselves2 and these do not amount1 on 
the most liberal estimate1 to more than 
about #aj per cent4 of the whole4       
,there is no certainly known extinct    
order of ,protozoa2 there is but one    
among the ,coelenterata--that of the    
rugose corals2 there is none among  the 
,mollusca2 there are three1 the         
,cystidea1 ,blastoidea1 and             
,edrioasterida1 among the ,echinoderms2 
and two1 the ,trilobita and             
,eurypterida1 among the ,crustacea2     
making altogether five for the great    
sub-kingdom of ,annulosa4 ,among        
,vertebrates there is no ordinally      
distinct  fossil fish3 there is only one
 extinct order of ,amphibia--the        

,labyrinthodonts2 but there are at least
 four distinct orders of ,reptilia1     
viz4 the ,ichthyosauria1 ,plesiosauria1 
,pterosauria1 ,dinosauria1 and  perhaps 
another or two4 ,there is no known      
extinct order of ,birds1 and no         
certainly known extinct order of        
,mammals1 the ordinal distinctness of   
the  ,toxodontia being doubtful4    ,the
 objection that broad statements of this
 kind1 after all1 rest largely  on      
negative evidence is obvious1 but it has
 less force than may at first  be       
supposed2 for1 as might be expected from
 the circumstances of the  case1 we     
possess more abundant positive evidence 
regarding ,fishes and  marine ,mollusks 
than respecting any other forms of      
animal life2 and yet  these offer us1   
through the whole range of geological   
time1 no species  ordinally distinct    
from those now living2 while the far    
less numerous  class of ,echinoderms    
presents three1 and the ,crustacea two1 
such orders1  though none of these come 

down later than the ,palaeozoic age4    
,lastly1 the  ,reptilia present the     
extraordinary and exceptional phenomenon
 of as many  extinct as existing orders1
 if not more2 the four mentioned        
maintaining  their existence from the   
,lias to the ,chalk inclusive4    ,some 
years ago one of your ,secretaries      
pointed out another kind of  positive   
palaeontological evidence tending       
towards the same conclusion--  afforded 
by the existence of what he termed      
persistent types of  vegetable and of   
animal life4#d ,he stated1 on the       
authority of ,dr4  ,hooker1 that there  
are ,carboniferous plants which appear  
to be  generically identical with some  
now living2 that the cone of the        
,oolitic  ,araucaria is hardly          
distinguishable from that of an existing
 species2  that a true ,pinus appears in
 the ,purbecks and a ,juglans in the    
,chalk2  while1 from the ,bagshot       
,sands1 a ,banksia1 the wood of which is
 not  distinguishable from that of      

species now living in ,australia1 had   
been  obtained4    ,footnote #d3 ,see   
the abstract of a ,lecture ,on the      
,persistent ,types of  ,animal ,life1 in
 the ,notices of the ,meetings of the   
,royal ,institution of  ,great          
,britain4--,june #c1 #ahei1 vol4 iii4 p4
 #aea4    ,turning to the animal        
kingdom1 he affirmed the tabulate corals
 of the  ,silurian rocks to be          
wonderfully like those which now exist2 
while even  the families of the ,aporosa
 were all represented in the older      
,mesozoic  rocks4    ,among the         
,mollusca similar facts were adduced4   
,let it be borne in mind  that ,avicula1
 ,mytilus1 ,chiton1 ,natica1 ,patella1  
,trochus1 ,discina1  ,orbicula1         
,lingula1 ,rhynchonclla1 and ,nautilus1 
all of which are  existing genera1 are  
given without a doubt as ,silurian in   
the last  edition of ,siluria2 while the
 highest forms of the highest           
,cephalopods  are represented in the    
,lias by a genus ,belemnoteuthis1 which 

presents  the closest relation to the   
existing ,loligo4    ,the two highest   
groups of the ,annulosa1 the ,insecta   
and the ,arachnida1  are represented in 
the ,coal1 either by existing genera1 or
 by forms  differing from existing      
genera in quite minor peculiarities4    
,turning to the ,vertebrata1 the only   
palaeozoic ,elasmobranch ,fish of which 
we have any complete knowledge is the   
,devonian and ,carboniferous            
,pleuracanthus1 which differs no more   
from existing ,sharks than these do     
from one another4    ,again1 vast as is 
the number of undoubtedly ,ganoid fossil
 ,fishes1 and  great as is their range  
in time1 a large mass of evidence has   
recently  been adduced to show that     
almost all those respecting which we    
possess  sufficient information1 are    
referable to the same sub-ordinal groups
 as  the existing ,lepidosteus1         
,polypterus1 and ,sturgeon2 and that a  
singular  relation obtains between the  
older and the younger ,fishes2 the      

former1  the ,devonian ,ganoids1 being  
almost all members of the same sub-order
 as  ,polypterus1 while the ,mesozoic   
,ganoids are almost all similarly allied
  to ,lepidosteus4#e    ,footnote #e3   
,memoirs of the ,geological ,survey of  
the ,united ,kingdom4--  ,decade x4     
,preliminary ,essay upon the ,systematic
 ,arrangement of the ,fishes  of the    
,devonian ,epoch4    ,again1 what can be
 more remarkable than the singular      
constancy of  structure preserved       
throughout a vast period of time by the 
family of the  ,pycnodonts and by that  
of the true ,coelacanths2 the former    
persisting1  with but insignificant     
modifications1 from the ,carboniferous  
to the  ,tertiary rocks1 inclusive2 the 
latter existing1 with still less change1
  from the ,carboniferous rocks to the  
,chalk1 inclusive8    ,among ,reptiles1 
the highest living group1 that of the   
,crocodilia1 is  represented1 at the    
early part of the ,mesozoic epoch1 by   
species  identical in the essential     

characters of their organisation with   
those  now living1 and differing from   
the latter only in such matters as the  
form of the articular facets of the     
vertebral centra1 in the extent to      
which the nasal passages are separated  
from the cavity of the mouth by  bone1  
and in the proportions of the limbs4    
,and even as regards the ,mammalia1 the 
scanty remains of ,triassic and         
,oolitic species afford no foundation   
for the supposition that the            
organisation of the oldest forms        
differed nearly so much from some of    
those which now live as these differ    
from one another4    ,it is needless to 
multiply these instances2 enough has    
been said to  justify the statement     
that1 in view of the immense diversity  
of known  animal and vegetable forms1   
and the enormous lapse of time indicated
 by  the accumulation of fossiliferous  
strata1 the only circumstance to be     
wondered at is1 not that the changes of 
life1 as exhibited by positive          

evidence1 have been so great but that   
they have been so small4    ,be they    
great or small1 however1 it is desirable
 to attempt to estimate  them4 ,let us1 
therefore1 take each great division of  
the animal world in  succession1 and1   
whenever an order or a family can be    
shown to have had a  prolonged          
existence1 let us endeavour to ascertain
 how far the later  members of the group
 differ from the earlier ones4 ,if these
 later  members1 in all or in many      
cases1 exhibit a certain amount of      
modification1 the fact is1 so far1      
evidence in favour of a general law of  
change2 and1 in a rough way1 the        
rapidity of that change will be measured
  by the demonstrable amount of         
modification4 ,on the other hand1 it    
must be  recollected that the absence of
 any modification1 while it may leave   
the  doctrine of the existence of a law 
of change without positive support1     
cannot possibly disprove all forms of   
that doctrine1 though it may afford  a  

sufficient refutation of many of them4  
,the ,,protozoa4--,the ,protozoa are    
represented throughout the whole range  
of  geological series1 from the ,lower  
,silurian formation to the present day4 
,the most ancient forms recently made   
known by ,ehrenberg are exceedingly     
like those which now exist3 no one has  
ever pretended that the difference      
between any ancient and any modern      
,foraminifera is of more than generic   
value1 nor are the oldest ,foraminifera 
either simpler1 more embryonic1 or  less
 differentiated1 than the existing      
forms4    ,the ,,coelenterata4--,the    
,tabulate ,corals have existed from the 
,silurian  epoch to the present day1 but
 ,i am not aware that the ancient       
,heliolites possesses a single mark of a
 more embryonic or less  differentiated 
character1 or less high organisation1   
than the existing  ,heliopora4 ,as for  
the ,aporose ,corals1 in what respect is
 the ,silurian  ,paloeocyclus less      
highly organised or more embryonic than 

the modern  ,fungia1 or the ,liassic    
,aporosa than the existing members of   
the same  families8    ,the             
,mollusca--,in what sense is the living 
,waldheimia less embryonic1  or more    
specialised1 than the palaeozoic        
,spirifer2 or the existing              
,rhynchonelloe1 ,cranioe1 ,discinoe1    
,linguloe1 than the ,silurian species   
of the same genera8 ,in what sense can  
,loligo or ,spirula be said to be  more 
specialised1 or less embryonic1 than    
,belemnites2 or the modern  species of  
,lamellibranch and ,gasteropod genera1  
than the ,silurian species  of the same 
genera8    ,the ,,annulosa4--,the       
,carboniferous ,insecta and ,arachnida  
are neither less  specialised1 nor more 
embryonic1 than these that now live1 nor
 are the  ,liassic ,cirripedia and      
,macrura2 while several of the          
,brachyura1 which  appear in the ,chalk1
 belong to existing genera2 and none    
exhibit either  an intermediate1 or an  
embryonic1 character4    ,the           

,,vertebrata4--,among fishes ,i have    
referred to the ,coelacanthini          
7comprising the genera ,coelacanthus1   
,holophagus1 ,undina1 and  ,macropoma7  
as affording an example of a persistent 
type2 and it is most  remarkable to note
 the smallness of the differences       
between any of these  fishes 7affecting 
at most the proportions of the body and 
fins1 and the  character and sculpture  
of the scales71 notwithstanding their   
enormous  range in time4 ,in all the    
essentials of its very peculiar         
structure1 the  ,macropoma of the ,chalk
 is identical with the ,coelacanthus of 
the  ,coal4 ,look at the genus          
,lepidotus1 again1 persisting without a 
modification of importance from the     
,liassic to the ,eocene formations      
inclusively4    ,or among the           
,teleostei--in what respect is the      
,beryx of the ,chalk more  embryonic1 or
 less differentiated1 than ,beryx       
lineatus of ,king ,george's  ,sound8    
,or to turn to the higher               

,vertebrata--in what sense are the      
,liassic  ,chelonia inferior to those   
which now exist8 ,how are the           
,cretaceous  ,ichthyosauria1            
,plesiosauria1 or ,pterosauria less     
embryonic1 or more  differentiated1     
species than those of the ,lias8    ,or 
lastly1 in what circumstance is the     
,phascolotherium more embryonic1  or of 
a more generalised type1 than the modern
 ,opossum2 or a ,lophiodon1  or a       
,paloeotherium1 than a modern ,tapirus  
or ,hyrax8    ,these examples might be  
almost indefinitely multiplied1 but     
surely they  are sufficient to prove    
that the only safe and unquestionable   
testimony  we can procure--positive     
evidence--fails to demonstrate any sort 
of  progressive modification towards a  
less embryonic1 or less generalised1    
type in a great many groups of animals  
of long-continued geological  existence4
 ,in these groups there is abundant     
evidence of variation--none  of what is 
ordinarily understood as progression2   

and1 if the known  geological record is 
to be regarded as even any considerable 
fragment of  the whole1 it is           
inconceivable that any theory of a      
necessarily  progressive development can
 stand1 for the numerous orders and     
families  cited afford no trace of such 
a process4    ,but it is a most         
remarkable fact1 that1 while the groups 
which have been  mentioned1 and many    
besides1 exhibit no sign of progressive 
modification1  there are others1        
co-existing with them1 under the same   
conditions1 in  which more or less      
distinct indications of such a process  
seems to be  traceable4 ,among such     
indications ,i may remind you of the    
predominance of  ,holostome ,gasteropoda
 in the older rocks as compared with    
that of  ,siphonostone ,gasteropoda in  
the later4 ,a case less open to the     
objection  of negative evidence1        
however1 is that afforded by the        
,tetrabranchiate  ,cephalopoda1 the     
forms of the shells and of the septal   

sutures exhibiting  a certain increase  
of complexity in the newer genera4      
,here1 however1 one  is met at once with
 the occurrence of ,orthoceras and      
,baculites at the  two ends of the      
series1 and of the fact that one of the 
simplest genera1  ,nautilus1 is that    
which now exists4    ,the ,crinoidea1 in
 the abundance of stalked forms in the  
ancient  formations as compared with    
their present rarity1 seem to present us
 with  a fair case of modification from 
a more embryonic towards a less         
embryonic condition4 ,but then1 on      
careful consideration of the facts1 the 
objection arises that the stalk1 calyx1 
and arms of the palaeozoic ,crinoid  are
 exceedingly different from the         
corresponding organs of a larval        
,comatula2 and it might with perfect    
justice be argued that  ,actinocrinus   
and ,eucalyptocrinus1 for example1      
depart to the full as  widely1 in one   
direction1 from the stalked embryo of   
,comatula1 as  ,comatula itself does in 

the other4    ,the ,echinidea1 again1   
are frequently quoted as exhibiting a   
gradual  passage from a more generalised
 to a more specialised type1 seeing that
  the elongated1 or oval1 ,spatangoids  
appear after the spheroidal  ,echinoids4
 ,but here it might be argued1 on the   
other hand1 that the  spheroidal        
,echinoids1 in reality1 depart further  
from the general plan  and from the     
embryonic form than the elongated       
,spatangoids do2 and that  the peculiar 
dental apparatus and the pedicellariae  
of the former are  marks of at least as 
great differentiation as the petaloid   
ambulacra and  semitae of the latter4   
,once more1 the prevalence of ,macrurous
 before ,brachyurous ,podophthalmia  is1
 apparently1 a fair piece of evidence in
 favour of progressive  modification in 
the same order of ,crustacea2 and yet   
the case will not  stand much sifting1  
seeing that the ,macrurous              
,podophthalmia depart as far  in one    
direction from the common type of       

,podophthalmia1 or from any  embryonic  
condition of the ,brachyura1 as the     
,brachyura do in the other2  and that   
the middle terms between ,macrura and   
,brachyura--the ,anomura--are  little   
better represented in the older         
,mesozoic rocks than the ,brachyura     
are4    ,none of the cases of           
progressive modification which are cited
 from among  the ,invertebrata appear to
 me to have a foundation less open to   
criticism  than these2 and if this be   
so1 no careful reasoner would1 ,i think1
 be  inclined to lay very great stress  
upon them4 ,among the ,vertebrata1      
however1 there are a few examples which 
appear to be far less open to           
objection4    ,it is1 in fact1 true of  
several groups of ,vertebrata which have
 lived  through a considerable range of 
time1 that the endoskeleton 7more       
particularly the spinal column7 of the  
older genera presents a less  ossified1 
and1 so far1 less differentiated1       
condition than that of the  younger     

genera4 ,thus the ,devonian ,ganoids1   
though almost all members of  the same  
sub-order as ,polypterus1 and presenting
 numerous important  resemblances to the
 existing genus1 which possesses        
biconclave vertebrae1  are1 for the most
 part1 wholly devoid of ossified        
vertebral centra4 ,the  ,mesozoic       
,lepidosteidae1 again1 have1 at most1   
biconcave vertebrae1 while  the existing
 ,lepidosteus has ,salamandroid1        
opisthocoelous1 vertebrae4  ,so1 none of
 the ,palaeozoic ,sharks have shown     
themselves to be possessed of  ossified 
vertebrae1 while the majority of modern 
,sharks possess such  vertebrae4 ,again1
 the more ancient ,crocodilia and       
,lacertilia have vertebrae  with the    
articular facets of their centra        
flattened or biconcave1 while  the      
modern members of the same group have   
them procoelous4 ,but the most          
remarkable examples of progressive      
modification of the vertebral column1   
in correspondence with geological age1  

are those afforded by the  ,pycnodonts  
among fish1 and the ,labyrinthodonts    
among ,amphibia4    ,the late able      
ichthyologist ,heckel pointed out the   
fact1 that1 while the  ,pycnodonts never
 possess true vertebral centra1 they    
differ in the degree  of expansion and  
extension of the ends of the bony arches
 of the vertebrae  upon the sheath of   
the notochord2 the ,carboniferous forms 
exhibiting  hardly any such expansion1  
while the ,mesozoic genera present a    
greater  and greater development1 until1
 in the ,tertiary forms1 the expanded   
ends  become suturally united so as to  
form a sort of false vertebra4 ,hermann 
von ,meyer1 again1 to whose luminous    
researches we are indebted for our      
present large knowledge of the          
organisation of the older               
,labyrinthodonts1  has proved that the  
,carboniferous ,archegosaurus had very  
imperfectly  developed vertebral centra1
 while the ,triassic ,mastodonsaurus had
 the  same parts completely ossified4#f 

,footnote #f3 ,as this ,address is      
passing through the press 7,march #g1   
#ahfb71 evidence lies before me of the  
existence of a new ,labyrinthodont      
7,pholidogaster71 from the ,edinburgh   
coal-field with well-ossified  vertebral
 centra4    ,the regularity and evenness
 of the dentition of the ,anoplotherium1
 as  contrasted with that of existing   
,artiodactyles1 and the assumed nearer  
approach of the dentition of certain    
ancient ,carnivores to the typical      
arrangement1 have also been cited as    
exemplifications of a law of            
progressive development1 but ,i know of 
no other cases based on positive        
evidence which are worthy of particular 
notice4    ,what then does an impartial 
survey of the positively ascertained    
truths  of palaeontology testify in     
relation to the common doctrines of     
progressive modification1 which suppose 
that modification to have taken  place  
by a necessary progress from more to    
less embryonic forms1 or from  more to  

less generalised types1 within the      
limits of the period  represented by the
 fossiliferous rocks8    ,it negatives  
those doctrines2 for it either shows us 
no evidence of any  such modification1  
or demonstrates it to have been very    
slight2 and as to  the nature of that   
modification1 it yields no evidence     
whatsoever that  the earlier members of 
any long-continued group were more      
generalised in  structure than the later
 ones4 ,to a certain extent1 indeed1 it 
may be  said that imperfect ossification
 of the vertebral column is an embryonic
  character2 but1 on the other hand1 it 
would be extremely incorrect to  suppose
 that the vertebral columns of the older
 ,vertebrata are in any  sense embryonic
 in their whole structure4              
,obviously1 if the earliest             
fossiliferous rocks now known are coval 
with  the commencement of life1 and if  
their contents give us any just         
conception of the nature and the extent 
of the earliest fauna and flora1  the   

insignificant amount of modification    
which can be demonstrated to  have taken
 place in any one group of animals1 or  
plants1 is quite  incompatible with the 
hypothesis that all living forms are the
 results of  a necessary process of     
progressive development1 entirely       
comprised within  the time represented  
by the fossiliferous rocks4             
,contrariwise1 any admissible hypothesis
 of progressive modification must  be   
compatible with persistence without     
progression1 through indefinite         
periods4 ,and should such an hypothesis 
eventually be proved to be true1  in the
 only way in which it can be            
demonstrated1 viz4 by observation and   
experiment upon the existing forms of   
life1 the conclusion will  inevitably   
present itself1 that the ,palaeozoic    
,mesozoic1 and ,cainozoic  faunae and   
florae1 taken together1 bear somewhat   
the same proportion to the  whole series
 of living beings which have occupied   
this globe1 as the  existing fauna and  

flora do to them4    ,such are the      
results of palaeontology as they appear1
 and have for some  years appeared1 to  
the mind of an inquirer who regards that
 study simply  as one of the            
applications of the great biological    
sciences1 and who  desires to see it    
placed upon the same sound basis as     
other branches of  physical inquiry4 ,if
 the arguments which have been brought  
forward are  valid1 probably no one1 in 
view of the present state of opinion1   
will be  inclined to think the time     
wasted which has been spent upon their  
elaboration4        ,x      ,,geological
 ,,reform    #ahfi    ,a great reform in
 geological speculation seems now to    
have become  necessary4    ,it is quite 
certain that a great mistake has been   
made--that ,british  popular geology at 
the present time is in direct opposition
 to the  principles of ,natural         
,philosophy4#a    ,footnote #a3 ,on     
,geological ,time4 ,by ,sir ,w4         
,thomson1 ,,ll4,d4 ,transactions  of the

 ,geological ,society of ,glasgow1 vol4 
iii4    ,in reviewing the course of     
geological thought during the past year1
 for  the purpose of discovering those  
matters to which ,i might most fitly    
direct your attention in the ,address   
which it now becomes my duty to  deliver
 from the ,presidential ,chair1 the two 
somewhat alarming sentences  which ,i   
have just read1 and which occur in an   
able and interesting essay  by an       
eminent natural philosopher1 rose into  
such prominence before my  mind that    
they eclipsed everything else4    ,it   
surely is a matter of paramount         
importance for the ,british geologists  
7some of them very popular geologists   
too7 here in solemn annual session      
assembled1 to inquire whether the severe
 judgment thus passed upon them  by so  
high an authority as ,sir ,william      
,thomson is one to which they must      
plead guilty sans phrase1 or whether    
they are prepared to say not  guilty1   
and appeal for a reversal of the        

sentence to that higher court  of       
educated scientific opinion to which we 
are all amenable4    ,as your           
attorney-general for the time being1 ,i 
thought ,i could not do  better than get
 up the case with a view of advising    
you4 ,it is true that  the charges      
brought forward by the other side       
involve the consideration  of matters   
quite foreign to the pursuits with which
 ,i am ordinarily  occupied2 but1 in    
that respect1 ,i am only in the position
 which is1 nine  times out of ten1      
occupied by counsel1 who nevertheless   
contrive to gain  their causes1 mainly  
by force of mother-wit and common-sense1
 aided by  some training in other       
intellectual exercises4    ,nerved by   
such precedents1 ,i proceed to put my   
pleading before you4    ,and the first  
question with which ,i propose to deal  
is1 ,what is it to  which ,sir ,w4      
,thomson refers when he speaks of       
geological speculation  and ,british    
popular geology8    ,i find three1 more 

or less contradictory1 systems of       
geological thought1  each of which might
 fairly enough claim these appellations1
 standing side  by side in ,britain4 ,i 
shall call one of them ,,catastrophism1 
another  ,,uniformitarianism1 the third 
,,evolutionism2 and ,i shall try briefly
 to  sketch the characters of each1 that
 you may say whether the  classification
 is1 or is not1 exhaustive4    ,by      
,,catastrophism1 ,i mean any form of    
geological speculation which1 in  order 
to account for the phenomena of geology1
 supposes the operation of  forces      
different in their nature1 or           
immeasurably different in power1  from  
those which we at present see in action 
in the universe4    ,the ,mosaic        
cosmogony is1 in this sense1            
catastrophic1 because it assumes  the   
operation of extra-natural power4 ,the  
doctrine of violent upheavals1  dbcles1 
and cataclysms in general1 is           
catastrophic1 so far as it  assumes that
 these were brought about by causes     

which have now no  parallel4 ,there was 
a time when catastrophism might1        
pre-eminently1 have  claimed the title  
of ,british popular geology2 and        
assuredly it has yet  many adherents1   
and reckons among its supporters some of
 the most  honoured members of this     
,society4    ,by ,,uniformitarianism1 ,i
 mean especially1 the teaching of       
,hutton and of  ,lyell4    ,that great  
though incomplete work1 ,the ,theory of 
the ,earth1 seems to me  to be one of   
the most remarkable contributions to    
geology which is  recorded in the annals
 of the science4 ,so far as the         
not-living world is  concerned1         
uniformitarianism lies there1 not only  
in germ1 but in blossom  and fruit4     
,if one asks how it is that ,hutton was 
led to entertain views so far in        
advance of those prevalent in his time1 
in some respects2 while1 in  others1    
they seem almost curiously limited1 the 
answer appears to me to  be plain4      
,hutton was in advance of the geological

 speculation of his time1 because1  in  
the first place1 he had amassed a vast  
store of knowledge of the facts  of     
geology1 gathered by personal           
observation in travels of considerable  
extent2 and because1 in the second      
place1 he was thoroughly trained in  the
 physical and chemical science of his   
day1 and thus possessed1 as much  as any
 one in his time could possess it1 the  
knowledge which is requisite  for the   
just interpretation of geological       
phenomena1 and the habit of  thought    
which fits a man for scientific inquiry4
    ,it is to this thorough scientific  
training that ,i ascribe ,hutton's      
steady  and persistent refusal to look  
to other causes than those now in       
operation1 for the explanation of       
geological phenomena4    ,thus he       
writes3--,i do not pretend1 as he ,m4 de
 ,luc does in his theory1  to describe  
the beginning of things4 ,i take things 
such as ,i find them at  present2 and   
from these ,i reason with regard to that

 which must have  been4#b    ,footnote  
#b3 ,the ,theory of the ,earth1 vol4 i4 
p4 #agc1 note4    ,and again3--,a theory
 of the earth1 which has for object     
truth1 can have  no retrospect to that  
which had preceded the present order of 
the world2  for this order alone is what
 we have to reason upon2 and to reason  
without data is nothing but delusion4 ,a
 theory1 therefore1 which is  limited to
 the actual constitution of this earth  
cannot be allowed to  proceed one step  
beyond the present order of things4#c   
,footnote #c3 ,ibid41 vol4 i4 p4 #bha4  
,and so clear is he1 that no causes     
beside such as are now in operation  are
 needed to account for the character and
 disposition of the components  of the  
crust of the earth1 that he says1       
broadly and boldly3-- 444 ,there  is no 
part of the earth which has not had the 
same origin1 so far as this  consists in
 that earth being collected at the      
bottom of the sea1 and  afterwards      
produced1 as land1 along with masses of 

melted substances1 by  the operation of 
mineral causes4#d    ,footnote #d3      
,ibid44 p4 #cga4    ,but other          
influences were at work upon ,hutton    
beside those of a mind  logical by      
nature1 and scientific by sound         
training2 and the peculiar  turn which  
his speculations took seems to me to be 
unintelligible1 unless  these be taken  
into account4 ,the arguments of the     
,french astronomers and  mathematicians1
 which1 at the end of the last century1 
were held to  demonstrate the existence 
of a compensating arrangement among the 
celestial bodies1 whereby all           
perturbations eventually reduced        
themselves  to oscillations on each side
 of a mean position1 and the stability  
of the  solar system was secured1 had   
evidently taken strong hold of ,hutton's
  mind4    ,in those oddly constructed  
periods which seem to have prejudiced   
many  persons against reading his works1
 but which are full of that peculiar1   
if unattractive1 eloquence which flows  

from mastery of the subject1  ,hutton   
says3--    ,we have now got to the end  
of our reasoning2 we have no data       
further to  conclude immediately from   
that which actually is4 ,but we have got
 enough2  we have the satisfaction to   
find1 that in ,nature there is wisdom1  
system1  and consistency4 ,for having1  
in the natural history of this earth1   
seen a  succession of worlds1 we may    
from this conclude that there is a      
system in  ,nature2 in like manner as1  
from seeing revolutions of the planets1 
it is  concluded1 that there is a system
 by which they are intended to continue 
those revolutions4 ,but if the          
succession of worlds is established in  
the  system of nature1 it is in vain to 
look for anything higher in the origin  
of the earth4 ,the result1 therefore1 of
 this physical inquiry is1 that we  find
 no vestige of a beginning1--no prospect
 of an end4#e    ,footnote #e3 ,ibid41  
vol4 i4 p4 #bjj4    ,yet another        
influence worked strongly upon ,hutton4 

,like most philosophers  of his age1 he 
coquetted with those final causes which 
have been named  barren virgins1 but    
which might be more fitly termed the    
hetairoe of  philosophy1 so constantly  
have they led men astray4 ,the final    
cause of  the existence of the world is1
 for ,hutton1 the production of life and
  intelligence4    ,we have now         
considered the globe of this earth as a 
machine1 constructed  upon chemical as  
well as mechanical principles1 by which 
its different  parts are all adapted1 in
 form1 in quality1 and in quantity1 to a
 certain  end2 an end attained with     
certainty or success2 and an end from   
which we  may perceive wisdom1 in       
contemplating the means employed4       
,but is this world to be considered thus
 merely as a machine1 to last no  longer
 than its parts retain their present    
position1 their proper forms  and       
qualities8 ,or may it not be also       
considered as an organised body8  such  
as has a constitution in which the      

necessary decay of the machine is       
naturally repaired1 in the exertion of  
those productive powers by which  it had
 been formed4    ,this is the view in   
which we are now to examine the globe2  
to see if  there be1 in the constitution
 of this world1 a reproductive          
operation1 by  which a ruined           
constitution may be again repaired1 and 
a duration or  stability thus procured  
to the machine1 considered as a world   
sustaining  plants and animals4#f       
,footnote #f3 ,ibid41 vol4 i4 pp4 #af1  
#ag4    ,kirwan1 and the other          
,philistines of the day1 accused ,hutton
 of declaring  that his theory implied  
that the world never had a beginning1   
and never  differed in condition from   
its present state4 ,nothing could be    
more  grossly unjust1 as he expressly   
guards himself against any such         
conclusion in the following terms3--    
,but in thus tracing back the natural   
operations which have succeeded  each   
other1 and mark to us the course of time

 past1 we come to a period  in which we 
cannot see any farther4 ,this1 however1 
is not the beginning  of the operations 
which proceed in time and according to  
the wise economy  of this world2 nor is 
it the establishing of that which1 in   
the course of  time1 had no beginning2  
it is only the limit of our             
retrospective view of  those operations 
which have come to pass in time1 and    
have been conducted  by supreme         
intelligence4#g    ,footnote #g3 ,ibid41
 vol4 i4 p4 #bbc4    ,i have spoken of  
,uniformitarianism as the doctrine of   
,hutton and of  ,lyell4 ,if ,i have     
quoted the older writer rather than the 
newer1 it is  because his works are     
little known1 and his claims on our     
veneration too  frequently forgotten1   
not because ,i desire to dim the fame of
 his eminent  successor4 ,few of the    
present generation of geologists have   
read  ,playfair's ,illustrations1 fewer 
still the original ,theory of the       
,earth2 the more is the pity2 but which 

of us has not thumbed every page  of the
 ,principles of ,geology8 ,i think that 
he who writes fairly the  history of his
 own progress in geological thought1    
will not be able to  separate his debt  
to ,hutton from his obligations to      
,lyell2 and the  history of the progress
 of individual geologists is the history
 of  geology4      ,no one can doubt    
that the influence of uniformitarian    
views has been  enormous1 and1 in the   
main1 most beneficial and favourable to 
the  progress of sound geology4    ,nor 
can it be questioned that               
,uniformitarianism has even a stronger  
title  than ,catastrophism to call      
itself the geological speculation of    
,britain1  or1 if you will1 ,british    
popular geology4 ,for it is eminently a 
,british  doctrine1 and has even now    
made comparatively little progress on   
the  continent of ,europe4              
,nevertheless1 it seems to me to be open
 to serious  criticism upon one of its  
aspects4    ,i have shown how unjust was

 the insinuation that ,hutton denied a  
beginning to the world4 ,but it would   
not be unjust to say that he            
persistently in practice1 shut his eyes 
to the existence of that prior  and     
different state of things which1 in     
theory1 he admitted2 and1 in this       
aversion to look beyond the veil of     
stratified rocks1 ,lyell follows him4   
,hutton and ,lyell alike agree in their 
indisposition to carry their            
speculations a step beyond the period   
recorded in the most ancient strata  now
 open to observation in the crust of the
 earth4 ,this is1 for ,hutton1  the     
point in which we cannot see any        
farther2 while ,lyell tells us1--       
,the astronomer may find good reasons   
for ascribing the earth's form to  the  
original fluidity of the mass1 in times 
long antecedent to the first            
introduction of living beings into the  
planet2 but the geologist must be       
content to regard the earliest monuments
 which it is his task to  interpret1 as 

belonging to a period when the crust had
 already acquired  great solidity and   
thickness1 probably as great as it now  
possesses1 and  when volcanic rocks1 not
 essentially differing from those now   
produced1  were formed from time to     
time1 the intensity of volcanic heat    
being  neither greater nor less than it 
is now4#h    ,footnote #h3 ,principles  
of ,geology1 vol4 ii4 p4 #baa4    ,and  
again1 ,as geologists1 we learn that it 
is not only the present  condition of   
the globe which has been suited to the  
accommodation of  myriads of living     
creatures1 but that many former states  
also have been  adapted to the          
organisation and habits of prior races  
of beings4 ,the  disposition of the     
seas1 continents and islands1 and the   
climates1 have  varied2 the species     
likewise have been changed2 and yet they
 have all  been so modelled1 on types   
analogous to those of existing plants   
and  animals1 as to indicate1           
throughout1 a perfect harmony of design 

and  unity of purpose4 ,to assume that  
the evidence of the beginning1 or end1  
of so vast a scheme lies within the     
reach of our philosophical inquiries1   
or even of our speculations1 appears to 
be inconsistent with a just  estimate of
 the relations which subsist between the
 finite powers of man  and the          
attributes of an infinite and eternal   
,being4#i    ,footnote #i3 ,ibid41 vol4 
ii4 p4 #fac4    ,the limitations implied
 in these passages appear to me to      
constitute the  weakness and the logical
 defect of ,uniformitarianism4 ,no one  
will impute  blame to ,hutton that1 in  
face of the imperfect condition1 in his 
day1 of  those physical sciences which  
furnish the keys to the riddles of      
geology1  he should have thought it     
practical wisdom to limit his theory to 
an  attempt to account for the present  
order of things2 but ,i am at a loss  to
 comprehend why1 for all time1 the      
geologist must be content to regard  the
 oldest fossiliferous rocks as the      

ultima ,thule of his science2 or  what  
there is inconsistent with the relations
 between the finite and the  infinite   
mind1 in the assumption1 that we may    
discern somewhat of the  beginning1 or  
of the end1 of this speck in space we   
call our earth4 ,the  finite mind is    
certainly competent to trace out the    
development of the  fowl within the egg2
 and ,i know not on what ground it      
should find more  difficulty in         
unravelling the complexities ,of the    
development of the  earth4 ,in fact1 as 
,kant has well remarked1#aj the cosmical
 process is  really simpler than the    
biological4    ,footnote #aj3 ,man darf 
es sich also nicht befremden lassen1    
wenn ich  mich unterstehe zu sagen1 dass
 eher die ,bildung aller ,himmelskrper1 
die  ,ursache ihrer ,bewegungen1 kurz   
der ,ursprung der gantzen gegenwrtigen  
,verfassung des ,weltbaues werden knnen 
eingesehen werden1 ehe die  ,erzeugung  
eines einzigen ,krautes oder einer      
,raupe aus mechanischen  ,grnden1       

deutlich und vollstndig kund werden     
wird4--,,kant',s ,smmtliche  ,werke1    
,bd4 i4 p4 #bbj4    ,this attempt to    
limit1 at a particular point1 the       
progress of inductive  and deductive    
reasoning from the things which are1 to 
those which were--  this faithlessness  
to its own logic1 seems to me to have   
cost  ,uniformitarianism the place1 as  
the permanent form of geological        
speculation1 which it might otherwise   
have held4    ,it remains that ,i should
 put before you what ,i understand to be
 the third  phase of geological         
speculation--namely1 ,,evolutionism4    
,i shall not make what ,i have to say on
 this head clear1 unless ,i diverge1  or
 seem to diverge1 for a while1 from the 
direct path of my discourse1 so  far as 
to explain what ,i take to be the scope 
of geology itself4 ,i  conceive geology 
to be the history of the earth1 in      
precisely the same  sense as biology is 
the history of living beings2 and ,i    
trust you will  not think that ,i am    

overpowered by the influence of a       
dominant pursuit if  ,i say that ,i     
trace a close analogy between these two 
histories4    ,if ,i study a living     
being1 under what heads does the        
knowledge ,i obtain  fall8 ,i can learn 
its structure1 or what we call its      
,,anatomy2 and its  ,,development1 or   
the series of changes which it passes   
through to acquire  its complete        
structure4 ,then ,i find that the living
 being has certain  powers resulting    
from its own activities1 and the        
interaction of these  with the          
activities of other things--the         
knowledge of which is  ,,physiology4    
,beyond this the living being has a     
position in space and  time1 which is   
its ,,distribution4 ,all these form the 
body of ascertainable  facts which      
constitute the status quo of the living 
creature4 ,but these  facts have their  
causes2 and the ascertainment of these  
causes is the  doctrine of ,,aetiology4 
,if we consider what is knowable about  

the earth1 we shall find that such      
earth-knowledge--if ,i may so translate 
the word geology--falls into the  same  
categories4    ,what is termed          
stratigraphical geology is neither more 
nor less than the  anatomy of the earth2
 and the history of the succession of   
the formations  is the history of a     
succession of such anatomies1 or        
corresponds with  development1 as       
distinct from generation4    ,the       
internal heat of the earth1 the         
elevation and depression of its  crust1 
its belchings forth of vapours1 ashes1  
and lava1 are its  activities1 in as    
strict a sense as are warmth and the    
movements and  products of respiration  
the activities of an animal4 ,the       
phenomena of the  seasons1 of the trade 
winds1 of the ,gulf-stream1 are as much 
the results  of the reaction between    
these inner activities and outward      
forces1 as are  the budding of the      
leaves in spring and their falling in   
autumn the  effects of the interaction  

between the organisation of a plant and 
the  solar light and heat4 ,and1 as the 
study of the activities of the living   
being is called its physiology1 so are  
these phenomena the subject-matter  of  
an analogous telluric physiology1 to    
which we sometimes give the name  of    
meteorology1 sometimes that of physical 
geography1 sometimes that of  geology4  
,again1 the earth has a place in space  
and in time1 and relations  to other    
bodies in both these respects1 which    
constitute its  distribution4 ,this     
subject is usually left to the          
astronomer2 but a  knowledge of its     
broad outlines seems to me to be an     
essential  constituent of the stock of  
geological ideas4    ,all that can be   
ascertained concerning the structure1   
succession of  conditions1 actions1 and 
position in space of the earth1 is the  
matter of  fact of its natural history4 
,but1 as in biology1 there remains the  
matter  of reasoning from these facts to
 their causes1 which is just as much    

science as the other1 and indeed more2  
and this constitutes geological         
aetiology4    ,having regard to this    
general scheme of geological knowledge  
and thought1  it is obvious that        
geological speculation may be1 so to    
speak1 anatomical  and developmental    
speculation1 so far as it relates to    
points of  stratigraphical arrangement  
which are out of reach of direct        
observation2  or1 it may be             
physiological speculation so far as it  
relates to  undetermined problems       
relative to the activities of the earth2
 or1 it may  be distributional          
speculation1 if it deals with           
modifications of the  earth's place in  
space2 or1 finally1 it will be          
aetiological speculation  if it attempts
 to deduce the history of the world1 as 
a whole1 from the  known properties of  
the matter of the earth1 in the         
conditions in which  the earth has been 
placed4    ,for the purposes of the     
present discourse ,i may take this last 

to be what  is meant by geological      
speculation4    ,now ,uniformitarianism1
 as we have seen1 tends to ignore       
geological  speculation in this sense   
altogether4    ,the one point the       
catastrophists and the uniformitarians  
agreed upon1  when this ,society was    
founded1 was to ignore it4 ,and you will
 find1 if  you look back into our       
records1 that our revered fathers in    
geology  plumed themselves a good deal  
upon the practical sense and wisdom of  
this  proceeding4 ,as a temporary       
measure1 ,i do not presume to challenge 
its  wisdom2 but in all organised bodies
 temporary changes are apt to produce   
permanent effects2 and as time has      
slipped by1 altering all the  conditions
 which may have made such mortification 
of the scientific flesh  desirable1 ,i  
think the effect of the stream of cold  
water which has  steadily flowed over   
geological speculation within these     
walls has been  of doubtful beneficence4
    ,the sort of geological speculation 

to which ,i am now referring            
7geological aetiology1 in short7 was    
created1 as a science1 by that famous   
philosopher ,immanuel ,kant1 when1 in   
#agge1 he wrote his ,general ,natural   
,history and ,theory of the ,celestial  
,bodies2 or an ,attempt to account for  
the ,constitutional and the ,mechanical 
,origin of the ,universe upon           
,newtonian principles4#aa    ,footnote  
#aa3 ,grant 7,history of ,physical      
,astronomy1 p4 #egd7 makes but  the     
briefest reference to ,kant4    ,in this
 very remarkable but seemingly          
little-known treatise1#ab ,kant         
expounds a complete cosmogony1 in the   
shape of a theory of the causes  which  
have led to the development of the      
universe from diffused atoms of  matter 
endowed with simple attractive and      
repulsive forces4    ,footnote #ab3     
,allgemeine ,naturgeschichte und        
,theorie des ,himmels2 oder  ,versuch   
von der ,verfassung und dem mechanischen
 ,ursprunge des ganzen  ,weltgebudes    

nach ,newton'schen ,grundsatzen         
abgehandelt4--,,kant',s  ,smmtliche     
,werke1 ,bd4 i4 p4 #bjg4    ,give me    
matter1 says ,kant1 and ,i will build   
the world2 and he  proceeds to deduce   
from the simple data from which he      
starts1 a doctrine  in all essential    
respects similar to the well-known      
,nebular ,hypothesis  of ,laplace4#ac   
,he accounts for the relation of the    
masses and the  densities of the planets
 to their distances from the sun1 for   
the  eccentricities of their orbits1 for
 their rotations1 for their  satellites1
 for the general agreement in the       
direction of rotation among  the        
celestial bodies1 for ,saturn's ring1   
and for the zodiacal light4 ,he  finds  
in each system of worlds1 indications   
that the attractive force of  the       
central mass will eventually destroy its
 organisation1 by  concentrating upon   
itself the matter of the whole system2  
but1 as the  result of this             
concentration1 he argues for the        

development of an amount  of heat which 
will dissipate the mass once more into a
 molecular chaos  such as that in which 
it began4    ,footnote #ac3 ,systme du  
,monde1 tome ii4 chap4 #f4    ,kant     
pictures to himself the universe as once
 an infinite expansion of  formless and 
diffused matter4 ,at one point of this  
he supposes a single  centre of         
attraction set up2 and1 by strict       
deductions from admitted  dynamical     
principles1 shows how this must result  
in the development of a  prodigious     
central body1 surrounded by systems of  
solar and planetary  worlds in all      
stages of development4 ,in vivid        
language he depicts the  great          
world-maelstrom1 widening the margins of
 its prodigious eddy in the  slow       
progress of millions of ages1 gradually 
reclaiming more and more of  the        
molecular waste1 and converting chaos   
into cosmos4 ,but what is gained  at the
 margin is lost in the centre2 the      
attractions of the central  systems     

bring their constituents together1 which
 then1 by the heat  evolved1 are        
converted once more into molecular      
chaos4 ,thus the worlds  that are1 lie  
between the ruins of the worlds that    
have been1 and the  chaotic materials of
 the worlds that shall be2 and in spite 
of all waste  and destruction1 ,cosmos  
is extending his borders at the expense 
of ,chaos4    ,kant's further           
application of his views to the earth   
itself is to be  found in his ,treatise 
on ,physical ,geography#ad 7a term under
 which the  then unknown science of     
geology was included71 a subject which  
he had  studied with very great care and
 on which he lectured for many years4   
,the  fourth section of the first part  
of this ,treatise is called ,history of 
the great ,changes which the ,earth has 
formerly undergone and is still         
undergoing1 and is1 in fact1 a brief and
 pregnant essay upon the  principles of 
geology4 ,kant gives an account first of
 the gradual  changes which are now     

taking place under the heads of such as 
are caused  by earthquakes1 such as are 
brought about by rain and rivers1 such  
as are  effected by the sea1 such as are
 produced by winds and frost2 and1      
finally1 such as result from the        
operations of man4    ,footnote #ad3    
,kant's ,smmtliche ,werke1 ,bd4 viii4 p4
 #ade4    ,the second part is devoted to
 the ,memorials of the ,changes which   
the  ,earth has undergone in remote     
,antiquity4 ,these are enumerated       
as3--,a4  ,proofs that the sea formerly 
covered the whole earth4 ,b4 ,proofs    
that the  sea has often been changed    
into dry land and then again into sea4  
,c4 ,a  discussion of the various       
theories of the earth put forward by    
,scheuchzer1 ,moro1 ,bonnet1 ,woodward1 
,white1 ,leibnitz1 ,linnaeus1 and       
,buffon4    ,the third part contains an 
,attempt to give a sound explanation of 
the  ancient history of the earth4    ,i
 suppose that it would be very easy to  
pick holes in the details of  ,kant's   

speculations1 whether cosmological1 or  
specially telluric1 in  their           
application4 ,but for all that1 he seems
 to me to have been the  first person to
 frame a complete system of geological  
speculation by  founding the doctrine of
 evolution4    ,with as much truth as   
,hutton1 ,kant could say1 ,i take things
 just as ,i  find them at present1 and1 
from these1 ,i reason with regard to    
that which  must have been4 ,like       
,hutton1 he is never tired of pointing  
out that in  ,nature there is wisdom1   
system1 and consistency4 ,and1 as in    
these great  principles1 so in believing
 that the cosmos has a reproductive     
operation  by which a ruined            
constitution may be repaired1 he        
forestalls ,hutton2  while1 on the other
 hand1 ,kant is true to science4 ,he    
knows no bounds to  geological          
speculation but those of the intellect4 
,he reasons back to a  beginning of the 
present state of things2 he admits the  
possibility of an  end4    ,i have said 

that the three schools of geological    
speculation which ,i have  termed       
,catastrophism1 ,uniformitarianism1 and 
,evolutionism1 are commonly  supposed to
 be antagonistic to one another2 and ,i 
presume it will have  become obvious    
that in my belief1 the last is destined 
to swallow up the  other two4 ,but it is
 proper to remark that each of the      
latter has kept  alive the tradition of 
precious truths4    ,,catastrophism has 
insisted upon the existence of a        
practically unlimited  bank of force1 on
 which the theorist might draw2 and it  
has cherished the  idea of the          
development of the earth from a state in
 which its form1 and  the forces which  
it exerted1 were very different from    
those we now know4  ,that such          
difference of form and power once       
existed is a necessary part  of the     
doctrine of evolution4                  
,,uniformitarianism1 on the other hand1 
has with equal justice insisted  upon a 
practically unlimited bank of time1     

ready to discount any quantity  of      
hypothetical paper4 ,it has kept before 
our eyes the power of the  infinitely   
little1 time being granted1 and has     
compelled us to exhaust  known causes1  
before flying to the unknown4    ,to my 
mind there appears to be no sort of     
necessary theoretical  antagonism       
between ,catastrophism and              
,uniformitarianism4 ,on the contrary1   
it is very conceivable that catastrophes
 may be part and parcel of  uniformity4 
,let me illustrate my case by analogy4  
,the working of a clock  is a model of  
uniform action2 good time-keeping means 
uniformity of  action4 ,but the striking
 of the clock is essentially a          
catastrophe2 the  hammer might be made  
to blow up a barrel of gunpowder1 or    
turn on a  deluge of water2 and1 by     
proper arrangement1 the clock1 instead  
of  marking the hours1 might strike at  
all sorts of irregular periods1 never   
twice alike1 in the intervals1 force1 or
 number of its blows4  ,nevertheless1   

all these irregular1 and apparently     
lawless1 catastrophes  would be the     
result of an absolutely uniformitarian  
action2 and we might  have two schools  
of clock-theorists1 one studying the    
hammer and the  other the pendulum4     
,still less is there any necessary      
antagonists between either of these     
doctrines and that of ,evolution1 which 
embraces all that is sound in both      
,catastrophism and ,uniformitarianism1  
while it rejects the arbitrary          
assumptions of the one and the1 as      
arbitrary1 limitations of the other4    
,nor is the value of the doctrine of    
,evolution to the philosophic thinker   
diminished by the fact that it applies  
the same method to the living and  the  
not-living world2 and embraces1 in one  
stupendous analogy1 the growth  of a    
solar system from molecular chaos1 the  
shaping of the earth from the  nebulous 
cub-hood of its youth1 through          
innumerable changes and  immeasurable   
ages1 to its present form2 and the      

development of a living  being from the 
shapeless mass of protoplasm we term a  
germ4    ,i do not know whether         
,evolutionism can claim that amount of  
currency  which would entitle it to be  
called ,british popular geology2 but1   
more or  less vaguely1 it is assuredly  
present in the minds of most geologists4
    ,such being the three phases of     
geological speculation1 we are now in   
position to inquire which of these it is
 that ,sir ,william ,thomson calls  upon
 us to reform in the passages which ,i  
have cited4    ,it is obviously         
,uniformitarianism which the            
distinguished physicist takes  to be the
 representative of geological           
speculation in general4 ,and thus a     
first issue is raised1 inasmuch as many 
persons 7and those not the least        
thoughtful among the younger geologists7
 do not accept strict                   
,uniformitarianism as the final form of 
geological speculation4 ,we should  say1
 if ,hutton and ,playfair declare the   

course of the world to have been  always
 the same1 point out the fallacy by all 
means2 but1 in so doing1 do  not imagine
 that you are proving modern geology to 
be in opposition to  natural philosophy4
 ,i do not suppose that1 at the present 
day1 any  geologist would be found to   
maintain absolute ,uniformitarianism1 to
 deny  that the rapidity of the rotation
 of the earth may be diminishing1 that  
the sun may be waxing dim1 or that the  
earth itself may be cooling4  ,most of  
us1 ,i suspect1 are ,gallios1 who care  
for none of these things1  being of     
opinion that1 true or fictitious1 they  
have made no practical  difference to   
the earth1 during the period of which a 
record is preserved  in stratified      
deposits4    ,the accusation that we    
have been running counter to the        
principles of  natural philosophy1      
therefore1 is devoid of foundation4 ,the
 only question  which can arise is      
whether we have1 or have not1 been      
tacitly making  assumptions which are in

 opposition to certain conclusions which
 may be  drawn from those principles4   
,and this question subdivides itself    
into  two3--the first1 are we really    
contravening such conclusions8 the      
second1  if we are1 are those           
conclusions so firmly based that we may 
not  contravene them8 ,i reply in the   
negative to both these questions1 and ,i
  will give you my reasons for so doing4
 ,sir ,william ,thomson believes that   
he is able to prove1 by physical        
reasonings1 that the existing state of  
things on the earth1 life on the        
earth--all geological history showing   
continuity of life--must be limited     
within some such period of time as  one 
hundred million years 7loc4 cit4 p4     
#be74    ,the first inquiry which arises
 plainly is1 has it ever been denied    
that  this period may be enough for the 
purposes of geology8    ,the discussion 
of this question is greatly embarrassed 
by the vagueness  with which the assumed
 limit is1 ,i will not say defined1 but 

indicated1--  some such period of past  
time as one hundred million years4 ,now 
does  this mean that it may have been   
two1 or three1 or four hundred million  
years8 ,because this really makes all   
the difference4#ae    ,footnote #ae3    
,sir ,william ,thomson implies 7loc4    
cit4 p4 #af7 that the  precise time is  
of no consequence3 the principle is the 
same2 but1 as  the principle is         
admitted1 the whole discussion turns on 
its practical  results4    ,i presume   
that #ajj1jjj feet may be taken as a    
full allowance for the  total thickness 
of stratified rocks containing traces of
 life2 #ajj1jjj  divided by #ajj1jjj1jjj
  #j4jja4 ,consequently1 the deposit of 
#ajj1jjj feet  of stratified rock in    
#ajj1jjj1jjj years means that the       
deposit has taken  place at the rate of 
#a_/ajjj of a foot1 or1 say1 #a_/hc of  
an inch1 per  annum4    ,well1 ,i do not
 know that any one is prepared to       
maintain that1 even  making all needful 
allowances1 the stratified rocks may not

 have been  formed1 on the average1 at  
the rate of #a_/hc of an inch per annum4
 ,i  suppose that if such could be shown
 to be the limit of world-growth1 we    
could put up with the allowance without 
feeling that our speculations had       
undergone any revolution4 ,and perhaps1 
after all1 the qualifying phrase  some  
such period may not necessitate the     
assumption of more than #a_/aff  or     
#a_/bdi or #a_/ccb of an inch of deposit
 per year1 which1 of course1 would  give
 us still more ease and comfort4        
,but1 it may be said1 that it is        
biology1 and not geology1 which asks for
  so much time--that the succession of  
life demands vast intervals2 but  this  
appears to me to be reasoning in a      
circle4 ,biology takes her time  from   
geology4 ,the only reason we have for   
believing in the slow rate of  the      
change in living forms is the fact that 
they persist through a series  of       
deposits which1 geology informs us1 have
 taken a long while to make4  ,if the   

geological clock is wrong1 all the      
naturalist will have to do is  to modify
 his notions of the rapidity of change  
accordingly4 ,and ,i  venture to point  
out that1 when we are told that the     
limitation of the  period during which  
living beings have inhabited this planet
 to one1 two1  or three hundred million 
years requires a complete revolution in 
geological speculation1 the onus        
probandi rests on the maker of the      
assertion1 who brings forward not a     
shadow of evidence in its support4      
,thus1 if we accept the limitation of   
time placed before us by ,sir ,w4       
,thomson1 it is not obvious1 on the face
 of the matter1 that we shall have  to  
alter1 or reform1 our ways in any       
appreciable degree2 and we may          
therefore proceed with much calmness1   
and indeed much indifference1 as to  the
 result1 to inquire whether that        
limitation is justified by the          
arguments employed in its support4      
,these arguments are three in number4-- 

,i4 ,the first is based upon the        
undoubted fact that the tides tend to   
retard the rate of the earth's rotation 
upon its axis4 ,that this must be  so is
 obvious1 if one considers1 roughly1    
that the tides result from the  pull    
which the sun and the moon exert upon   
the sea1 causing it to act as  a sort of
 break upon the rotating solid earth4   
,kant1 who was by no means a mere       
abstract philosopher1 but a good        
mathematician and well versed in the    
physical science of his time1 not  only 
proved this in an essay of exquisite    
clearness and intelligibility1  now more
 than a century old1#af but deduced from
 it some of its more  important         
consequences1 such as the constant      
turning of one face of the  moon towards
 the earth4    ,footnote #af3           
,untersuchung der ,frage oh die ,erde in
 ihrer ,umdrehung um  die ,achse1       
wodurch sie die ,abwechselung des ,tages
 und der ,nacht  hervorbringt1 einige   
,vernderung seit den ersten ,zeiten     

ihres ,ursprunges  erlitten habe1       
c4--,,kant's ,smmntliche ,werke1 ,bd4 i4
 p4 #agh4    ,but there is a long step  
from the demonstration of a tendency to 
the  estimation of the practical value  
of that tendency1 which is all with     
which we are at present concerned4 ,the 
facts bearing on this point appear  to  
stand as follows3--    ,it is a matter  
of observation that the moon's mean     
motion is 7and has for  the last #c1jjj 
years been7 undergoing an acceleration1 
relatively to the  rotation of the      
earth4 ,of course this may result from  
one of two causes3  the moon may really 
have been moving more swiftly in its    
orbit2 or the  earth may have been      
rotating more slowly on its axis4       
,laplace believed he had accounted for  
this phenomenon by the fact that  the   
eccentricity of the earth's orbit has   
been diminishing throughout  these      
#c1jjj years4 ,this would produce a     
diminution of the mean attraction  of   
the sun on the moon2 or1 in other words1

 an increase in the attraction  of the  
earth on the moon2 and1 consequently1 an
 increase in the rapidity  of the       
orbital motion of the latter body4      
,laplace1 therefore1 laid the           
responsibility of the acceleration upon 
the moon1 and if his views were         
correct1 the tidal retardation must     
either be insignificant in amount1 or   
be counteracted by some other agency4   
,our great astronomer1 ,adams1 however1 
appears to have found a flaw in         
,laplace's calculation1 and to have     
shown that only half the observed       
retardation could be accounted for in   
the way he had suggested4 ,there        
remains1 therefore1 the other half to be
 accounted for2 and here1 in the        
absence of all positive knowledge1 three
 sets of hypotheses have been           
suggested4    7a47 ,m4 ,delaunay        
suggests that the earth is at fault1 in 
consequence of  the tidal retardation4  
,messrs4 ,adams1 ,thomson1 and ,tait    
work out this  suggestion1 and1 on a    

certain assumption as to the proportion 
of  retardations due to the sun and     
moon1 find the earth may lose twenty-two
  seconds of time in a century from this
 cause4#ag    ,footnote #ag3 ,sir ,w4   
,thomson1 loc4 cit4 p4 #ad4    7b47 ,but
 ,m4 ,dufour suggests that the          
retardation of the earth 7which is      
hypothetically assumed to exist7 may be 
due in part1 or wholly1 to the  increase
 of the moment of inertia of the earth  
by meteors falling upon  its surface4   
,this suggestion also meets with the    
entire approval of ,sir  ,w4 ,thomson1  
who shows that meteor-dust1 accumulating
 at the rate of one  foot in #d1jjj     
years1 would account for the remainder  
of retardation4#ah    ,footnote #ah3    
,ibid4 p4 #bg4    7c47 ,thirdly1 ,sir   
,w4 ,thomson brings forward an          
hypothesis of his own  with respect to  
the cause of the hypothetical           
retardation of the earth's  rotation3-- 
,let us suppose ice to melt from the    
polar regions 7#bj round each pole1  we 

may say7 to the extent of something more
 than a foot thick1 enough to  give #a4a
 foot of water over those areas1 or     
#j4jjf of a foot of water if  spread    
over the whole globe1 which would1 in   
reality1 raise the sea-level  by only   
some such undiscoverable difference as  
three-fourths of an inch  or an inch4   
,this1 or the reverse1 which we believe 
might happen any year1  and could       
certainly not be detected without far   
more accurate  observations and         
calculations for the mean sea-level than
 any hitherto  made1 would slacken or   
quicken the earth's rate as a timekeeper
 by one-  tenth of a second per year4#ai
    ,footnote #ai3 ,ibid4    ,i do not  
presume to throw the slightest doubt    
upon the accuracy of any of  the        
calculations made by such distinguished 
mathematicians as those who  have made  
the suggestions ,i have cited4 ,on the  
contrary1 it is necessary  to my        
argument to assume that they are all    
correct4 ,but ,i desire to point  out   

that this seems to be one of the many   
cases in which the admitted  accuracy of
 mathematical process is allowed to     
throw a wholly  inadmissible appearance 
of authority over the results obtained  
by them4  ,mathematics may be compared  
to a mill of exquisite workmanship1     
which  grinds you stuff of any degree of
 fineness2 but1 nevertheless1 what you  
get out depends upon what you put in2   
and as the grandest mill in the  world  
will not extract wheat-flour from       
peascods1 so pages of formulae  will not
 get a definite result out of loose     
data4    ,in the present instance it    
appears to be admitted3--    #a4 ,that  
it is not absolutely certain1 after all1
 whether the moon's mean  motion is     
undergoing acceleration1 or the earth's 
rotation  retardation4#bj ,and yet this 
is the key of the whole position4       
,footnote #bj3 ,it will be understood   
that ,i do not wish to deny that the    
earth's rotation may be undergoing      
retardation4    #b4 ,if the rapidity of 

the earth's rotation is diminishing1 it 
is not  certain how much of that        
retardation is due to tidal friction1   
how much  to meteors1 how much to       
possible excess of melting over         
accumulation of  polar ice1 during the  
period covered by observation1 which    
amounts1 at  the outside1 to not more   
than #b1fjj years4    #c4 ,the effect of
 a different distribution of land and   
water in modifying  the retardation     
caused by tidal friction1 and of        
reducing it1 under some  circumstances1 
to a minimum1 does not appear to be     
taken into account4    #d4 ,during the  
,miocene epoch the polar ice was        
certainly many feet thinner  than it has
 been during1 or since1 the ,glacial    
epoch4 ,sir ,w4 ,thomson  tells us that 
the accumulation of something more than 
a foot of ice  around the poles 7which  
implies the withdrawal of1 say1 an inch 
of water  from the general surface of   
the sea7 will cause the earth to rotate 
quicker by one-tenth of a second per    

annum4 ,it would appear1 therefore1     
that the earth may have been rotating1  
throughout the whole period which  has  
elapsed from the commencement of the    
,glacial epoch down to the  present     
time1 one1 or more1 seconds per annum   
quicker than it rotated  during the     
,miocene epoch4    ,but1 according to   
,sir ,w4 ,thomson's calculation1 tidal  
retardation will  only account for a    
retardation of #bb in a century1 or     
#bb_/ajj 7say #a_/e7  of a second per   
annum4    ,thus1 assuming that the      
accumulation of polar ice since the     
,miocene epoch  has only been sufficient
 to produce ten times the effect of a   
coat of ice  one foot thick1 we shall   
have an accelerating cause which covers 
all the  loss from tidal action1 and    
leaves a balance of #d_/e of a second   
per annum  in the way of acceleration4  
,if tidal retardation can be thus       
checked and overthrown by other         
temporary conditions1 what becomes of   
the confident assertion1 based upon  the

 assumed uniformity of tidal            
retardation1 that ten thousand million  
years ago the earth must have been      
rotating more than twice as fast as at  
present1 and1 therefore1 that we        
geologists are in direct opposition to  
the principles of ,natural ,philosophy  
if we spread geological history  over   
that time8    ,,ii4 ,the second argument
 is thus stated by ,sir ,w4             
,thomson3--,an article1  by myself1     
published in ',macmillan's ,magazine'   
for ,march #ahfb1 on the age  of the    
sun's heat1 explains results of         
investigation into various  questions as
 to possibilities regarding the amount  
of heat that the sun  could have1       
dealing with it as you would with a     
stone1 or a piece of  matter1 only      
taking into account the sun's           
dimensions1 which showed it to  be      
possible that the sun may have already  
illuminated the earth for as  many as   
one hundred million years1 but at the   
same time rendered it  almost certain   

that he had not illuminated the earth   
for five hundred  millions of years4    
,the estimates here are necessarily very
 vague2 but  yet1 vague as they are1 ,i 
do not know that it is possible1 upon   
any  reasonable estimate founded on     
known properties of matter1 to say that 
we  can believe the sun has really      
illuminated the earth for five hundred  
million years4#ba    ,footnote #ba3     
,loc4 cit4 p4 #bj4    ,i do not wish to 
,hansardise ,sir ,william ,thomson by   
laying much stress  on the fact that1   
only fifteen years ago he entertained a 
totally  different view of the origin of
 the sun's heat1 and believed that the  
energy radiated from year to year was   
supplied from year to year--a  doctrine 
which would have suited ,hutton         
perfectly4 ,but the fact that so        
eminent a physical philosopher has1 thus
 recently1 held views opposite to  those
 which he now entertains1 and that he   
confesses his own estimates to  be very 
vague1 justly entitles us to disregard  

those estimates1 if any  distinct facts 
on our side go against them4 ,however1  
,i am not aware that  such facts exist4 
,as ,i have already said1 for anything  
,i know1 one1 two1  or three hundred    
millions of years may serve the needs of
 geologists  perfectly well4    ,,iii4  
,the third line of argument is based    
upon the temperature of the  interior of
 the earth4 ,sir ,w4 ,thomson refers to 
certain investigations  which prove that
 the present thermal condition of the   
interior of the  earth implies either a 
heating of the earth within the last    
#bj1jjj years  of as much as #ajj ,f41  
or a greater heating all over the       
surface at some  time further back than 
#bj1jjj years1 and then proceeds thus3--
    ,now1 are geologists prepared to    
admit that1 at some time within the last
  #bj1jjj years1 there has been all over
 the earth so high a temperature as     
that8 ,i presume not2 no geologist--no  
modern geologist--would for a  moment   
admit the hypothesis that the present   

state of underground heat is  due to a  
heating of the surface at so late a     
period as #bj1jjj years ago4  ,if that  
is not admitted we are driven to a      
greater heat at some time more  than    
#bj1jjj years ago4 ,a greater heating   
all over the surface than #ajj          
,fahrenheit would kill nearly all       
existing plants and animals1 ,i may     
safely say4 ,are modern geologists      
prepared to say that all life was       
killed off the earth #ej1jjj1 #ajj1jjj1 
or #bjj1jjj years ago8 ,for the         
uniformity theory1 the further back the 
time of high surface-temperature  is put
 the better2 but the further back the   
time of heating1 the hotter  it must    
have been4 ,the best for those who draw 
most largely on time is  that which puts
 it furthest back2 and that is the      
theory that the heating  was enough to  
melt the whole4 ,but even if it was     
enough to melt the  whole1 we must still
 admit some limit1 such as fifty million
 years1 one  hundred million years1 or  

two or three hundred million years ago4 
,beyond  that we cannot go4#bb          
,footnote #bb3 ,loc4 cit4 p4 #bd4    ,it
 will be observed that the limit is once
 again of the vaguest1  ranging from    
#ej1jjj1jjj years to #cjj1jjj1jjj4 ,and 
the reply is1 once  more1 that1 for     
anything that can be proved to the      
contrary1 one or two  hundred million   
years might serve the purpose1 even of a
 thoroughgoing  ,huttonian              
uniformitarian1 very well4    ,but if1  
on the other hand1 the #ajj1jjj1jjj or  
#bjj1jjj1jjj years appear to  be        
insufficient for geological purposes1 we
 must closely criticise the  method by  
which the limit is reached4 ,the        
argument is simple enough4  ,assuming   
the earth to be nothing but a cooling   
mass1 the quantity of  heat lost per    
year1 supposing the rate of cooling to  
have been uniform1  multiplied by any   
given number of years1 will be given the
 minimum  temperature that number of    
years ago4    ,but is the earth nothing 

but a cooling mass1 like a hot-water jar
 such  as is used in carriages1 or a    
globe of sandstone1 and has its cooling 
been uniform8 ,an affirmative answer to 
both these questions seems to be        
necessary to the validity of the        
calculations on which ,sir ,w4 ,thomson 
lays so much stress4    ,nevertheless it
 surely may be urged that such          
affirmative answers are  purely         
hypothetical1 and that other            
suppositions have an equal right to     
consideration4    ,for example1 is it   
not possible that1 at the prodigious    
temperature which  would seem to exist  
at #ajj miles below the surface1 all the
 metallic  bases may behave as mercury  
does at a red heat1 when it refuses to  
combine with oxygen2 while1 nearer the  
surface1 and therefore at a lower       
temperature1 they may enter into        
combination 7as mercury does with oxygen
  a few degrees below its               
boiling-point71 and so give rise to a   
heat  totally distinct from that which  

they possess as cooling bodies8 ,and has
  it not also been proved by recent     
researches that the quality of the      
atmosphere may immensely affect its     
permeability to heat2 and1              
consequently1 profoundly modify the rate
 of cooling the globe as a whole8    ,i 
do not think it can be denied that such 
conditions may exist1 and may  so       
greatly affect the supply1 and the loss1
 of terrestrial heat as to  destroy the 
value of any calculations which leave   
them out of sight4    ,my functions as  
your advocate are at an end4 ,i speak   
with more than the  sincerity of a mere 
advocate when ,i express the belief that
 the case  against us has entirely      
broken down4 ,the cry for reform which  
has been  raised without1 is            
superfluous1 inasmuch as we have long   
been reforming  from within1 with all   
needful speed4 ,and the critical        
examination of the  grounds upon which  
the very grave charge of opposition to  
the principles  of ,natural ,philosophy 

has been brought against us1 rather     
shows that we  have exercised a wise    
discrimination in declining1 for the    
present1 to  meddle with our            
foundations4        ,,xi                
,,palaeontology ,,and ,,the ,,doctrine  
,,of ,,evolution    #ahgj    ,it is now 
eight years since1 in the absence of the
 late ,mr4 ,leonard  ,horner1 who then  
presided over us1 it fell to my lot1 as 
one of the  ,secretaries of this        
,society1 to draw up the customary      
,annual ,address4 ,i  availed myself of 
the opportunity to endeavour to take    
stock of that  portion of the science of
 biology which is commonly called       
palaeontology1 as it then existed2 and1 
discussing one after another the        
doctrines held by palaeontologists1 ,i  
put before you the results of my        
attempts to sift the well-established   
from the hypothetical or the  doubtful4 
,permit me briefly to recall to your    
minds what those results  were3--    #a4
 ,the living population of all parts of 

the earth's surface which have  yet been
 examined has undergone a succession of 
changes which1 upon the  whole1 have    
been of a slow and gradual character4   
#b4 ,when the fossil remains which are  
the evidences of these successive       
changes1 as they have occurred in any   
two more or less distant parts of  the  
surface of the earth1 are compared1 they
 exhibit a certain broad and  general   
parallelism4 ,in other words1 certain   
forms of life in one  locality occur in 
the same general order of succession as1
 or are  homotaxial with1 similar forms 
in the other locality4    #c4 ,homotaxis
 is not to be held identical with       
synchronism without  independent        
evidence4 ,it is possible that similar1 
or even identical1  faunae and florae in
 two different localities may be of     
extremely different  ages1 if the term  
age is used in its proper chronological 
sense4 ,i  stated that geographical     
provinces1 or zones1 may have been as   
distinctly marked in the ,palaeozoic    

epoch as at present2 and those          
seemingly sudden appearances of new     
genera and species which we ascribe  to 
new creation1 may be simple results of  
migration4    #d4 ,the opinion that the 
oldest known fossils are the earliest   
forms of  life has no solid foundation4 
#e4 ,if we confine ourselves to         
positively ascertained facts1 the total 
amount of change in the forms of animal 
and vegetable life1 since the  existence
 of such forms is recorded1 is small4   
,when compared with the  lapse of time  
since the first appearance of these     
forms1 the amount of  change is         
wonderfully small4 ,moreover1 in each   
great group of the animal  and vegetable
 kingdoms1 there are certain forms which
 ,i termed ,,persistent  ,,types1 which 
have remained1 with but very little     
apparent change1 from  their first      
appearance to the present time4    #f4  
,in answer to the question ,what1 then1 
does an impartial survey of the         
positively ascertained truths of        

palaeontology testify in relation to the
  common doctrines of progressive       
modification1 which suppose that        
modification to have taken place by a   
necessary progress from more to  less   
embryonic forms1 from more to less      
generalised types1 within the  limits of
 the period represented by the          
fossiliferous rocks8 ,i reply1  ,it     
negatives these doctrines2 for it either
 shows us no evidence of such           
modification1 or demonstrates such      
modification as has occurred to have    
been very slight2 and1 as to the nature 
of that modification1 it yields  no     
evidence whatsoever that the earlier    
members of any long-continued  group    
were more generalised in structure than 
the later ones4    ,i think that ,i     
cannot employ my last opportunity of    
addressing you1  officially1 more       
properly--,i may say more               
dutifully--than in revising  these old  
judgments with such help as further     
knowledge and reflection1  and an       

extreme desire to get at the truth1 may 
afford me4    #a4 ,with respect to the  
first proposition1 ,i may remark that   
whatever may  be the case among the     
physical geologists1 catastrophic       
palaeontologists  are practically       
extinct4 ,it is now no part of          
recognised geological  doctrine that the
 species of one formation all died out  
and were replaced  by a brand-new set in
 the next formation4 ,on the contrary1  
it is  generally1 if not universally1   
agreed that the succession of life has  
been the result of a slow and gradual   
replacement of species by species2  and 
that all appearances of abruptness of   
change are due to breaks in the  series 
of deposits1 or other changes in        
physical conditions4 ,the  continuity of
 living forms has been unbroken from the
 earliest times to  the present day4    
#b1 #c4 ,the use of the word homotaxis  
instead of synchronism has not1  so far 
as ,i know1 found much favour in the    
eyes of geologists4 ,i hope1  therefore1

 that it is a love for scientific       
caution1 and not mere  personal         
affection for a bantling of my own1     
which leads me still to  think that the 
change of phrase is of importance1 and  
that the sooner it  is made1 the sooner 
shall we get rid of a number of pitfalls
 which beset  the reasoner upon the     
facts and theories of geology4    ,one  
of the latest pieces of foreign         
intelligence which has reached us is    
the information that the ,austrian      
geologists have1 at last1 succumbed to  
the weighty evidence which ,m4 ,barrande
 has accumulated1 and have admitted  the
 doctrine of colonies4 ,but the         
admission of the doctrine of colonies   
implies the further admission that even 
identity of organic remains is no  proof
 of the synchronism of the deposits     
which contain them4    #d4 ,the         
discussions touching the ,eozoon1 which 
commenced in #ahfd1 have  abundantly    
justified the fourth proposition4 ,in   
#ahfb1 the oldest record  of life was in

 the ,cambrian rocks2 but if the ,eozoon
 be1 as ,principal  ,dawson and ,dr4    
,carpenter have shown so much reason for
 believing1 the  remains of a living    
being1 the discovery of its true nature 
carried life  back to a period which1 as
 ,sir ,william ,logan has observed1 is  
as remote  from that during which the   
,cambrian rocks were deposited1 as the  
,cambrian  epoch itself is from the     
tertiaries4 ,in other words1 the        
ascertained  duration of life upon the  
globe was nearly doubled at a stroke4   
#e4 ,the significance of persistent     
types1 and of the small amount of       
change which has taken place even in    
those forms which can be shown to  have 
been modified1 becomes greater and      
greater in my eyes1 the longer ,i       
occupy myself with the biology of the   
past4    ,consider how long a time has  
elapsed since the ,miocene epoch4 ,yet1 
at  that time there is reason to believe
 that every important group in every    
order of the ,mammalia was represented4 

,even the comparatively scanty  ,eocene 
fauna yields examples of the orders     
,cheiroptera1 ,insectivora1  ,rodentia1 
and ,perissodactyla2 of ,artiodactyla   
under both the  ,ruminant and the       
,porcine modifications2 of ,caranivora1 
,cetacea1 and  ,marsupialia4    ,or1 if 
we go back to the older half of the     
,mesozoic epoch1 how truly  surprising  
it is to find every order of the        
,reptilia1 except the  ,ophidia1        
represented2 while some groups1 such as 
the ,ornithoseclida  and the            
,pterosauria1 more specialised than any 
which now exist1  abounded4    ,there is
 one division of the ,amphibia which    
offers especially important  evidence   
upon this point1 inasmuch as it bridges 
over the gap between the  ,mesozoic and 
the ,palaeozoic formations 7often       
supposed to be of such  prodigious      
magnitude71 extending1 as it does1 from 
the bottom of the  ,carboniferous series
 to the top of the ,trias1 if not into  
the ,lias4 ,i  refer to the             

,labyrinthodonts4 ,as the ,address of   
#ahfb was passing through  the press1 ,i
 was able to mention1 in a note1 the    
discovery of a large  ,labyrinthodont1  
with well-ossified vertebrae1 in the    
,edinburgh coal-field4  ,since that time
 eight or ten distinct genera of        
,labyrinthodonts have been  discovered  
in the ,carboniferous rocks of ,england1
 ,scotland1 and ,ireland1  not to       
mention the ,american forms described by
 ,principal ,dawson and  ,professor     
,cope4 ,so that1 at the present time1   
the ,labyrinthodont ,fauna of  the      
,carboniferous rocks is more extensive  
and diversified than that of  the       
,trias1 while its chief types1 so far as
 osteology enables us to  judge1 are    
quite as highly organised4 ,thus it is  
certain that a  comparatively highly    
organised vertebrate type1 such as that 
of the  ,labyrinthodonts1 is capable of 
persisting1 with no considerable change1
  through the period represented by the 
vast deposits which constitute the      

,carboniferous1 the ,permian1 and the   
,triassic formations4    ,the very      
remarkable results which have been      
brought to light by the  sounding and   
dredging operations1 which have been    
carried on with such  remarkable success
 by the expeditions sent out by our own1
 the ,american1  and the ,swedish       
,governments1 under the supervision of  
able naturalists1  have a bearing in the
 same direction4 ,these investigations  
have  demonstrated the existence1 at    
great depths in the ocean1 of living    
animals in some cases identical with1 in
 others very similar to1 those  which   
are found fossilised in the white chalk4
 ,the ,globigerinoe1  ,cyatholiths1     
,coccospheres1 ,discoliths in the one   
are absolutely identical  with those in 
the other2 there are identical1 or      
closely analogous1  species of ,sponges1
 ,echinoderms1 and ,brachiopods4 ,off   
the coast of  ,portugal1 there now lives
 a species of ,beryx1 which1 doubtless1 
leaves  its bones and scales here and   

there in the ,atlantic ooze1 as its     
predecessor left its spoils in the mud  
of the sea of the ,cretaceous  epoch4   
,many years ago#a ,i ventured to speak  
of the ,atlantic mud as modern  chalk1  
and ,i know of no fact inconsistent with
 the view which ,professor  ,wyville    
,thomson has advocated1 that the modern 
chalk is not only the  lineal descendant
 of the ancient chalk1 but that it      
remains1 so to speak1  in the possession
 of the ancestral estate2 and that from 
the ,cretaceous  period 7if not much    
earlier7 to the present day1 the deep   
sea has covered  a large part of what is
 now the area of the ,atlantic4 ,but if 
,globigerina1 and ,terebratula          
caput-serpentis and ,beryx1 not to      
mention other forms of animals and of   
plants1 thus bridge over the  interval  
between the present and the ,mesozoic   
periods1 is it possible  that the       
majority of other living things         
underwent a sea-change into  something  
new and strange all at once8            

,footnote #a3 ,see an article in the    
,saturday ,review1 for #aheh1 on        
,chalk1 ,ancient and ,modern4    #f4    
,thus far ,i have endeavoured to expand 
and to enforce by fresh  arguments1 but 
not to modify in any important respect1 
the ideas  submitted to you on a former 
occasion4 ,but when ,i come to the      
propositions touching progressive       
modification1 it appears to me1 with    
the help of the new light which has     
broken from various quarters1 that      
there is much ground for softening the  
somewhat ,brutus-like severity with     
which1 in #ahfb1 ,i dealt with a        
doctrine1 for the truth of which ,i     
should  have been glad enough to be able
 to find a good foundation4 ,so far1    
indeed1 as the ,invertebrata and the    
lower ,vertebrata are concerned1  the   
facts and the conclusions which are to  
be drawn from them appear to  me to     
remain what they were4 ,for anything    
that1 as yet1 appears to the  contrary1 
the earliest known ,marsupials may have 

been as highly organised  as their      
living congeners2 the ,permian lizards  
show no signs of  inferiority to those  
of the present day2 the ,labyrinthodonts
 cannot be  placed below the living     
,salamander and ,triton2 the ,devonian  
,ganoids are  closely related to        
,polypterus and to ,lepidosiren4    ,but
 when we turn to the higher ,vertebrata1
 the results of recent  investigations1 
however we may sift and criticise them1 
seem to me to  leave a clear balance in 
favour of the doctrine of the evolution 
of  living forms one from another4      
,nevertheless1 in discussing this       
question1  it is very necessary to      
discriminate carefully between the      
different  kinds of evidence from fossil
 remains which are brought forward in   
favour  of evolution4    ,every fossil  
which takes an intermediate place       
between forms of life  already known1   
may be said1 so far as it is            
intermediate1 to be evidence  in favour 
of evolution1 inasmuch as it shows a    

possible road by which  evolution may   
have taken place4 ,but the mere         
discovery of such a form  does not1 in  
itself1 prove that evolution took place 
by and through it1  nor does it         
constitute more than presumptive        
evidence in favour of  evolution in     
general4 ,suppose ,a1 ,b1 ,c to be three
 forms1 while ,b is  intermediate in    
structure between ,a and ,c4 ,then the  
doctrine of evolution  offers four      
possible alternatives4 ,a may have      
become ,c by way of ,b2 or ,c  may have 
become ,a by way of ,b2 or ,a and ,c may
 be independent  modifications of ,b2 or
 ,a1 ,b1 and ,c may be independent      
modifications of  some unknown ,d4 ,take
 the case of the ,pigs1 the             
,anoplothcridoe1 and the  ,ruminants4   
,the ,anoplothcridoe are intermediate   
between the first and  the last2 but    
this does not tell us whether the       
,ruminants have come from  the ,pigs1 or
 the ,pigs from ,ruminants1 or both from
 ,anoplothcridoe1 or  whether ,pigs1    

,ruminants1 and ,anoplotlicridoe alike  
may not have  diverged from some common 
stock4    ,but if it can be shown that  
,a1 ,b1 and ,c exhibit successive stages
 in the  degree of modification1 or     
specialisation1 of the same type2 and   
if1  further1 it can be proved that they
 occur in successively newer deposits1  
,a being in the oldest and ,c in the    
newest1 then the intermediate  character
 of ,b has quite another importance1 and
 ,i should accept it1  without          
hesitation1 as a link in the genealogy  
of ,c4 ,i should consider  the burden of
 proof to be thrown upon any one who    
denied ,c to have been  derived from ,a 
by way of ,b1 or in some closely        
analogous fashion2 for it  is always    
probable that one may not hit upon the  
exact line of filiation1  and1 in       
dealing with fossils1 may mistake uncles
 and nephews for fathers  and sons4     
,i think it necessary to distinguish    
between the former and the latter       
classes of intermediate forms1 as       

intercalary types and linear types4     
,when ,i apply the former term1 ,i      
merely mean to say that as a matter of  
fact1 the form ,b1 so named1 is         
intermediate between the others1 in the 
sense in which the ,anoplotherium is    
intermediate between the ,pigs and  the 
,ruminants--without either affirming1 or
 denying1 any direct genetic  relation  
between the three forms involved4 ,when 
,i apply the latter term1  on the other 
hand1 ,i mean to express the opinion    
that the forms ,a1 ,b1 and  ,c          
constitute a line of descent1 and that  
,b is thus part of the lineage of  ,c4  
,from the time when ,cuvier's wonderful 
researches upon the extinct ,mammals  of
 the ,paris gypsum first made           
intercalary types known1 and caused them
  to be recognised as such1 the number  
of such forms has steadily increased    
among the higher ,mammalia4 ,not only do
 we now know numerous intercalary       
forins of ,ungulata1 but ,m4 ,gaudry's  
great monograph upon the fossils of     

,pikermi 7which strikes me as one of the
 most perfect pieces of                 
palaeontological work ,i have seen for a
 long time7 shows us1 among the         
,primates1 ,mesopithecus as an          
intercalary form between the            
,semnopitheci and the ,macaci2 and among
 the ,carnivora1 ,hyoenictis  and       
,ictitherium as intercalary1 or1        
perhaps1 linear types between the       
,viverridoe and the ,hyoenidoe4         
,hardly any order of the higher         
,mammalia stands so apparently separate 
and isolated from the rest as that of   
the ,cetacea2 though a careful          
consideration of the structure of the   
pinnipede ,carnivora1 or ,seals1  shows1
 in them1 many an approximation towards 
the still more completely  marine       
mammals4 ,the extinct ,zeuglodon1       
however1 presents us with an            
intercalary form between the type of the
 ,seals and that of the ,whales4  ,the  
skull of this great ,eocene sea-monster1
 in fact1 shows by the narrow  and      

prolonged interorbital region2 the      
extensive union of the parietal  bones  
in a sagittal suture2 the well-developed
 nasal bones2 the distinct  and large   
incisors implanted in premaxillary      
bones1 which take a full  share in      
bounding the fore part of the gape2 the 
two-fanged molar teeth  with triangular 
and serrated crowns1 not exceeding five 
on each side in  each jaw2 and the      
existence of a deciduous dentition--its 
close relation  with the ,seals4 ,while1
 on the other hand1 the produced rostral
 form of  the snout1 the long symphysis1
 and the low coronary process of the    
mandible are approximations to the      
cetacean form of those parts4    ,the   
scapula resembles that of the cetacean  
,hyperoodon1 but the supra-  spinous    
fossa is larger and more seal-like2 as  
is the humerus1 which  differs from that
 of the ,cetacea in presenting true     
articular surfaces  for the free        
jointing of the bones of the fore-arm4  
,in the apparently  complete absence of 

hinder limbs1 and in the characters of  
the vertebral  column1 the ,zeuglodon   
lies on the cetacean side of the        
boundary line2  so that upon the whole1 
the ,zeuglodonts1 transitional as they  
are1 are  conveniently retained in the  
cetacean order4 ,and the publication1 in
  #ahfd1 of ,m4 ,van ,beneden's memoir  
on the ,miocene and ,pliocene           
,squalodon1  furnished much better means
 than anatomists previously possessed of
  fitting in another link of the chain  
which connects the existing  ,cetacea   
with ,zeuglodon4 ,the teeth are much    
more numerous1 although  the molars     
exhibit the zeuglodont double fang2 the 
nasal bones are very  short1 and the    
upper surface of the rostrum presents   
the groove1 filled  up during life by   
the prolongation of the ethmoidal       
cartilage1 which is  so characteristic  
of the majority of the ,cetacea4    ,it 
appears to me that1 just as among the   
existing ,carnivora1 the  walruses and  
the eared seals are intercalary forms   

between the fissipede  ,carnivora and   
the ordinary seals1 so the ,zeuglodonts 
are intercalary  between the ,carnivora1
 as a whole1 and the ,cetacea4 ,whether 
the  ,zeuglodonts are also linear types 
in their relation to these two groups   
cannot be ascertained1 until we have    
more definite knowledge than we  possess
 at present1 respecting the relations in
 time of the ,carnivora  and ,cetacea4  
,thus far we have been concerned with   
the intercalary types which occupy  the 
intervals between ,families or ,orders  
of the same class2 but the              
investigations which have been carried  
on by ,professor ,gegenbaur1  ,professor
 ,cope1 and myself into the structure   
and relations of the  extinct reptilian 
forms of the ,ornithoscelida 7or        
,dinosauria and  ,compsognatha7 have    
brought to light the existence of       
intercalary forms  between what have    
hitherto been always regarded as very   
distinct classes  of the vertebrate     
sub-kingdom1 namely ,reptilia and ,aves4

 ,whatever  inferences may1 or may not1 
be drawn from the fact1 it is now an    
established truth that1 in many of these
 ,ornithoscelida1 the hind limbs  and   
the pelvis are much more similar to     
those of ,birds than they are to  those 
of ,reptiles1 and that these            
,bird-reptiles1 or ,reptile-birds1 were 
more or less completely bipedal4        
,when ,i addressed you in #ahfb1 ,i     
should have been bold indeed had ,i     
suggested that palaeontology would      
before long show us the possibility of  
a direct transition from the type of the
 lizard to that of the ostrich4  ,at the
 present moment1 we have1 in the        
,ornithoscelida1 the intercalary  type1 
which proves that transition to be      
something more than a  possibility2 but 
it is very doubtful whether any of the  
genera of  ,ornithoscelida with which we
 are at present acquainted are the      
actual  linear types by which the       
transition from the lizard to the bird  
was  effected4 ,these1 very probably1   

are still hidden from us in the older   
formations4    ,let us now endeavour to 
find some cases of true linear types1 or
 forms  which are intermediate between  
others because they stand in a direct   
genetic relation to them4 ,it is no easy
 matter to find clear and  unmistakable 
evidence of filiation among fossil      
animals2 for1 in order  that such       
evidence should be quite satisfactory1  
it is necessary that we  should be      
acquainted with all the most important  
features of the  organisation of the    
animals which are supposed to be thus   
related1 and  not merely with the       
fragments upon which the genera and     
species of the  palaeontologist are so  
often based4 ,m4 ,gaudry has arranged   
the species of  ,hyoenidoe1             
,proboscidea1 ,rhinocerotidoe1 and      
,equidoe in their order of  filiation   
from their earliest appearance in the   
,miocene epoch to the  present time1 and
 ,professor ,rtimeyer has drawn up      
similar schemes for  the ,oxen and other

 ,ungulata--with what1 ,i am disposed to
 think1 is a  fair and probable         
approximation to the order of nature4   
,but1 as no one is  better aware than   
these two learned1 acute1 and           
philosophical biologists1  all such     
arrangements must be regarded as        
provisional1 except in those  cases in  
which1 by a fortunate accident1 large   
series of remains are  obtainable from a
 thick and widespread series of         
deposits4 ,it is easy to  accumulate    
probabilities--hard to make out some    
particular case in such a  way that it  
will stand rigorous criticism4    ,after
 much search1 however1 ,i think that    
such a case is to be made out in  favour
 of the pedigree of the ,horses4    ,the
 genus ,equus is represented as far back
 as the latter part of the  ,miocene    
epoch2 but in deposits belonging to the 
middle of that epoch its  place is taken
 by two other genera1 ,hipparion and    
,anchitherium2#b  and1 in the lowest    
,miocene and upper ,eocene1 only the    

last genus occurs4  ,a species of       
,anchitherium was referred by ,cuvier to
 the ,paloeotheria  under the name of   
,p4 aurelianense4 ,the grinding-teeth   
are in fact very  similar in shape and  
in pattern1 and in the absence of any   
thick layer of  cement1 to those of some
 species of ,paloeotherium1 especially  
,cuvier's  ,paloeotherium minus1 which  
has been formed into a separate genus1  
,plagiolophus1 by ,pomel4 ,but in the   
fact that there are only six full-      
sized grinders in the lower jaw1 the    
first premolar being very small2  that  
the anterior grinders are as large as1  
or rather larger than1 the  posterior   
ones2 that the second premolar has an   
anterior prolongation2  and that the    
posterior molar of the lower jaw has1 as
 ,cuvier pointed out1  a posterior lobe 
of much smaller size and different form1
 the dentition  of ,anchitherium departs
 from the type of the ,paloeotherium1   
and  approaches that of the ,horse4     
,footnote #b3 ,hermann von ,meyer gave  

the name of ,anchitherium to ,a4        
,ezquerroe2 and in his paper on the     
subject he takes great pains to         
distinguish the latter as the type of a 
new genus1 from ,cuvier's               
,paloeotherium d',orlans4 ,but it is    
precisely the ,paloeotherium  d',orlans 
which is the type of ,christol's genus  
,hipparitherium2 and  thus1 though      
,hipparitherium is of later date than   
,anchitherium1 it  seemed to me to have 
a sort of equitable right to recognition
 when this  ,address was written4 ,on   
the whole1 however1 it seems most       
convenient to  adopt ,anchitherium4     
,again1 the skeleton of ,anchitherium is
 extremely equine4 ,m4 ,christol  goes  
so far as to say that the description of
 the bones of the horse1 or  the ass1   
current in veterinary works1 would fit  
those of ,anchitherium4  ,and1 in a     
general way1 this may be true enough2   
but there are some most  important      
differences1 which1 indeed1 are justly  
indicated by the same  careful observer4

 ,thus the ulna is complete throughout1 
and its shaft is  not a mere rudiment1  
fused into one bone with the radius4    
,there are three  toes1 one large in the
 middle and one small on each side4 ,the
 femur is  quite like that of a horse1  
and has the characteristic fossa above  
the  external condyle4 ,in the ,british 
,museum there is a most instructive     
specimen of the leg-bones1 showing that 
the fibula was represented by the       
external malleolus and by a flat tongue 
of bone1 which extends up from it  on   
the outer side of the tibia1 and is     
closely ankylosed with the latter       
bone4#c ,the hind toes are three1 like  
those of the fore leg2 and the  middle  
metatarsal bone is much less compressed 
from side to side than  that of the     
horse4    ,footnote #c3 ,i am indebted  
to ,m4 ,gervais for a specimen which    
indicates  that the fibula was complete1
 at any rate1 in some cases2 and for a  
very  interesting ramps of a mandible1  
which shows that1 as in the             

,paloeotheria1 the hindermost milk-molar
 of the lower jaw was devoid of  the    
posterior lobe which exists in the      
hindermost true molar4    ,in the       
,hipparion1 the teeth nearly resemble   
those of the ,horses1 though  the crowns
 of the grinders are not so long2 like  
those of the ,horses1  they are         
abundantly coated with cement4 ,the     
shaft of the ulna is reduced  to a mere 
style1 ankylosed throughout nearly its  
whole length with the  radius1 and      
appearing to be little more than a ridge
 on the surface of  the latter bone     
until it is carefully examined4 ,the    
front toes are still  three1 but the    
outer ones are more slender than in     
,anchitherium1 and  their hoofs smaller 
in proportion to that of the middle toe2
 they are1 in  fact1 reduced to mere    
dew-claws1 and do not touch the ground4 
,in the leg1  the distal end of the     
fibula is so completely united with the 
tibia that  it appears to be a mere     
process of the latter bone1 as in the   

,horses4    ,in ,equus1 finally1 the    
crowns of the grinding-teeth become     
longer1 and  their patterns are slightly
 modified2 the middle of the shaft of   
the ulna  usually vanishes1 and its     
proximal and distal ends ankylose with  
the  radius4 ,the phalanges of the two  
outer toes in each foot disappear1 their
  metacarpal and metatarsal bones being 
left as the splints4    ,the ,hipparion 
has large depressions on the face in    
front of the orbits1  like those for the
 larmiers of many ruminants2 but traces 
of these are  to be seen in some of the 
fossil horses from the ,sewalik ,hills2 
and1 as  ,leidy's recent researches     
show1 they are preserved in             
,anchitherium4    ,when we consider     
these facts1 and the further            
circumstance that the  ,hipparions1 the 
remains of which have been collected in 
immense numbers1  were subject1 as ,m4  
,gaudry and others have pointed out1 to 
a great range  of variation1 it appears 
to me impossible to resist the          

conclusion that  the types of the       
,anchitherium1 of the ,hipparion1 and of
 the ancient  ,horses constitute the    
lineage of the modern ,horses1 the      
,hipparion being  the intermediate stage
 between the other two1 and answering to
 ,b in my  former illustration4    ,the 
process by which the ,anchitherium has  
been converted into ,equus  is one of   
specialisation1 or of more and more     
complete deviation from  what might be  
called the average form of an ungulate  
mammal4 ,in the  ,horses1 the reduction 
of some parts of the limbs1 together    
with the  special modification of those 
which are left1 is carried to a greater 
extent than in any other hoofed mammals4
 ,the reduction is less and the         
specialisation is less in the           
,hipparion1 and still less in the       
,anchitherium2 but yet1 as compared with
 other mammals1 the reduction  and      
specialisation of parts in the          
,anchitherium remain great4    ,is it   
not probable then1 that1 just as in the 

,miocene epoch1 we find an  ancestral   
equine form less modified than ,equus1  
so1 if we go back to  the ,eocene epoch1
 we shall find some quadruped related to
 the  ,anchitherium1 as ,hipparion is   
related to ,equus1 and consequently     
departing less from the average form8   
,i think that this desideratum is very  
nearly1 if not quite1 supplied by       
,plagiolophus1 remains of which occur   
abundantly in some parts of the  ,upper 
and ,middle ,eocene formations4 ,the    
patterns of the grinding-teeth of       
,plagiolophus are similar to those of   
,anchitherium1 and their crowns  are as 
thinly covered with cement2 but the     
grinders diminish in size  forwards1 and
 the last lower molar has a large hind  
lobe1 convex outwards  and concave      
inwards1 as in ,palueotherium4 ,the ulna
 is complete and much  larger than in   
any of the ,equidoe1 while it is more   
slender than in  most of the true       
,paloeotheria2 it is fixedly united1 but
 not ankylosed1  with the radius4 ,there

 are three toes in the fore limb1 the   
outer ones  being slender1 but less     
attenuated than in the ,equidoe4 ,the   
femur is  more like that of the         
,paloeotheria than that of the horse1   
and has only  a small depression above  
its outer condyle in the place of the   
great  fossa which is so obvious in the 
,equidoe4 ,the fibula is distinct1 but  
very slender1 and its distal end is     
ankylosed with the tibia4 ,there are    
three toes on the hind foot having      
similar proportions to those on the     
fore foot4 ,the principal metacarpal and
 metatarsal bones are flatter than  they
 are in any of the ,equidoe2 and the    
metacarpal bones are longer  than the   
metatarsals1 as in the ,paloeotheria4   
,in its general form1 ,plagiolophus     
resembles a very small and slender      
horse1#d and is totally unlike the      
reluctant1 pig-like creature depicted   
in ,cuvier's restoration of his         
,paloeotherium minus in the ,ossemens   
,fossiles4    ,footnote #d3 ,such1 at   

least1 is the conclusion suggested by   
the  proportions of the skeleton figured
 by ,cuvier and ,de ,blainville2 but    
perhaps something between a ,horse and  
an ,agouti would be nearest the  mark4  
,it would be hazardous to say that      
,plagiolophus is the exact radical  form
 of the ,equine quadrupeds2 but ,i do   
not think there can be any  reasonable  
doubt that the latter animals have      
resulted from the  modification of some 
quadruped similar to ,plagiolophus4     
,we have thus arrived at the ,middle    
,eocene formation1 and yet have traced  
back the ,horses only to a three-toed   
stock2 but these three-toed forms1  no  
less than the ,equine quadrupeds        
themselves1 present rudiments of the    
two other toes which appertain to what  
,i have termed the average  quadruped4  
,if the expectation raised by the       
splints of the ,horses that1  in some   
ancestor of the ,horses1 these splints  
would be found to be  complete digits1  
has been verified1 we are furnished with

 very strong  reasons for looking for a 
no less complete verification of the    
expectation that the three-toed         
,plagiolophus-like avus of the horse    
must have had a five-toed atavus at some
 earlier period4    ,no such five-toed  
atavus1 however1 has yet made its       
appearance among  the few middle and    
older ,eocene ,mammalia which are known4
    ,another series of closely          
affiliated forms1 though the evidence   
they  afford is perhaps less complete   
than that of the ,equine series1 is     
presented to us by the ,dichobune of the
 ,eocene epoch1 the  ,cainotherium of   
the ,miocene1 and the ,tragulidoe1 or   
so-called ,musk-  deer1 of the present  
day4    ,the ,tragulidoe2 have no       
incisors in the upper jaw1 and only six 
grinding-teeth on each side of each jaw2
 while the canine is moved up to  the   
outer incisor1 and there is a diastema  
in the lower jaw4 ,there are  four      
complete toes on the hind foot1 but the 
middle metatarsals usually  become1     

sooner or later1 ankylosed into a cannon
 bone4 ,the navicular and  the cuboid   
unite1 and the distal end of the fibula 
is ankylosed with the  tibia4    ,in    
,cainotherium and ,dichobune the upper  
incisors are fully developed4  ,there   
are seven grinders2 the teeth form a    
continuous series without a  diastema4  
,the metatarsals1 the navicular and     
cuboid1 and the distal end  of the      
fibula1 remain free4 ,in the            
,cainotherium1 also1 the second         
metacarpal is developed1 but is much    
shorter than the third1 while the  fifth
 is absent or rudimentary4 ,in this     
respect it resembles  ,anoplotherium    
secundarium4 ,this circumstance1 and the
 peculiar pattern  of the upper molars  
in ,cainotherium1 lead me to hesitate in
 considering  it as the actual ancestor 
of the modern ,tragulidoe4 ,if          
,dichobune has  a fore-toed fore foot   
7though ,i am inclined to suspect that  
it resembles  ,cainotherium71 it will be
 a better representative of the oldest  

forms  of the ,traguline series2 but    
,dichobune occurs in the ,middle        
,eocene1 and  is1 in fact1 the oldest   
known artiodactyle mammal4 ,where1 then1
 must we  look for its five-toed        
ancestor8    ,if we follow down other   
lines of recent and tertiary ,ungulata1 
the same  question presents itself4 ,the
 ,pigs are traceable back through the   
,miocene  epoch to the ,upper ,eocene1  
where they appear in the two well-marked
 forms  of ,hyopopotamus and            
,choeropotamus2 but ,hyopotamus appears 
to have  had only two toes4    ,again1  
all the great groups of the ,ruminants1 
the ,bovidoe1 ,antilopidoe1             
,camelopardalidoe1 and ,cervidoe1 are   
represented in the ,miocene epoch1  and 
so are the ,camels4 ,the ,upper ,eocene 
,anoplotherium1 which is  intercalary   
between the ,pigs and the ,tragulidoe1  
has only two1 or1 at  most1 three toes4 
,among the scanty mammals of the ,lower 
,eocene formation  we have the          
perissodactyle ,ungulata represented by 

,coryphodon1  ,hyracotherium1 and       
,pliolophus4 ,suppose for a moment1 for 
the sake of  following out the argument1
 that ,pliolophus represents the primary
  stock of the ,perissodactyles1 and    
,dichobune that of the ,artiodactyles   
7though ,i am far from saying that such 
is the case71 then we find1 in the      
earliest fauna of the ,eocene epoch to  
which our investigations carry us1  the 
two divisions of the ,ungulata          
completely differentiated1 and no  trace
 of any common stock of both1 or of     
five-toed predecessors to  either4 ,with
 the case of the ,horses before us1     
justifying a belief in the  production  
of new animal forms by modification of  
old ones1 ,i see no  escape from the    
necessity of seeking for these ancestors
 of the  ,ungulata beyond the limits of 
the ,tertiary formations4    ,i could as
 soon admit special creation1 at once1  
as suppose that the  ,perissodactyles   
and ,artiodactyles had no five-toed     
ancestors4 ,and when we  consider how   

large a portion of the ,tertiary period 
elapsed before  ,anchitherium was       
converted into ,equus1 it is difficult  
to escape the  conclusion that a large  
proportion of time anterior to the      
,tertiary  period must have been        
expended in converting the common stock 
of the  ,ungulata into ,perissodactyles 
and ,artiodactyles4    ,the same moral  
is inculcated by the study of every     
other order of  ,tertiary monodelphous  
,mammalia4 ,each of these orders is     
represented in  the ,miocene epoch3 the 
,eocene formation1 as ,i have already   
said1 contains  ,cheiroptera1           
,insectivora1 ,rodentia1 ,ungulata1     
,carnivora1 and ,cetacea4  ,but the     
,cheiroptera are extreme modifications  
of the ,insectivora1  just as the       
,cetacea are extreme modifications of   
the ,carnivorous type2  and therefore it
 is to my mind incredible that          
monodelphous ,insectivora  and          
,carnivora should not have been         
abundantly developed1 along with        

,ungulata1 in the ,mesozoic epoch4 ,but 
if this be the case1 how much  further  
back must we go to find the common stock
 of the monodelphous  ,mammalia8 ,as to 
the ,didelphia1 if we may trust the     
evidence which  seems to be afforded by 
their very scanty remains1 a            
,hypsiprymnoid form  existed at the     
epoch of the ,trias1 contemporaneously  
with a ,carnivorous  form4 ,at the epoch
 of the ,trias1 therefore1 the          
,marsupialia must have  already existed 
long enough to have become              
differentiated into  carnivorous and    
herbivorous forms4 ,but the ,monotremata
 are lower forms  than the ,didelphia   
which last are intercalary between the  
,ornithodelphia and the ,monodelphia4   
,to what point of the ,palaeozoic       
epoch1 then1 must we1 upon any rational 
estimate1 relegate the origin of  the   
,monotremata8    ,the investigation of  
the occurrence of the classes and of the
 orders of  the ,sauropsida in time     
points in exactly the same direction4   

,if1 as  there is great reason to       
believe1 true ,birds existed in the     
,triassic  epoch1 the ornithoscelidous  
forms by which ,reptiles passed into    
,birds  must have preceded them4 ,in    
fact there is1 even at present1         
considerable  ground for suspecting the 
existence of ,dinosauria in the ,permian
  formations2 but1 in that case1 lizards
 must be of still earlier date4 ,and  if
 the very small differences which are   
observable between the  ,crocodilia of  
the older ,mesozoic formations and those
 of the present  day furnish any sort of
 approximation towards an estimate of   
the average  rate of change among the   
,sauropsida1 it is almost appalling to  
reflect  how far back in ,palaeozoic    
times we must go1 before we can hope to 
arrive  at that common stock from which 
the ,crocodilia1 ,lacertilia1           
,ornithoscelida1 and ,plesiosauria1     
which had attained so great a           
development in the ,triassic epoch1 must
 have been derived4    ,the ,amphibia   

and ,pisces tell the same story4 ,there 
is not a single  class of vertebrated   
animals which1 when it first appears1 is
 represented  by analogues of the lowest
 known members of the same class4       
,therefore1 if  there is any truth in   
the doctrine of evolution1 every class  
must be  vastly older than the first    
record of its appearance upon the       
surface of  the globe4 ,but if          
considerations of this kind compel us to
 place the  origin of vertebrated       
animals at a period sufficiently distant
 from the  ,upper ,silurian1 in which   
the first ,elasmobranchs and ,ganoids   
occur1 to  allow of the evolution of    
such fishes as these from a ,vertebrate 
as  simple as the ,amphioxus1 ,i can    
only repeat that it is appalling to     
speculate upon the extent to which that 
origin must have preceded the  epoch of 
the first recorded appearance of        
vertebrate life4      ,such is the      
further commentary which ,i have to     
offer upon the statement  of the chief  

results of palaeontology which ,i       
formerly ventured to lay  before you4   
,but the growth of knowledge in the     
interval makes me conscious of an       
omission of considerable moment in that 
statement1 inasmuch as it  contains no  
reference to the bearings of            
palaeontology upon the theory of  the   
distribution of life2 nor takes note of 
the remarkable manner in  which the     
facts of distribution1 in present and   
past times1 accord with  the doctrine of
 evolution1 especially in regard to land
 animals4    ,that connection between   
palaeontology and geology and the       
present  distribution of terrestrial    
animals1 which so strikingly impressed  
,mr4  ,darwin1 thirty years ago1 as to  
lead him to speak of a law of succession
  of types1 and of the wonderful        
relationship on the same continent      
between the dead and the living1 has    
recently received much elucidation  from
 the researches of ,gaudry1 of          
,rutimeyer1 of ,leidy1 and of ,alphonse 

,milne-,edwards1 taken in connection    
with the earlier labours of our         
lamented colleague ,falconer2 and it has
 been instructively discussed in  the   
thoughtful and ingenious work of ,mr4   
,andrew ,murray ,on the  ,geographical  
,distribution of ,mammals4#e            
,footnote #e3 ,the paper ,on the ,form  
and ,distribution of the ,landtracts    
during the ,secondary and ,tertiary     
,periods respectively2 and on the       
,effect  upon ,animal ,life which great 
,changes in ,geographical ,configuration
 have  probably produced1 by ,mr4       
,searles ,v4 ,wood1 jun41 which was     
published in  the ,philosophical        
,magazine1 in #ahfb1 was unknown to me  
when this  ,address was written4 ,it is 
well worthy of the most careful study4  
,i propose to lay before you1 as briefly
 as ,i can1 the ideas to which a  long  
consideration of the subject has given  
rise in my mind4    ,if the doctrine of 
evolution is sound1 one of its immediate
 consequences  clearly is1 that the     

present distribution of life upon the   
globe is the  product of two factors1   
the one being the distribution which    
obtained in  the immediately preceding  
epoch1 and the other the character and  
the  extent of the changes which have   
taken place in physical geography       
between the one epoch and the other2 or1
 to put the matter in another  way1 the 
,fauna and ,flora of any given area1 in 
any given epoch1 can  consist only of   
such forms of life as are directly      
descended from those  which constituted 
the ,fauna and ,flora of the same area  
in the immediately  preceding epoch1    
unless the physical geography 7under    
which ,i include  climatal conditions7  
of the area has been so altered as to   
give rise to  immigration of living     
forms from some other area4    ,the     
evolutionist1 therefore1 is bound to    
grapple with the following  problem     
whenever it is clearly put before       
him3--,here are the ,faunae of the  same
 area during successive epochs4 ,show   

good cause for believing either  that   
these ,faunae have been derived from one
 another by gradual  modification1 or   
that the ,faunae have reached the area  
in question by  migration from some area
 in which they have undergone their     
development4    ,i propose to attempt to
 deal with this problem1 so far as it is
  exemplified by the distribution of the
 terrestrial ,vertebrata1 and ,i  shall 
endeavour to show you that it is capable
 of solution in a sense  entirely       
favourable to the doctrine of evolution4
    ,i have elsewhere#f stated at length
 the reasons which lead me to  recognise
 four primary distributional provinces  
for the terrestrial  ,vertebrata in the 
present world1 namely1--first1 the      
,novozelanian1 or  ,new-,zealand        
province2 secondly1 the ,australian     
province1 including  ,australia1        
,tasmania1 and the ,negrito ,islands2   
thirdly1 ,austro-,columbia1  or ,south  
,america plus ,north ,america as far as 
,mexico2 and fourthly1 the  rest of the 

world1 or ,arctogoea1 in which province 
,america north of  ,mexico constitutes  
one sub-province1 ,africa south of the  
,sahara a second1  ,hindostan a third1  
and the remainder of the ,old ,world a  
fourth4    ,footnote #f3 ,on the        
,classification and ,distribution of the
  ,alectoromorphoe2 ,proceedings of the 
,zoological ,society1 #ahfh4    ,now the
 truth which ,mr4 ,darwin perceived and 
promulgated as the law of  the          
succession of types is1 that1 in all    
these provinces1 the animals  found in  
,pliocene or later deposits are closely 
affined to those which  now inhabit the 
same provinces2 and that1 conversely1   
the forms  characteristic of other      
provinces are absent4 ,north and ,south 
,america1  perhaps1 present one or two  
exceptions to the last rule1 but they   
are  readily susceptible of explanation4
 ,thus1 in ,australia1 the later        
,tertiary mammals are marsupials        
7possibly with the exception of the ,dog
  and a ,rodent or two1 as at present74 

,in ,austro-,columbia1 the later        
,tertiary fauna exhibits numerous and   
varied forms of ,platyrrhine ,apes1     
,rodents1 ,cats1 ,dogs1 ,stags1         
,edentata1 and ,opossums2 but1 as at    
present1  no ,catarrhine ,apes1 no      
,lemurs1 no ,insectivora1 ,oxen1        
,antelopes1  ,rhinoceroses1 nor         
,didelphia other than ,opossums4 ,and in
 the widespread  ,arctogaeal province1  
the ,pliocene and later mammals belong  
to the same  groups as those which now  
exist in the province4 ,the law of      
succession of  types1 therefore1 holds  
good for the present epoch as compared  
with its  predecessor4 ,does it equally 
well apply to the ,pliocene fauna when  
we  compare it with that of the ,miocene
 epoch8 ,by great good fortune1 an      
extensive mammalian fauna of the latter 
epoch has now become known1 in  four    
very distant portions of the ,arctogaeal
 province which do not differ  greatly  
in latitude4 ,thus ,falconer and        
,cautley have made known the fauna  of  

the sub-,himalayas and the ,perim       
,islands2 ,gaudry that of ,attica2 many 
observers that of ,central ,europe and  
,france2 and ,leidy that of ,nebraska1  
on the eastern flank of the ,rocky      
,mountains4 ,the results are very       
striking4 ,the total ,miocene fauna     
comprises many genera and species of    
,catarrhine ,apes1 of ,bats1 of         
,insectivora2 of ,arctogaeal types of   
,rodentia2 of ,proboscidea2 of equine1  
rhinocerotic1 and tapirine  quadrupeds2 
of cameline1 bovine1 antilopine1        
cervine1 and traguline  ,ruminants2 of  
,pigs and ,hippopotamuses2 of           
,viverridoe and ,hyoenidoe  among other 
,carnivora2 with ,edentata allied to the
 ,aretogaeal  ,oryeteropus and ,manis1  
and not to the ,austro-,columbian       
,edentates4 ,the  only type present in  
the ,miocene1 but absent in the         
existing1 fauna of  ,eastern ,arctogaea1
 is that of the ,didelphidoe1 which1    
however1 remains  in ,north ,america4   
,but it is very remarkable that while   

the ,miocene fauna of the ,arctogaeal   
province1 as a whole1 is of the same    
character as the existing fauna of  the 
same province1 as a whole1 the component
 elements of the fauna were  differently
 associated4 ,in the ,miocene epoch1    
,north ,america possessed  ,elephants1  
,horses1 ,rhinoceroses1 and a great     
number and variety of  ,ruminants and   
,pigs1 which are absent in the present  
indigenous fauna2  ,europe had its      
,apes1 ,elephants1 ,rhinoceroses1       
,tapirs1 ,musk-deer1  ,giraffes1        
,hyaenas1 great ,cats1 ,edentates1 and  
,opossum-like ,marsupials1  which have  
equally vanished from its present fauna2
 and in ,northern  ,india1 the ,african 
types of ,hippopotamuses1 ,giraffes1 and
 ,elephants were  mixed up with what are
 now the ,asiatic types of the latter1  
and with  ,camels1 and ,semnopithecine  
and ,pithecine ,apes of no less         
distinctly  ,asiatic forms4    ,in fact 
the ,miocene mammalian fauna of ,europe 
and the ,himalayan regions  contains1   

associated together1 the types which are
 at present separately  located in the  
,south-,african and ,indian             
sub-provinces of ,arctogaea4 ,now  there
 is every reason to believe1 on other   
grounds1 that both ,hindostan1  south of
 the ,ganges1 and ,africa1 south of the 
,sahara1 were separated by a  wide sea  
from ,europe and ,north ,asia during the
 ,middle and ,upper ,eocene  epochs4    
,hence it becomes highly probable that  
the well-known  similarities1 and no    
less remarkable differences between the 
present  ,faunae of ,india and ,south   
,africa have arisen in some such fashion
 as the  following4 ,some time during   
the ,miocene epoch1 possibly when the   
,himalayan chain was elevated1 the      
bottom of the nummulitic sea was        
upheaved and converted into dry land1 in
 the direction of a line  extending from
 ,abyssinia to the mouth of the ,ganges4
 ,by this means1 the  ,dekhan on the one
 hand1 and ,south ,africa on the other1 
became connected  with the ,miocene dry 

land and with one another4 ,the ,miocene
 mammals  spread gradually over this    
intermediate dry land2 and if the       
condition of  its eastern and western   
ends offered as wide contrasts as the   
valleys of  the ,ganges and ,arabia do  
now1 many forms which made their way    
into ,africa  must have been different  
from those which reached the ,dekhan1   
while  others might pass into both these
 sub-provinces4    ,that there was a    
continuity of dry land between ,europe  
and ,north ,america  during the ,miocene
 epoch1 appears to me to be a necessary 
consequence of  the fact that many      
genera of terrestrial mammals1 such as  
,castor1  ,hystrix1 ,elephas1 ,mastodon1
 ,equus1 ,hipparion1 ,anchitherium1     
,rhinoceros1  ,cervus1 ,amphicyon1      
,hyoenarctos1 and ,machairodus1 are     
common to the  ,miocene formations of   
the two areas1 and have as yet been     
found 7except  perhaps ,anchitherium7 in
 no deposit of earlier age4 ,whether    
this  connection took place by the east1

 or by the west1 or by both sides of    
the ,old ,world1 there is at present no 
certain evidence1 and the question  is  
immaterial to the present argument2 but1
 as there are good grounds for  the     
belief that the ,australian province and
 the ,indian and ,south-,african        
sub-provinces were separated by sea from
 the rest of ,arctogaea before the      
,miocene epoch1 so it has been rendered 
no less probable1 by the  investigations
 of ,mr4 ,carrick ,moore and ,professor 
,duncan1 that ,austro-  ,columbia was   
separated by sea from ,north ,america   
during a large part of  the ,miocene    
epoch4    ,it is unfortunate that we    
have no knowledge of the ,miocene       
mammalian  fauna of the ,australian and 
,austro-,columbian provinces2 but1      
seeing that  not a trace of a           
,platyrrhine ,ape1 of a ,procyonine     
,carnivore1 of a  characteristically    
,south-,american ,rodent1 of a ,sloth1  
an ,armadillo1 or an  ,ant-eater has yet
 been found in ,miocene deposits of     

,arctogaea1 ,i cannot  doubt that they  
already existed in the ,miocene         
,austro-,columbian province4    ,nor is 
it less probable that the characteristic
 types of ,australian  ,mammalia were   
already developed in that region in     
,miocene times4    ,but                 
,austro-,columbia presents difficulties 
from which ,australia is free2          
,cantelidoe and ,tapirdoe are now       
indigenous in ,south ,america as they   
are in ,arctogaea2 and1 among the       
,pliocene ,austro-,columbian mammals1   
the  ,arctogaeal genera ,equus1         
,mastodon1 and ,machairodus are         
numbered4 ,are  these ,postmiocene      
immigrants1 or ,praemiocene natives8    
,still more perplexing are the strange  
and interesting forms ,toxodon1         
,macrauchenia1 ,typotherium1 and a new  
,anoplotherioid mammal                  
7,homalodotherhon7 which ,dr4           
,cunningham sent over to me some time   
ago  from ,patagonia4 ,i confess ,i am  
strongly inclined to surmise that these 

last1 at any rate1 are remnants of the  
population of ,austro-,columbia  before 
the ,miocene epoch1 and were not derived
 from ,arctogaea by way of  the north   
and east4    ,the fact that this immense
 fauna of ,miocene ,arctogaea is now    
fully and  richly represented only in   
,india and in ,south ,africa1 while it  
is shrunk  and depauperised in ,north   
,asia1 ,europe1 and ,north ,america1    
becomes at  once intelligible1 if we    
suppose that ,india and ,south ,africa  
had but a  scanty mammalian population  
before the ,miocene immigration1 while  
the  conditions were highly favourable  
to the new comers4 ,it is to be supposed
  that these new regions offered        
themselves to the ,miocene ,ungulates1  
as  ,south ,america and ,australia      
offered themselves to the cattle1 sheep1
 and  horses of modern colonists4 ,but1 
after these great areas were thus       
peopled1 came the ,glacial epoch1 during
 which the excessive cold1 to say       
nothing of depression and ice-covering1 

must have almost depopulated all  the   
northern parts of ,arctogaea1 destroying
 all the higher mammalian  forms1 except
 those which1 like the ,elephant and    
,rhinoceros1 could adjust  their coats  
to the altered conditions4 ,even these  
must have been driven  away from the    
greater part of the area2 only those    
,miocene mammals which  had passed into 
,hindostan and into ,south ,africa would
 escape decimation  by such changes in  
the physical geography of ,arctogaea4   
,and when the  northern hemisphere      
passed into its present condition1 these
 lost tribes  of the ,miocene ,fauna    
were hemmed by the ,himalayas1 the      
,sahara1 the ,red  ,sea1 and the        
,arabian deserts1 within their present  
boundaries4    ,now1 on the hypothesis  
of evolution1 there is no sort of       
difficulty in  admitting that the       
differences between the ,miocene forms  
of the mammalian  ,fauna and those which
 exist at present are the results of    
gradual  modification2 and1 since such  

differences in distribution as obtain   
are  readily explained by the changes   
which have taken place in the physical  
geography of the world since the        
,miocene epoch1 it is clear that the    
result of the comparison of the ,miocene
 and present ,faunae is distinctly  in  
favour of evolution4 ,indeed ,i may go  
further4 ,i may say that the  hypothesis
 of evolution explains the facts of     
,miocene1 ,pliocene1 and  ,recent       
distribution1 and that no other         
supposition even pretends to  account   
for them4 ,it is1 indeed1 a conceivable 
supposition that every  species of      
,rhinoceros and every species of        
,hyaena1 in the long succession  of     
forms between the ,miocene and the      
present species1 was separately         
constructed out of dust1 or out of      
nothing1 by supernatural power2 but     
until ,i receive distinct evidence of   
the fact1 ,i refuse to run the risk  of 
insulting any sane man by supposing that
 he seriously holds such a  notion4     

,let us now take a step further back in 
time1 and inquire into the  relations   
between the ,miocene ,fauna and its     
predecessor of the ,upper  ,eocene      
formation4    ,here it is to be         
regretted that our materials for forming
 a judgment are  nothing to be compared 
in point of extent or variety with those
 which are  yielded by the ,miocene     
strata4 ,however1 what we do know of    
this ,upper  ,eocene ,fauna of ,europe  
gives sufficient positive information to
 enable us  to draw some tolerably safe 
inferences4 ,it has yielded             
representatives of  ,insectivora1 of    
,cheiroptera1 of ,rodentia1 of          
,carnivora1 of  artiodactyle and        
perissodactyle ,ungulata1 and of        
opossum-like  ,marsupials4 ,no          
,australian type of ,marsupial has been 
discovered in the  ,upper ,eocene       
strata1 nor any ,edentate mammal4 ,the  
genera 7except perhaps  in the case of  
some of the ,insectivora1 ,cheiroptera1 
and ,rodentia7  are different from those

 of the ,miocene epoch1 but present a   
remarkable  general similarity to the   
,miocene and recent genera4 ,in several 
cases1 as  ,i have already shown1 it has
 now been clearly made out that the     
relation  between the ,eocene and       
,miocene forms is such that the ,eocene 
form is the  less specialised2 while its
 ,miocene ally is more so1 and the      
specialisation reaches its maximum in   
the recent forms of the same type4      
,so far as the ,upper ,eocene and the   
,miocene ,mammalian ,faunae are         
comparable1 their relations are such as 
in no way to oppose the  hypothesis that
 the older are the progenitors of the   
more recent forms1  while1 in some      
cases1 they distinctly favour that      
hypothesis4 ,the period  in tine and the
 changes in physical geography          
represented by the  nummulitic deposits 
are undoubtedly very great1 while the   
remains of  ,middle ,eocene and ,older  
,eocene ,mammals are comparatively few4 
,the general  facies of the ,middle     

,eocene ,fauna1 however1 is quite that  
of the ,upper4  ,the ,older ,eocene     
pre-nummulitic mammalian ,fauna contains
 ,bats1 two genera  of ,carivora1 three 
genera of ,ungulata 7probably all       
perissodactyle71  and a didelphid       
,marsupial2 all these forms1 except     
perhaps the ,bat and  the ,opossum1     
belong to genera which are not known to 
occur out of the  ,lower ,eocene        
formation4 ,the ,coryphodon appears to  
have been allied to  the ,miocene and   
later ,tapirs1 while ,pliolophus1 in its
 skull and  dentition1 curiously        
partakes of both artiodactyle and       
perissodactyle  characters2 the third   
trochanter upon its femur1 and its      
three-toed hind  foot1 however1 appear  
definitely to fix its position in the   
latter  division4    ,there is nothing1 
then1 in what is known of the older     
,eocene mammals of  the ,arctogaeal     
province to forbid the supposition that 
they stood in an  ancestral relation to 
those of the ,calcaire ,grossier and the

 ,gypsum of  the ,paris basin1 and that 
our present fauna1 therefore1 is        
directly  derived from that which       
already existed in ,arctogaea at the    
commencement  of the ,tertiary period4  
,but if we now cross the frontier       
between the  ,cainozoic and the         
,mesozoic faunae1 as they are preserved 
within the  ,arctogaeal area1 we meet   
with an astounding change1 and what     
appears to be  a complete and           
unmistakable break in the line of       
biological continuity4    ,among the    
twelve or fourteen species of ,mammalia 
which are said to have  been found in   
the ,purbecks1 not one is a member of   
the orders  ,cheiroptera1 ,rodentia1    
,ungulata1 or ,carnivora1 which are so  
well  represented in the ,tertiaries4   
,no ,insectivora are certainly known1   
nor  any opossum-like ,marsupials4 ,thus
 there is a vast negative difference    
between the ,cainozoic and the ,mesozoic
 mammalian faunae of ,europe4 ,but      
there is a still more important positive

 difference1 inasmuch as all  these     
,mammalia appear to be ,marsupials      
belonging to ,australian groups1  and   
thus appertaining to a different        
distributional province from the        
,eocene and ,miocene marsupials1 which  
are ,austro-,columbian4 ,so far as the  
imperfect materials which exist enable a
 judgment to be formed1 the same  law   
appears to have held good for all the   
earlier ,mesozoic ,mammalia4 ,of  the   
,stonesfield slate mammals1 one1        
,amphitherium1 has a definitely         
,australian character2 one1             
,phascolotherium1 may be either         
,dasyurid or  ,didelphine2 of a third1  
,stereognathus1 nothing can at present  
be said4  ,the two mammals of the       
,trias1 also1 appear to belong to       
,australian  groups4    ,every one is   
aware of the many curious points of     
resemblance between the  marine fauna of
 the ,european ,mesozoic rocks and that 
which now exists in  ,australia4 ,but if
 there was this ,australian facies about

 both the  terrestrial and the marine   
faunae of ,mesozoic ,europe1 and if     
there is this  unaccountable and immense
 break between the fauna of ,mesozoic   
and that of  ,tertiary ,europe1 is it   
not a very obvious suggestion that1 in  
the  ,mesozoic epoch1 the ,australian   
province included ,europe1 and that the 
,arctogaeal province was contained      
within other limits8 ,the ,arctogaeal   
province is at present enormous1 while  
the ,australian is relatively  small4   
,why should not these proportions have  
been different during the  ,mesozoic    
epoch8    ,thus ,i am led to think that 
by far the simplest and most rational   
mode of  accounting for the great change
 which took place in the living         
inhabitants of the ,european area at the
 end of the ,mesozoic epoch1 is the     
supposition that it arose from a vast   
alteration of the physical  geography of
 the globe2 whereby an area long        
tenanted by ,cainozoic forms  was       
brought into such relations with the    

,european area that migration  from the 
one to the other became possible1 and   
took place on a great  scale4    ,this  
supposition relieves us1 at once1 from  
the difficulty in which we  were left1  
some time ago1 by the arguments which ,i
 used to demonstrate  the necessity of  
the existence of all the great types of 
the ,eocene epoch  in some antecedent   
period4    ,it is this ,mesozoic        
continent 7which may well have lain in  
the  neighbourhood of what are now the  
shores of the ,north ,pacific ,ocean7   
which ,i suppose to have been occupied  
by the ,mesozoic ,monodelphia2 and  it  
is in this region that ,i conceive they 
must have gone through the long  series 
of changes by which they were           
specialised into the forms which we     
refer to different orders4 ,i think it  
very probable that what is now  ,south  
,america may have received the          
characteristic elements of its          
mammalian fauna during the ,mesozoic    
epoch2 and there can be little doubt    

that the general nature of the change   
which took place at the end of the      
,mesozoic epoch in ,europe was the      
upheaval of the eastern and northern    
regions of the ,mesozoic sea-bottom into
 a westward extension of the  ,mesozoic 
continent1 over which the mammalian     
fauna1 by which it was  already peopled1
 gradually spread4 ,this invasion of the
 land was prefaced  by a previous       
invasion of the ,cretaceous sea by      
modern forms of mollusca  and fish4     
,it is easy to imagine how an analogous 
change might come about in the  existing
 world4 ,there is1 at present1 a great  
difference between the  fauna of the    
,polynesian ,islands and that of the    
west coast of ,america4  ,the animals   
which are leaving their spoils in the   
deposits now forming in  these          
localities are widely different4 ,hence1
 if a gradual shifting of  the deep sea1
 which at present bars migration between
 the easternmost of  these islands and  
,america1 took place to the westward1   

while the ,american  side of the        
sea-bottom was gradually upheaved1 the  
palaeontologist of the  future would    
find1 over the ,pacific area1 exactly   
such a change as ,i am  supposing to    
have occurred in the ,north-,atlantic   
area at the close of the  ,mesozoic     
period4 ,an ,australian fauna would be  
found underlying an  ,american fauna1   
and the transition from the one to the  
other would be as  abrupt as that       
between the ,chalk and lower            
,tertiaries2 and as the  drainage-area  
of the newly formed extension of the    
,american continent  gave rise to rivers
 and lakes1 the mammals mired in their  
mud would  differ from those of like    
deposits on the ,australian side1 just  
as the  ,eocene mammals differ from     
those of the ,purbecks4    ,how do      
similar reasonings apply to the other   
great change of life--that  which took  
place at the end of the ,palaeozoic     
period8    ,in the ,triassic epoch1 the 
distribution of the dry land and of     

terrestrial vertebrate life appears to  
have been1 generally1 similar to  that  
which existed in the ,mesozoic epoch2 so
 that the ,triassic continents  and     
their faunae seem to be related to the  
,mesozoic lands and their faunae1  just 
as those of the ,miocene epoch are      
related to those of the present  day4   
,in fact1 as ,i have recently           
endeavoured to prove to the ,society1   
there was an ,arctogaeal continent and  
an ,arctogaeal province of  distribution
 in ,triassic times as there is now2 and
 the ,sauropsida and  ,marsupialia which
 constituted that fauna were1 ,i doubt  
not1 the  progenitors of the ,sauropsida
 and ,marsupialia of the whole ,mesozoic
  epoch4    ,looking at the present     
terrestrial fauna of ,australia1 it     
appears to me  to be very probable that 
it is essentially a remnant of the fauna
 of the  ,triassic1 or even of an       
earlier1 age#g in which case ,australia 
must at  that time have been in         
continuity with the ,arctogaeal         

continent4    ,footnote #g3 ,since this 
,address was read1 ,mr4 ,krefft has sent
 us news of  the discovery in ,australia
 of a freshwater fish of strangely      
,palaeozoic  aspect1 and apparently a   
,ganoid intermediate between ,dipterus  
and  ,lepidosiren4 ,the now well-known  
,ceratodus4 #ahid4    ,but now comes the
 further inquiry1 ,where was the highly 
differentiated  ,sauropsidan fauna of   
the ,trias in ,palaeozoic times8 ,the   
supposition that  the ,dinosaurian1     
,crocodilian1 ,dicynodontian1 and to    
,plesiosaurian types  were suddenly     
created at the end of the ,permian epoch
 may be dismissed1  without further     
consideration1 as a monstrous and       
unwarranted assumption4  ,the           
supposition that all these types were   
rapidly differentiated out of           
,lacertilia in the time represented by  
the passage from the ,palaeozoic to  the
 ,mesozoic formation1 appears to me to  
be hardly more credible1 to say  nothing
 of the indications of the existence of 

,dinosaurian forms in the  ,permian     
rocks which have already been obtained4 
,for my part1 ,i entertain no sort of   
doubt that the ,reptiles1 ,birds1 and   
,mammals of the ,trias are the direct   
descendants of ,reptiles1 ,birds1 and   
,mammals which existed in the latter    
part of the ,palaeozoic epoch1 but not  
in any area of the present dry land     
which has yet been explored by the      
geologist4    ,this may seem a bold     
assumption1 but it will not appear      
unwarrantable to  those who reflect upon
 the very small extent of the earth's   
surface which  has hitherto exhibited   
the remains of the great ,mammalian     
fauna of the  ,eocene times4 ,in this   
respect1 the ,permian land ,vertebrate  
fauna appears  to me to be related to   
the ,triassic much as the ,eocene is to 
the ,miocene4  ,terrestrial reptiles    
have been found in ,permian rocks only  
in three  localities2 in some spots of  
,france1 and recently of ,england1 and  
over a  more extensive area in ,germany4

 ,who can suppose that the few fossils  
yet  found in these regions give any    
sufficient representation of the        
,permian  fauna8    ,it may be said that
 the ,carboniferous formations          
demonstrate the  existence of a vast    
extent of dry land in the present       
dry-land area1 and  that the supposed   
terrestrial ,palaeozoic ,vertebrate     
,fauna ought to have  left its remains  
in the ,coal-measures1 especially as    
there is now reason  to believe that    
much of the coal was formed by the      
accumulation of spores  and sporangia on
 dry land4 ,but if we consider the      
matter more closely1 ,i  think that this
 apparent objection loses its force4 ,it
 is clear that1  during the             
,carboniferous epoch1 the vast area of  
land which is now  covered by           
,coal-measures must have been undergoing
 a gradual depression4  ,the dry land   
thus depressed must1 therefore1 have    
existed1 as such1  before the           
,carboniferous epoch--in other words1 in

 ,devonian times--and  its terrestrial  
population may never have been other    
than such as existed  during the        
,devonian1 or some previous epoch1      
although much higher forms  may have    
been developed elsewhere4    ,again1 let
 me say that ,i am making no gratuitous 
assumption of  inconceivable changes4   
,it is clear that the enormous area of  
,polynesia  is1 on the whole1 an area   
over which depression has taken place to
 an  immense extent2 consequently a     
great continent1 or assemblage of       
subcontinental masses of land must have 
existed at some former time1 and  that  
at a recent period1 geologically        
speaking1 in the area of the  ,pacific4 
,but if that continent had contained    
,mammals1 some of them must  have       
remained to tell the tale2 and as it is 
well known that these  islands have no  
indigenous ,mammalia1 it is safe to     
assume that none  existed4 ,thus1 midway
 between ,australia and ,south ,america1
 each of which  possesses an abundant   

and diversified mammalian fauna1 a mass 
of land1  which may have been as large  
as both put together1 must have existed 
without a mammalian inhabitant4 ,suppose
 that the shores of this great  land    
were fringed1 as those of tropical      
,australia are now1 with belts of       
mangroves1 which would extend landwards 
on the one side1 and be buried  beneath 
littoral deposits on the other side1 as 
depression went on2 and  great beds of  
mangrove lignite might accumulate over  
the sinking land4  ,let upheaval of the 
whole now take place1 in such a manner  
as to bring  the emerging land into     
continuity with the ,south-,american or 
,australian  continent1 and1 in course  
of time1 it would be peopled by an      
extension of  the fauna of one of these 
two regions--just as ,i imagine the     
,european  ,permian dry land to have    
been peopled4    ,i see nothing whatever
 against the supposition that           
distributional  provinces of terrestrial
 life existed in the ,devonian epoch1   

inasmuch as  ,m4 ,barrande has proved   
that they existed much earlier4 ,i am   
aware of no  reason for doubting that1  
as regards the grades of terrestrial    
life  contained in them1 one of these   
may have been related to another as ,new
  ,zealand is to ,australia1 or as      
,australia is to ,india1 at the present 
day4  ,analogy seems to me to be rather 
in favour of1 than against1 the         
supposition that while only ,ganoid     
fishes inhabited the fresh waters of    
our ,devonian land1 ,amphibia and       
,reptilia1 or even higher forms1 may    
have existed1 though we have not yet    
found them4 ,the earliest               
,carboniferous ,amphibia now known1 such
 as ,anthracosaurus1 are so  highly     
specialised that ,i can by no means     
conceive that they have been  developed 
out of piscine forms in the interval    
between the ,devonian and  the          
,carboniferous periods1 considerable as 
that is4 ,and ,i take refuge in  one of 
two alternatives3 either they existed in

 our own area during the  ,devonian     
epoch and we have simply not yet found  
them2 or they formed part  of the       
population of some other distributional 
province of that day1 and  only entered 
our area by migration at the end of the 
,devonian epoch4  ,whether ,reptilia and
 ,mammalia existed along with them is to
 me1 at  present1 a perfectly open      
question1 which is just as likely to    
receive an  affirmative as a negative   
answer from future inquirers4    ,let me
 now gather together the threads of my  
argumentation into the form  of a       
connected hypothetical view of the      
manner in which the distribution  of    
living and extinct animals has been     
brought about4    ,i conceive that      
distinct provinces of the distribution  
of terrestrial  life have existed since 
the earliest period at which that life  
is  recorded1 and possibly much earlier2
 and ,i suppose1 with ,mr4 ,darwin1 that
  the progress of modification of       
terrestrial forms is more rapid in areas

  of elevation than in areas of         
depression4 ,i take it to be certain    
that  ,labyrinthodont ,amphibia existed 
in the distributional province which    
included the dry land depressed during  
the ,carboniferous epoch2 and ,i        
conceive that1 in some other            
distributional provinces of that day1   
which  remained in the condition of     
stationary or of increasing dry land1   
the  various types of the terrestrial   
,sauropsida and of the ,mammalia were   
gradually developing4    ,the ,permian  
epoch marks the commencement of a new   
movement of upheaval in  our area1 which
 dry land existed in ,north ,america1   
,europe1 ,asia1 and  ,africa1 as it does
 now4 ,into this great new continental  
area the ,mammals1  ,birds1 and         
,reptiles developed during the          
,palaeozoic epoch spread1 and  formed   
the great ,triassic ,arctogaeal         
province4 ,but1 at the end of the       
,triassic period1 the movement of       
depression recommenced in our area1     

though it was doubtless balanced by     
elevation elsewhere2 modification and   
development1 checked in the one         
province1 went on in that elsewhere2    
and the chief forms of ,mammals1 ,birds 
and ,reptiles1 as we know them1 were    
evolved and peopled the ,mesozoic       
continent4 ,i conceive ,australia to    
have  become separated from the         
continent as early as the end of the    
,triassic  epoch1 or not much later4    
,the ,mesozoic continent must1 ,i       
conceive1 have  lain to the east1 about 
the shores of the ,north ,pacific and   
,indian  ,oceans2 and ,i am inclined to 
believe that it continued along the     
eastern  side of the ,pacific area to   
what is now the province of             
,austro-,columbia1  the characteristic  
fauna of which is probably a remnant of 
the population  of the latter part of   
this period4    ,towards the latter part
 of the ,mesozoic period the movement of
 upheaval  around the shores of the     
,atlantic once more recommenced1 and was

 very  probably accompanied by a        
depression around those of the ,pacific4
 ,the  ,vertebrate fauna elaborated in  
the ,mesozoic continent moved westward  
and  took possession of the new lands1  
which gradually increased in extent up  
to1 and in some directions after1 the   
,miocene epoch4    ,it is in favour of  
this hypothesis1 ,i think1 that it is   
consistent with  the persistence of a   
general uniformity in the positions of  
the great  masses of land and water4    
,from the ,devonian period1 or earlier1 
to the  present day1 the four great     
oceans1 ,atlantic1 ,pacific1 ,arctic1   
and  ,antarctic1 may have occupied their
 present positions1 and only their      
coasts and channels of communication    
have undergone an incessant  alteration4
 ,and1 finally1 the hypothesis ,i have  
put before you requires  no supposition 
that the rate of change in organic life 
has been either  greater or less in     
ancient times than it is now2 nor any   
assumption1  either physical or         

biological1 which has not its           
justification in  analogous phenomena of
 existing nature4    ,i have now only to
 discharge the last duty of my office1  
which is to  thank you1 not only for the
 patient attention with which you have  
listened to me so long to-day1 but also 
for the uniform kindness with  which1   
for the past two years1 you have        
rendered my endeavours to perform  the  
important1 and often laborious1         
functions of your ,president a  pleasure
 instead of a burden4