,,! ,,/ory ,,( ,,! ,,liv+ ,,ma*9e ,a ,,review ,,( ,,! ,,conclusions ,,( ,,mod]n ,,biology ,,9 ,,reg>d ,,to ,,! ,,me*anism ,,:i* ,,controls ,,! ,,ph5om5a ,,( ,,liv+ ,,activity ,,by ,h4,w4 ,,conn ,,pr(essor ,,( ,,biology ,,9 ,,wesleyan ,,univ]sity ,,au?or ,,( ,,! ,,/ory ,,( ,,g]m ,,life1 ,,evolution ,,( ,,to-,,day1 ,,! ,,liv+ ,,_w1 ,,etc4 ,,) ,,fifty ,,illu/rations ,,new ,,york ,d4 ,,appleton ,,& ,,company #aijc ,,copyright1 #ahii1 ,by ,d4 ,,appleton ,,& ,,company4 ,,preface4 ,t ! liv+ body is a ma*9e is a /atem5t t is frequ5tly made )\t any v accurate idea z to :at x means4 ,on ! "o h& x is made ) a belief t a /rict comp>ison c be made betwe5 ! body & an ord9>y1 artificial ma*9e1 & t liv+ be+s are ?us r$uc$ to simple me*anisms2 on ! o!r h& x is made loosely1 )\t any special ?\ght z to its significance1 & c]ta9ly ) no conception t x r$uces life to a me*anism4 ,! conclusion t ! liv+ body is a ma*9e1 involv+ z x does a me*anical conception ( life1 is "o ( mo/ extreme philosophical importance1 & no "o int]e/$ 9 ! philosophical conception ( nature c fail to h an int]e/ 9 ?is problem ( ! /rict accuracy ( ! /atem5t t ! body is a ma*9e4 ,d\btless ! complete /ory ( ! liv+ ma*9e c n yet be told2 b ! /udies ( ! la/ fifty ye>s h br\ght u s f> along ! road t[>d its completion t a review ( ! progress made & a glance at ! yet unexplor$ realms & unansw]$ que/ions w be pr(itable4 ,= ?is purpose ?is "w is design$1 ) ! hope t x may give a cle> idea ( ! tr5d ( rec5t biological sci5ce & ( ! advances made t[>d ! solution ( ! problem ( life4 ,,middlet[n1 ,,conn41 ,u4,s4,a4 ,octob] #a1 #ahih4 ,,cont5ts4 ,,page ,,introduction--,biology a new sci5ce--,hi/orical biology--,cons]vation ( en]gy--,evolution--,cytology--,new aspects ( biology--,! me*anical nature ( liv+ organisms--,significance ( ! new biological problems--,outl9e ( ! subject #a ,,"p ,i4 ,,! ,,runn+ ,,( ,,! ,,liv+ ,,ma*9e4 ,,*apt] ,i4 ,,is ,,! ,,body ,a ,,ma*9e8 ,:at is a ma*9e8--,a g5]al comp>ison ( a body & a ma*9e--,details ( ! action ( ! ma*9e--,physical explanation ( ! *ief vital functions--,! liv+ body is a ma*9e--,! liv+ ma*9e con/ructive z well z de/ructive--,! vital factor #ai ,,*apt] ,,ii4 ,,! ,,cell ,,& ,,protoplasm4 ,vital prop]ties--,! discov]y ( cells--,! cell doctr9e--,! cell--,! cellul> /ructure ( organisms--,! cell wall--,protoplasm--,! reign ( protoplasm--,! decl9e ( ! reign ( protoplasm--,! /ructure ( protoplasm--,! nucleus--,c5trosome--,function ( ! nucleus--,cell division or k>yok9esis--,f]tilization ( ! egg--,! significance ( f]tilization--,:at is protoplasm8--,reaction aga9/ ! cell doctr9e--,fundam5tal vital activities z locat$ 9 cells--,summ>y #ed ,,"p ,,ii4 ,,! ,,build+ ,,( ,,! ,,liv+ ,,ma*9e4 ,,*apt] ,,iii4 ,,! ,,factors ,,conc]n$ ,,9 ,,! ,,build+ ,,( ,,! ,,liv+ ,,ma*9e4 ,hi/ory ( ! liv+ ma*9e--,evid5ce = ?is hi/ory--,hi/orical--,embryological--,ana tomical--,significance ( ^! s\rces ( hi/ory--,=ces at "w 9 ! build+ ( ! liv+ ma*9e--,reproduction--,h]$ity--,v>iation --,inh]itance ( v>iations--,me?od ( ma*9e build+--,migration & isolation--,direct influ5ce ( environm5t--,consci\sness--,summ>y ( ,nature's p[] ( build+ ma*9es--,! orig9 ( ! cell ma*9e--,g5]al summ>y #aca ,,li/ ,,( ,,illu/rations4 ,,figure ,,page ,amoeba ,polypodia 9 six successive /ages ( division ,frontispiece #a4 ,figure illu/rat+ osmosis #cj #b4 ,figure illu/rat+ osmosis #ca #c4 ,diagram ( ! inte/9al walls #cb #d4 ,diagram ( a s+le villus #cc #e4 ,enl>g$ figure ( f\r cells 9 ! villus membrane #cc #f4 ,a bit ( muscle %[+ blood-vessels #cf #g4 ,a bit ( b>k %[+ cellul> /ructure #fa #h4 ,successive /ages 9 ! division ( ! develop+ egg #fc #i4 ,a typical cell #fe #aj4 ,cells at a root tip #ff #aa4 ,section ( a leaf %[+ cells ( diff]5t %apes #ff #ab4 ,plant cells ) ?ick walls1 f a f]n #fg #ac4 ,section ( potato #fg #ad4 ,v>i\s %ap$ wood cells f plant tissue #fh #ae4 ,a bit ( c>tilage #fh #af4 ,frogs' blood #fi #ag4 ,a bit ( bone #fi #ah4 ,connective tissue #gj #ai4 ,a piece ( n]ve fibre #gj #bj4 ,a muscle fibre #ga #ba4 ,a complex cell1 vorticella #ga #bb4 ,an amoeba #gc #bc4 ,a cell z x appe>s to ! mod]n microscope #hf #bd4 ,a cell cut into pieces1 ea* conta9+ a bit ( nucleus #hi #be4 ,a cell cut 9 pieces1 only "o ( :i* conta9s any nucleus #ij #bf4 ,diff]5t =ms ( nucleii #ic #bg & #bh4 ,two /ages 9 cell division #if #bi & #cj4 ,/ages 9 cell division #ih #ca & #cb4 ,late/ /ages 9 cell division #ajj #cc4 ,an egg #ajc #cd & #ce4 ,/ages 9 ! process ( f]tilization ( ! egg #ajd #cf & #cg4 ,/ages 9 ! process ( f]tilization ( ! egg #aje #ch1 #ci1 & #dj4 ,/ages 9 f]tilization ( ! egg #ajf #da & #db4 ,late/ /ages 9 ! f]tilization ( ! egg #aji #dc & #dd4 ,two /ages 9 ! division ( ! egg #aaa #de4 ,a gr\p ( cells result+ f division1 ! fir/ /ep 9 ma*9e build+ #ace #df4 ,a lat] /ep 9 ma*9e build+1 ! ga/rula #ace #dg4 ,! arm ( a monkey #add #dh4 ,! arm ( a bird #add #di4 ,! arm ( an anci5t half-bird1 half-reptile animal #add #ej4 ,diagram to illu/rate ! pr9ciple ( h]$ity #aef ,,! ,,/ory ,,( ,,! ,,liv+ ,,ma*9e4 ,,introduction4 ,biology a ,new ,sci5ce4--,9 rec5t ye>s biology has be5 spok5 ( z a new sci5ce4 ,?irty ye>s ago dep>tm5ts ( biology 7 practically unkn[n 9 educational in/itutions4 ,to-day none ( our high] in/itutions ( le>n+ consid]s itself equipp$ )\t su* a dep>tm5t4 ,?is seems to be some:at /range4 ,biology is simply ! /udy ( liv+ ?+s2 & liv+ nature has be5 /udi$ z long z mank9d has /udi$ any?+4 ,ev5 ,ari/otle1 f\r hundr$ ye>s be=e ,*ri/1 classifi$ liv+ ?+s4 ,f ?is f\ndation d[n ?r\gh ! c5turies liv+ ph5om5a h receiv$ con/ant att5tion4 ,rec5t c5turies h paid m att5tion to liv+ ?+s ?an to any o!r objects 9 nature4 ,l9nu erect$ 8 sy/ems ( classification be=e mod]n *emi/ry came into exi/5ce2 ! sy/ematic /udy ( zoology ant$at$ t ( physics2 & long be=e geology _h be5 conceiv$ 9 its mod]n =m1 ! animal & vegetable k+doms _h be5 compreh5d$ 9 a sci5tific sy/em4 ,h[1 !n1 c biology be call$ a new sci5ce ,:5 x is old] ?an all ! o!rs8 ,!re mu/ be "s reason :y ?is1 ! olde/ ( all1 has be5 rec5tly call$ a new sci5ce1 & "s explanation ( ! fact t x has only rec5tly advanc$ to =m a di/9ct dep>tm5t 9 our educational sy/em4 ,! reason is n difficult to f9d4 ,biology is a new sci5ce1 n because ! objects x /udies are new1 b because x has adopt$ a new relation to ^? objects & is /udy+ !m f a new /&po9t4 ,animals & plants h be5 /udi$ long en\gh1 b n z we n[ /udy !m4 ,p]haps ! new attitude adopt$ t[>d liv+ nature may be t]sely express$ by say+ t 9 ! pa/ x has be5 /udi$ z at re/1 :ile to-day x is /udi$ z 9 motion4 ,! old] zoologi/s & botani/s conf9$ !mselves l>gely to ! /udy ( animals & plants simply z s _m museum specim5s to be arrang$ on %elves ) appropriate names4 ,! mod]n biologi/ is /udy+ ^! same objects z int5sely active be+s & z p>ts ( an ev]-*ang+ hi/ory4 ,to ! /ud5t ( natural hi/ory fifty ye>s ago1 animals & plants 7 objects to be classifi$2 to ! biologi/ ( to-day1 !y are objects to be expla9$4 ,to und]/& ?is new attitude1 a brief review ( ! hi/ory ( ! fundam5tal features ( philosophical ?\ght w be necess>y4 ,:51 long ago1 man began to ?9k ^u ! ph5om5a ( nature1 he 0 able to und]/& almo/ no?+4 ,9 8 inability to compreh5d ! activities go+ on ar\nd him he came to reg>d ! =ces ( nature z manife/ations ( "s sup]natural be+s4 ,?is 0 em95tly natural4 ,he _h a direct consci\sness ( 8 own p[] to act1 & x 0 natural = him to assume t ! activities go+ on ar\nd him 7 caus$ by simil> p[]s on ! "p ( "s be+ l himself1 only sup]ior to him4 ,?us he came to fill ! unse5 univ]se ) gods controll+ ! =ces ( nature4 ,! w9d 0 ! brea? ( "o god1 & ! lightn+ a bolt ?r[n f ! h&s ( ano!r4 ,) advanc+ ?\ght ! ideas ( poly!ism lat] gave place to ! nobl] conception ( mono!ism4 ,b = a long "t yet ! same ideas ( ! sup]natural1 z relat$ to ! natural1 reta9$ _! place 9 man's philosophy4 ,^? ph5om5a :i* he ?\ght he c\ld und]/& 7 look$ ^u z natural1 :ile ^? :i* he c\ld n und]/& 7 look$ ^u z sup]natural1 & z produc$ by ! direct p]sonal activity ( "s div9e ag5cy4 ,z ! c5turies pass$1 & man's p[] ( obs]vation became ke5] & 8 ?9k+ m logical1 _m ( ! hi!rto my/]i\s ph5om5a became intelligible & subject to simple explanations4 ,z fa/ z ?is occurr$ ^! ph5om5a 7 unconsci\sly tak5 f ! realm ( ! sup]natural & plac$ among natural ph5om5a :i* c\ld be expla9$ by natural laws4 ,among ! fir/ my/]ies to be ?us compreh5d$ by natural law 7 ^? ( a/ronomy4 ,! complicat$ & yet h>moni\s motions ( ! heav5ly bodies _h hi!rto be5 inexplicable4 ,to expla9 !m _m a sublime conception ( almighty p[] _h aris51 & ! /udy ( ! heav5ly bodies ev] gave rise to ! highe/ ?\ghts ( ,deity4 ,b ,newton's law ( gravitation r$uc$ ! :ole to ! greate/ simplicity4 ,?r\gh ! law & =ce ( gravitation ^! my/]ies 7 br\ght )9 ! grasp ( human und]/&+4 ,!y ceas$ to be look$ ^u z sup]natural1 & became natural ph5om5a z soon z ! =ce ( gravitation 0 accept$ z a "p ( nature4 ,9 o!r bran*es ( natural ph5om5a ! same hi/ory foll[$4 ,! =ces & laws ( *emical aff9ity 7 =mulat$ & /udi$1 & physical laws & =ces 7 compreh5d$4 ,z ^! natural =ces 7 grasp$ x became1 little by little1 evid5t t ! v>i\s ph5om5a ( nature 7 simply ! result ( nature's =ces act+ 9 accordance ) nature's laws4 ,ph5om5a hi!rto my/]i\s 7 "o aft] ano!r br\ght )9 ! realm ( law1 & z ?is occurr$ a small] & small] portion ( !m 7 left )9 ! realm ( ! s-call$ sup]natural4 ,by ! middle ( ?is c5tury ?is advance _h rea*$ a po9t :]e sci5ti/s1 at lea/1 7 ready to believe t nature's =ces 7 all-p[]ful to acc\nt = nature's ph5om5a4 ,sci5ce _h pass$ f ! reign ( my/icism to ! reign ( law4 ,b aft] *emi/ry & physics1 ) all ! =ces t !y c\ld mu/]1 _h exhau/$ _! p[]s 9 expla9+ natural ph5om5a1 !re app>5tly rema9$ "o class ( facts :i* 0 /ill left 9 ! realm ( ! sup]natural & ! unexpla9$4 ,! ph5om5a associat$ ) liv+ ?+s rema9$ ne>ly z my/]i\s z ev]4 ,life appe>$ to be ! mo/ inexplicable ph5om5a ( nature1 & none ( ! =ces & laws :i* _h be5 f\nd suffici5t to acc\nt = o!r dep>tm5ts ( nature appe>$ to h mu* influ5ce 9 r5d]+ intelligible ! ph5om5a ( life4 ,liv+ organisms appe>$ to be actuat$ by an entirely unique =ce4 ,_! %apes & /ructure %[$ s _m m>vell\s adaptations to _! surr\nd+s z to r5d] x app>5tly c]ta9 t _! adju/m5t mu/ h be5 ! result ( "s intellig5t plann+1 & n ! outcome ( bl9d =ce4 ,:o c\ld look ^u ! adaptation ( ! eye to light )\t see+ 9 ,x ! result ( intellig5t design8 ,adaptation to conditions is se5 9 all animals & plants4 ,^! organisms are evid5tly complicat$ ma*9es ) _! p>ts intricately adapt$ to ea* o!r & to surr\nd+ conditions4 ,ap>t f animals & plants ! only o!r simil>ly adju/$ ma*9es are ^? :i* h be5 made by human intellig5ce2 & ! inf]5ce seem$ to be cle> t a simil> intellig5ce 0 ne$$ to acc\nt = ! liv+ ma*9e4 ,! bl9d action ( physical =ces seem$ inadequate4 ,?us ! ph5om5a ( life1 :i* _h be5 /udi$ long] ?an any o!r phase ( nature1 cont9u$ to /& alo( f ! re/ & refus$ to fall into l9e ) ! g5]al drift ( ?\ght4 ,! liv+ _w seem$ to give no promise ( be+ includ$ among natural ph5om5a1 b /ill p]si/$ 9 reta9+ its sup]natural aspect4 ,x is ! attempt to expla9 ! ph5om5a ( ! liv+ _w by ! same k9d ( natural =ces t h be5 adequate to acc\nt = o!r ph5om5a1 t has creat$ mod]n ,biology4 ,s long z /ud5ts simply /udi$ animals & plants z objects = classification1 z museum objects1 or z objects :i* _h be5 /ation>y 9 ! hi/ory ( nature1 s long 7 !y simply foll[+ along ! same l9es 9 :i* _! pr$ecessors _h be5 travell+4 ,b :5 once !y began to ask if liv+ nature 7 n p]haps subject to an intellig5t explanation1 to /udy liv+ ?+s z "p ( a g5]al hi/ory & to look ^u !m z active mov+ objects ^: motion & ^: hi/ory might p]haps be acc\nt$ =1 !n at once 0 creat$ a new dep>tm5t ( ?\ght & a new sci5ce inaugurat$4 ,hi/orical ,geology4--,prep>ation _h be5 made = ?is new me?od ( /udy+ life by ! =mulation ( a numb] ( important sci5tific discov]ies4 ,prom95t among ^! /ood hi/orical geology4 ,t ! e>? _h left a record ( h] hi/ory 9 ! rocks 9 language pla9 en\gh to be read appe>s to h be5 impress$ ^u sci5ti/s 9 ! la/ ( ! c5tury4 ,t ! e>? has _h a hi/ory & t man c\ld read x became m & m ?or\ghly und]/ood z ! fir/ decades ( ?is c5tury pass$4 ,! read+ ( t hi/ory prov$ a some:at difficult task4 ,x 0 writt5 9 a /range language1 & x requir$ _m ye>s to discov] ! key to ! record4 ,b "u ! influ5ce ( ! writ+s ( ,lyell1 j be=e ! middle ( ! c5tury1 x began to appe> t ! key to ?is language is to be f\nd by simply op5+ ! eyes & obs]v+ :at is go+ on ar\nd u to-day4 ,a m extraord9>y & m important discov]y has h>dly ev] be5 made1 = x conta9$ ! f\ndation ( ne>ly all sci5tific discov]ies :i* h be5 made s9ce4 ,?is discov]y proclaim$ t an application ( ! =ces /ill at "w to-day on ! e>?'s surface1 b cont9u$ ?r\gh\t long ages1 w furni% ! int]pretation ( ! hi/ory writt5 9 ! rocks1 & ?us an explanation ( ! hi/ory ( ! e>? itself4 ,! sl[ elevation ( ! e>?'s cru/1 su* z is /ill go+ on to-day1 w\ld1 if cont9u$1 produce m\nta9s2 & ! wa%+ away ( ! l& by ra9s & floods1 su* z we see all ar\nd u1 w\ld1 if cont9u$ ?r\gh ! long c5turies1 produce ! valleys & gorges :i* s a/\nd u4 ,! explanation ( ! pa/ is to be f\nd 9 ! pres5t4 ,b ?is geological hi/ory told ( a hi/ory ( life z well z a hi/ory ( rocks4 ,! hi/ory ( ! rocks has inde$ be5 b\nd up 9 ! hi/ory ( life1 & no soon] did x appe> t ! e>?'s cru/ has _h a readable hi/ory ?an x appe>$ t liv+ nature _h a p>allel hi/ory4 ,if ! pres5t is a key to ! pa/ 9 int]pret+ geological hi/ory1 %\ld n ! same be true ( ?is hi/ory ( life8 ,x 0 inevitable t problems ( life %\ld come to ! front1 & t ! /udy ( life f ! dynamical /&po9t1 r ?an a /atical1 %\ld ensue4 ,mod]n biology 0 ! *ild ( hi/orical geology4 ,b hi/orical geology alone c\ld nev] h l$ to ! dynamical phase ( mod]n biology4 ,?ree o!r conceptions h contribut$ 9 an ev5 great] degree to ! developm5t ( ?is sci5ce4 ,cons]vation ( ,en]gy4--,! fir/ ( ^! 0 ! doctr9e ( cons]vation ( en]gy & ! correlation ( =ces4 ,?is doctr9e is really q simple1 & may be outl9$ z foll[s3 ,9 ! univ]se1 z we "k x1 !re exi/s a c]ta9 am\nt ( en]gy or p[] ( do+ "w4 ,?is am\nt ( en]gy c nei!r be increas$ nor decreas$2 en]gy c no m be creat$ or de/roy$ ?an matt]4 ,x exi/s1 h[ev]1 9 a v>iety ( =ms1 :i* may be ei!r active or passive4 ,9 ! active /ate x takes "s =m ( motion4 ,! v>i\s =ces :i* we recognize 9 nature--heat1 light1 electricity1 *emism1 etc4--are simply =ms ( motion1 & ?us =ms ( ?is en]gy4 ,^! v>i\s types ( en]gy1 be+ only expressions ( ! univ]sal en]gy1 are conv]tible into ea* o!r 9 su* a way t :5 "o disappe>s ano!r appe>s4 ,a cannon ball fly+ ?r\gh ! air exhibits en]gy ( motion2 b x /rikes an ob/acle & /ops4 ,! motion has app>5tly /opp$1 b an exam9ation %[s t ?is is n ! case4 ,! cannon ball & ! object x /rikes h be5 heat$1 & ?us ! motion ( ! ball has simply be5 trans=m$ into a diff]5t =m ( motion1 :i* we call heat4 ,or1 aga91 ! heat set free "u ! locomotive boil] is conv]t$ by ma*9]y into ! motion ( ! locomotive4 ,by /ill diff]5t me*anism x may be conv]t$ into electric =ce4 ,all =ms ( motion are readily conv]tible into ea* o!r1 & ea* =m 9 :i* en]gy appe>s is only a phase ( ! total en]gy ( nature4 ,a second condition ( en]gy is en]gy at re/1 or pot5tial en]gy4 ,a /one on ! ro( ( a h\se is at re/1 b by virtue ( its position x has a c]ta9 am\nt ( pot5tial en]gy1 s9ce1 if dislodg$1 x w fall to ! gr\nd1 & ?us develop en]gy ( motion4 ,moreov]1 x requir$ to raise ! /one to ! ro( ! exp5diture ( an am\nt ( en]gy exactly equal to t :i* w reappe> if ! /one is all[$ to fall to ! gr\nd4 ,s 9 a *emical molecule1 l fat1 !re is a /ore ( pot5tial en]gy :i* may be made active by simply break+ ! molecule to pieces & sett+ x free4 ,?is occurs :5 ! fat burns & ! en]gy is lib]at$ z heat4 ,b x requir$ at "s "t ! exp5diture ( an equal am\nt ( en]gy to make ! molecule4 ,:5 ! molecule ( fat 0 built 9 ! plant :i* produc$ x1 !re 0 us$ 9 its con/ruction an am\nt ( sol> en]gy exactly equival5t to ! en]gy :i* may be lib]at$ by break+ ! molecule to pieces4 ,! total sum ( ! active & pot5tial en]gy 9 ! univ]se is ?us at all times ! same4 ,?is magnific5t conception has become ! corn]/one ( mod]n sci5ce4 ,z soon z conceiv$ x br\ght at once )9 its grasp all =ms ( en]gy 9 nature4 ,x is prim>ily a physical doctr9e1 & has be5 develop$ *iefly 9 connection ) ! physical sci5ces4 ,b x %[s at once a possible connection betwe5 liv+ & non-liv+ nature4 ,! liv+ organism also exhibits motion & heat1 &1 if ! doctr9e ( ! cons]vation ( en]gy be true1 ?is en]gy mu/ be correlat$ ) o!r =ms ( en]gy4 ,"h is a sugge/ion t ! same laws control ! liv+ & ! non-liv+ _w2 & a suspicion t if we c f9d a natural explanation ( ! burn+ ( a piece ( coal & ! motion ( a locomotive1 s1 too1 we may f9d a natural explanation ( ! motion ( a liv+ ma*9e4 ,evolution--,a second conception1 ^: influ5ce ^u-! developm5t ( biology 0 ev5 great]1 0 ! doctr9e ( evolution4 ,x is true t ! doctr9e ( evolution 0 no new doctr9e ) ! middle ( ?is c5tury1 = x _h be5 conceiv$ some:at vaguely be=e4 ,b until hi/orical geology _h be5 =mulat$1 & until ! idea ( ! unity ( nature _h dawn$ ^u ! m9ds ( sci5ti/s1 ! doctr9e ( evolution _h little significance4 ,x made little diff]5ce 9 our philosophy :e!r ! liv+ organisms 7 reg>d$ z indep5d5t creations or z desc5d$ f ea* o!r1 s long z !y 7 look$ ^u z a di/9ct realm ( nature )\t connection ) ! re/ ( nature's activity4 ,if !y are di/9ct f ! re/ ( nature1 & !re=e require a di/9ct orig91 x makes little diff]5ce :e!r we look$ ^u t orig9 z a s+le orig9at+ po9t or z ?\s&s ( indep5d5t creations4 ,b s soon z x appe>$ t ! pres5t condition ( ! e>?'s cru/ 0 =m$ by ! action ( =ces /ill 9 exi/5ce1 & s soon z x appe>$ t ! =ces outside ( liv+ =ces1 includ+ a/ronomical1 physical & *emical =ces1 are all correlat$ ) ea* o!r z p>ts ( ! same /ore ( en]gy1 !n ! problem ( ! orig9 ( liv+ ?+s assum$ a new mean+4 ,liv+ ?+s became !n a "p ( nature1 & dem&$ to be includ$ 9 ! same g5]al category4 ,! reign ( law1 :i* 0 claim+ t all nature's ph5om5a are ! result ( natural r ?an sup]natural p[]s1 dem&$ "s explanation ( ! orig9 ( liv+ ?+s4 ,consequ5tly1 :5 ,d>w9 po9t$ out a possible way 9 :i* liv+ ph5om5a c\ld ?us be includ$ 9 ! realm ( natural law1 sci5ce 0 ready & anxi\s to receive 8 explanation4 ,cytology4--,a ?ird conception :i* contribut$ to ! =mulation ( mod]n biology 0 d]iv$ f ! facts discov]$ 9 connection ) ! organic cell & protoplasm4 ,! significance ( ^! facts we %all notice lat]1 b "h we may simply /ate t ^! discov]ies (f]$ to /ud5ts simplicity 9 ! place ( complexity4 ,! doctr9e ( cells & protoplasm appe>$ to (f] to biologi/s no long] ! complicat$ problems :i* 7 associat$ ) animals & plants1 b ! same problems /ripp$ ( all side issues & r$uc$ to _! l[e/ t]ms4 ,?is simplify+ ( ! problems prov$ to be an extraord9>y /imulus to ! /ud5ts :o 7 try+ to f9d "s way ( und]/&+ life4 ,new ,aspects ( ,biology4--,^! ?ree conceptions seiz$ hold ( ! sci5tific _w at p]iods n v di/ant f ea* o!r1 & _! influ5ce ^u ! /udy ( liv+ nature 0 imm$iate & extraord9>y4 ,liv+ ?+s n[ came to be look$ ^u n simply z objects to be catalogu$1 b z objects :i* _h a hi/ory1 & a hi/ory :i* 0 ( int]e/ n m]ely 9 itself1 b z a "p ( a g5]al plan4 ,!y 7 no long] /udi$ z /ation>y1 b z mov+ phases ( nature4 ,animals 7 no long] look$ ^u simply z be+s n[ exi/+1 b z ! results ( ! action ( pa/ =ces & z ! f\ndation ( a diff]5t s]ies ( be+s 9 ! future4 ,! pres5t exi/+ animals & plants came to be reg>d$ simply z a /ep 9 ! long hi/ory ( ! univ]se4 ,x appe>$ at once t ! /udy ( ! pres5t =ms ( life w\ld (f] u a means ( int]pret+ ! pa/ & p]haps pr$ict+ ! future4 ,9 a %ort "t ! entire attitude :i* ! /ud5t assum$ t[>d liv+ ph5om5a _h *ang$4 ,biological sci5ce assum$ new guises & adopt$ new me?ods4 ,ev5 ! problems :i* x tri$ to solve 7 radically *ang$4 ,hi!rto ! attempt _h be5 made to f9d in/ances ( purpose 9 nature4 ,! m>vell\s adaptations ( liv+ be+s to _! conditions _h long be5 felt1 & ! /udy ( ! purposes ( ^! adaptations _h inspir$ _m a magnific5t conception4 ,b n[ ! sci5ti/ lo/ sight ( ! purpose 9 hunt+ = ! cause4 ,natural law is bl9d & c h no purpose4 ,to ! sci5ti/1 fill$ ) ! ?\ght ( ! reign ( law1 purpose c\ld n exi/ 9 nature4 ,only cause & effect appeal to him4 ,! pres5t ph5om5a are ! result ( =ces act+ 9 ! pa/1 & ! sci5ti/'s se>* %\ld be n = ! purpose ( an adaptation1 b = ! action ( ! =ces :i* produc$ x4 ,to discov] ! =ces & laws :i* l$ to ! developm5t ( ! pres5t =ms ( animals & plants1 to expla9 ! me?od by :i* ^! =ces ( nature h act$ to br+ ab\t pres5t results1 ^! became ! objects ( sci5tific rese>*4 ,x no long] _h any mean+ to f9d t a special organ 0 adapt$ to its conditions2 b x 0 necess>y to f9d out h[ x became adapt$4 ,! diff]5ce 9 ! attitude ( ^! two po9ts ( view is _w-wide4 ,! =m] fixes ! att5tion ^u ! end1 ! latt] ^u ! means by :i* ! end 0 atta9$2 ! =m] is :at we sometimes call teleological1 ! latt] sci5tific2 ! =m] 0 ! attitude ( ! /udy ( animals & plants be=e ! middle ( ?is c5tury1 ! latt] ! _s :i* actuates mod]n biology4 ,! ,me*anical ,nature ( ,liv+ ,organisms4--,?is new attitude =c$ _m new problems to ! front4 ,=emo/ among !m & fundam5tal to !m all 7 ! que/ions z to ! me*anical nature ( liv+ organisms4 ,! law ( ! correlation ( =ce told t ! v>i\s =ms ( en]gy :i* appe> ar\nd u--light1 heat1 electricity1 etc4--are all p>ts ( "o common /ore ( en]gy & conv]tible into ea* o!r4 ,! "q :e!r vital en]gy is 9 l mann] correlat$ ) o!r =ms ( en]gy 0 n[ extremely significant4 ,liv+ =ces _h be5 consid]$ z /&+ ap>t f ! re/ ( nature4 ,vital =ce1 or vitality1 _h be5 ?\ght ( z some?+ di/9ct 9 itself2 & t !re 0 any measurable relation betwe5 ! p[]s ( ! liv+ organism & ! =ces ( heat & *emical aff9ity 0 ( c\rse un?9kable be=e ! =mulation ( ! doctr9e ( ! correlation ( =ces4 ,b z soon z t doctr9e 0 und]/ood x began to appe> at once t1 to a c]ta9 ext5t at lea/1 ! liv+ body might be comp>$ to a ma*9e ^: function is simply to conv]t "o k9d ( en]gy into ano!r4 ,a /eam eng9e is f$ ) fuel4 ,9 t fuel is a /ore ( en]gy deposit$ !re p]haps c5turies ago4 ,! rays ( ! sun1 %9+ on ! _w 9 e>li] ages1 7 seiz$ ^u by ! gr[+ plants & /or$ away 9 a pot5tial =m 9 ! wood :i* lat] became coal4 ,?is coal is plac$ 9 ! furnace ( ! /eam eng9e & is brok5 to pieces s t x c no long] hold its /ore ( en]gy1 :i* is at once lib]at$ 9 its active =m z heat4 ,! eng9e !n takes ! en]gy ?us lib]at$1 & z a result ( its peculi> me*anism conv]ts x into ! motion ( its great fly-:eel4 ,) ?is notion cle>ly 9 m9d ! "q =ces itself to ! front :e!r ! same facts are n true ( ! liv+ animal organism4 ,x1 too1 is f$ ) food conta9+ a /ore ( en]gy2 & %\ld we n reg>d x1 l ! /eam eng9e1 simply a ma*9e = conv]t+ ?is pot5tial en]gy into motion1 heat1 or "s o!r active =m8 ,?is problem ( ! correlation ( vital & physical =ces is inevitably =c$ ^u u ) ! doctr9e ( ! correlation ( =ces4 ,pla9ly1 h[ev]1 su* que/ions 7 inconceivable be=e ab\t ! middle ( ! n9ete5? c5tury4 ,?is me*anical conception ( liv+ activity 0 c>ri$ ev5 f>!r4 ,"u ! lead ( ,huxley !re arose 9 ! sev5? decade ( ! c5tury a view ( life :i* r$uc$ x to a pure me*anism4 ,! microscope _h1 at t "t1 j disclos$ ! univ]sal pres5ce 9 liv+ ?+s ( t wond]ful sub/ance1 protoplasm4 ,?is mat]ial appe>$ to be a homog5e\s sub/ance1 & a *emical /udy %[$ x to be made ( *emical elem5ts unit$ 9 su* a way z to %[ close relation to album5s4 ,x appe>$ to be some:at m complex ?an ord9>y album51 b x 0 look$ ^u z a def9ite *emical comp\nd1 or1 p]haps1 z a simple mixture ( comp\nds4 ,*emi/s _h %[n t ! prop]ties ( comp\nds v>y ) _! composition1 & t ! m complex ! comp\nd ! m v>i$ its prop]ties4 ,x 0 a natural conception1 !re=e1 t protoplasm 0 a complex *emical comp\nd1 & t its vital prop]ties 7 simply ! *emical prop]ties result+ f its composition4 ,j z wat] possesses ! p[] ( becom+ solid at c]ta9 temp]atures1 s protoplasm possesses ! p[] ( assimilat+ food & gr[+2 &1 s9ce we d n d\bt t ! prop]ties ( wat] are ! result ( its *emical composition1 s we may also assume t ! vital prop]ties ( protoplasm are ! result ( its *emical composition4 ,x foll[$ f ?is conclusion t if *emi/s ev] succe$$ 9 manufactur+ ! *emical comp\nd1 protoplasm1 x w\ld be alive4 ,vital ph5om5a 7 ?us r$uc$ to *emical & me*anical problems4 ,^! ideas arose %ortly aft] ! middle ( ! c5tury1 & h dom9at$ ! developm5t ( biological sci5ce up to ! pres5t "t4 ,x is evid5t t ! aim ( biological /udy mu/ be to te/ ^! conceptions & c>ry !m out into details4 ,! *emical & me*anical laws ( nature mu/ be appli$ to vital ph5om5a 9 ord] to see :e!r !y c furni% a satisfactory explanation ( life4 ,are ! laws & =ces ( *emi/ry suffici5t to expla9 dige/ion8 ,are ! laws ( electricity applicable to an und]/&+ ( n]v\s ph5om5a8 ,are physical & *emical =ces toge!r suffici5t to expla9 life8 ,c ! animal body be prop]ly reg>d$ z a ma*9e controll$ by me*anical laws8 ,or1 on ! o!r h&1 are !re "s phases ( life :i* ! =ces ( *emi/ry & physics _c acc\nt =8 ,are !re limits to ! application ( natural law to expla9 life8 ,c !re be f\nd some?+ connect$ ) liv+ be+s :i* is =ce b n correlat$ ) ! ord9>y =ms ( en]gy8 ,is !re su* a ?+ z vital en]gy1 or is ! s-call$ vital =ce simply a "n :i* we h giv5 to ! peculi> manife/ations ( ord9>y en]gy z %[n 9 ! sub/ance protoplasm8 ,^! are "s ( ! que/ions t mod]n biology is try+ to answ]1 & x is ! exi/5ce ( su* que/ions :i* has made mod]n biology a new sci5ce4 ,su* que/ions n only did n1 b c\ld n1 h aris5 be=e ! doctr9es ( ! cons]vation ( en]gy & evolution _h made _! impression ^u ! ?\ght ( ! _w4 ,significance ( ! ,new ,biological ,problems--,x is fur!r evid5t t ! answ]s to ^! que/ions w h a significance rea*+ beyond ! doma9 ( biology prop] & affect+ ! fundam5tal philosophy ( nature4 ,! answ] w det]m9e :e!r or n we c accept 9 entirety ! doctr9es ( ! cons]vation ( en]gy & evolution4 ,pla9ly if x %\ld be f\nd t ! en]gy ( animate nature 0 n correlat$ ) o!r =ms ( en]gy1 ?is w\ld dem& ei!r a rejection or a complete modification ( our doctr9e ( ! cons]vation ( en]gy4 ,if an animal c create any en]gy )9 itself1 or c de/roy any en]gy1 we c no long] reg>d ! am\nt ( en]gy ( ! univ]se z con/ant4 ,ev5 if t subtile =m ( =ce :i* we call n]v\s en]gy %\ld prove to be uncorrelat$ ) o!r =ms ( en]gy1 ! idea ( ! cons]vation ( en]gy mu/ be *ang$4 ,x is ev5 possible t we mu/ insi/ t ! /ill m subtile =m ( =ce1 m5tal =ce1 mu/ be br\ght )9 ! scope ( ?is great law 9 ord] t x be implicitly accept$4 ,?is law has prov$ itself /rictly applicable to ! inanimate _w1 & has !n ?ru/ ^u u ! v>i\s que/ions 9 reg>d to vital =ce1 & we mu/ recognize t ! real significance ( ?is great law mu/ re/ ^u ! possibility ( its application to vital ph5om5a4 ,no less intimate is ! relation ( ^! problems to ! doctr9e ( evolution4 ,evolution tries to acc\nt = ea* mom5t 9 ! hi/ory ( ! _w z ! result ( ! conditions ( ! mom5t be=e4 ,su* a !ory loses its mean+ unless x c be %[n t natural =ces are suffici5t to acc\nt = liv+ ph5om5a4 ,if ! sup]natural mu/ be br\ght 9 "h & !re to acc\nt = liv+ ph5om5a1 !n evolution ceases to h mu* mean+4 ,x is und\bt$ly a fact t ! rapidly develop+ ideas along ! above m5tion$ l9es ( dynamical biology h1 be5 pot5t factors 9 br++ ab\t ! adoption ( evolution4 ,c]ta9 x is t1 _h x be5 f\nd t no correlation c\ld be trac$ betwe5 vital & non-vital =ces1 ! doctr9e ( evolution c\ld n h /ood1 & ev5 n[ ! special significance :i* we %all 9 ! end give to evolution w dep5d ^u h[ we succe$ 9 answ]+ ! que/ions above outl9$4 ,! fact is t ?is problem ( ! me*anical explanation ( vital ph5om5a =ms ! cap/one ( ! ar*1 ! sides ( :i* are built ( ! doctr9es ( ! cons]vation ( en]gy & ! !ory ( evolution4 ,to ! pres5tation ( ^! problems ! foll[+ pages w be devot$4 ,! fact t bo? ! doctr9e ( ! cons]vation ( en]gy & t ( evolution are practically ev]y:]e accept$ indicates t ! me*anical nature ( vital =ces is reg>d$ z prov$4 ,b !re are /ill _m que/ions :i* are n s easily answ]$4 ,x w be our purpose 9 ! foll[+ discussion to asc]ta9 j :at are ^! problems 9 dynamical biology & h[ f> !y h be5 answ]$4 ,our object w be !n 9 brief to discov] to :at ext5t ! conception ( ! liv+ organism z a ma*9e is borne out by ! facts :i* h be5 collect$ 9 ! la/ qu>t] c5tury1 & to le>n :]e1 if any:]e1 limits h be5 f\nd to our possibility ( apply+ ! =ces ( *emi/ry & physics to an explanation ( life4 ,9 o!r words1 we %all try to see h[ f> we h be5 able to und]/& liv+ ph5om5a 9 t]ms ( natural =ce4 ,outl9e ( ! ,subject4--,! subject1 z ?us pres5t$1 resolves itself at once into two p>ts4 ,t ! liv+ organism is a ma*9e is ev]y:]e recogniz$1 al?\gh "s may /ill d\bt z to ! complet5ess ( ! comp>ison4 ,9 ! attempt to expla9 ! ph5om5a ( life we h two entirely diff]5t problems4 ,! fir/ is manife/ly to acc\nt = ! exi/5ce ( ?is ma*9e1 = su* a complet$ piece ( me*anism z a man or a tree _c be expla9$ z a result ( simple accid5t1 z ! exi/5ce ( a r\gh piece ( rock might be expla9$4 ,its intricacy ( p>ts & _! purposeful int]relation dem&s explanation1 & !re=e ! fundam5tal problem is to expla9 h[ ?is ma*9e came into exi/5ce4 ,! second problem is simpl]1 = x is simply to expla9 ! runn+ ( ! ma*9e aft] x is made4 ,if ! organism is really a ma*9e1 we ought to be able to f9d "s way ( expla9+ its actions z we c ^? ( a /eam eng9e4 ,( ^! two problems ! fir/ is ! m fundam5tal1 = if we fail to f9d an explanation = ! exi/5ce ( ! ma*9e1 our explanation ( its me?od ( action is only p>tly satisfactory4 ,b ! second "q is ! simpl]1 & mu/ be answ]$ fir/4 ,we _c hope to expla9 ! m puzzl+ matt] ( ! orig9 ( ! ma*9e unless we c fir/ und]/& h[ x acts4 ,9 our treatm5t ( ! subject1 !re=e1 we %all divide x into two p>ts3 ,i4 ,! ,runn+ ( ! ,liv+ ,ma*9e4 ,,ii4 ,! ,orig9 ( ! ,liv+ ,ma*9e4 ,,"p ,i4 ,,! ,,runn+ ,,( ,,! ,,liv+ ,,ma*9e4 99 99 99 99 99 ,,*apt] ,i4 ,,is ,,! ,,body ,a ,,ma*9e8 ,! problem be=e u 9 ?is section is to f9d out to :at ext5t animals & plants are ma*9es4 ,we wi% to det]m9e :e!r ! laws & =ces :i* regulate _! activities are ! same z ! laws & =ces ) :i* we exp]im5t 9 ! *emical & physical laboratory1 & :e!r ! pr9ciples ( me*anics & ! doctr9e ( ! cons]vation ( en]gy apply equally well 9 ! liv+ ma*9e & ! /eam eng9e4 ,x might be inf]r$ t ! prop] me?od ( /udy w\ld be to conf9e our att5tion l>gely to ! simple/ =ms ( life1 s9ce ! problems w\ld be "h less complicat$1 & !re=e ( easi] solution4 ,?is1 h[ev]1 has n be5 nor c x be ! me?od ( /udy4 ,our k ( ! processes ( life h be5 d]iv$ l>gely f ! mo/ r ?an ! lea/ complex =ms4 ,we h a bett] k ( ! physiology ( man & 8 allies ?an any o!r animals4 ,! reason = ?is is pla9 en\gh4 ,9 ! fir/ place1 !re is a value 9 ! k ( ! life activities ( man entirely ap>t f any !oretical aspects1 & h5ce human physiology has dem&$ att5tion = its own sake4 ,! practical utility ( human physiology has /imulat$ its /udy = c5turies2 & 9 ! la/ fifty ye>s ( sci5tific progress x has be5 human physiology & t ( alli$ animals t has attract$ ! *ief att5tion ( physiologi/s4 ,! result is t :ile ! physiology ( man is tol]ably well kn[n1 t ( o!r animals is less und]/ood ! f>!r we get away f man & 8 allies4 ,= ?is reason mo/ ( our k ( ! liv+ body z a ma*9e mu/ be d]iv$ f ! /udy ( man4 ,?is is1 h[ev]1 =tunate r ?an o!rwise4 ,9 ! fir/ place1 x enables u to proce$ f ! kn[n to ! unkn[n2 & 9 ! second place1 m int]e/ atta*es to ! problem z connect$ ) human physiology ?an along any o!r l9e4 ,9 our discussion1 !re=e1 we %all ref] *iefly to ! physiology ( man4 ,if we f9d t ! functions ( human life are am5able to a me*anical explanation we _c hesitate to believe t ?is w be equally true ( ! l[] ord]s ( nature4 ,= simil> reasons little ref]5ce w be made to ! me*anism ( plant life4 ,! /ructure ( ! plant is simpl] & its activities are mu* m easily ref]able to me*anical pr9ciples ?an are ^? ( animals4 ,= ^! reasons x w only be necess>y = u to turn our att5tion to ! life activities ( ! high] animals4 ,:at is a ,ma*9e8--,turn+ n[ to our m imm$iate subject ( ! accuracy ( ! /atem5t t ! body is a ma*9e1 we mu/ fir/ ask :at is meant by a ma*9e8 ,a brief def9ition ( a ma*9e might be z foll[s3 ,a ma*9e is a piece ( app>atus s design$ t x c *ange "o k9d ( en]gy into ano!r = a def9ite purpose4 ,en]gy1 z already notic$1 is ! p[] ( do+ "w1 & its ord9>y active =ms are heat1 motion1 electricity1 light1 etc42 b x may be 9 a passive or pot5tial =m1 & 9 ?is =m /or$ )9 a *emical molecule4 ,^! v>i\s =ms ( en]gy are readily conv]tible into ea* o!r2 & any =m ( app>atus design$ = ! purpose ( produc+ su* a conv]sion is call$ a ma*9e4 ,a dynamo is ?us a ma*9e s adju/$ t :5 me*anical motion is suppli$ to x ! en]gy ( motion is conv]t$ into electricity2 :ile an electromotor1 on ! o!r h&1 is a piece ( app>atus s design$ t :5 electricity is appli$ to x1 x is conv]t$ into motion4 ,a /eam eng9e1 aga91 is design$ to conv]t pot5tial or passive en]gy into active en]gy4 ,pot5tial en]gy 9 ! =m ( *emical composition 7coal7 is suppli$ to ! eng9e1 & ?is en]gy is fir/ lib]at$ 9 ! active =m ( heat & !n is conv]t$ into ! motion ( ! great fly-:eel4 ,9 all ^! cases !re is no en]gy or p[] creat$1 = ! ma*9e mu/ be always suppli$ ) an am\nt ( en]gy equal to t :i* x gives back 9 ano!r =m4 ,inde$1 a l>g] am\nt ( en]gy mu/ be furni%$ ! ma*9e ?an is expect$ back1 = !re is always an actual loss ( available en]gy4 ,9 ! process ( ! conv]sion ( "o =m ( en]gy into ano!r "s ( ! en]gy1 f friction or o!r cause1 takes ! =m ( heat1 & is !n radiat$ into space beyond our rea*4 ,x is1 ( c\rse1 n de/roy$1 = en]gy _c be de/roy$2 b x has assum$ a =m call$ radiant heat1 :i* is n available = our uses4 ,a ma*9e ?us nei!r creates nor de/roys en]gy4 ,x receives x 9 "o =m & gives x back 9 ano!r =m1 ) an inevitable loss ( a portion ( ! en]gy z radiant heat4 ,) ?is und]/&+1 we may n[ ask if ! liv+ body c be prop]ly comp>$ ) a ma*9e4 ,a ,g5]al ,comp>ison ( a ,body & a ,ma*9e4--,t ! liv+ body exhibits ! ord9>y types ( en]gy is ( c\rse cle> en\gh :5 we rememb] t x is always 9 motion & is always radiat+ heat--two ( ! mo/ common types ( physical en]gy4 ,t ?is en]gy is suppli$ to ! body z x is to o!r ma*9es1 9 ! =m ( ! en]gy ( *emical composition1 w also ne$ no fur!r pro( :5 x is rememb]$ t x is necess>y to supply ! body ) appropriate food 9 ord] t x may d "w4 ,! food we eat1 l coal1 repres5ts s mu* sol> en]gy :i* is /or$ up by ! ag5cy ( plant life1 & ! close comp>ison betwe5 fe$+ ! body to enable x to "w & fe$+ ! eng9e to enable x to develop en]gy is s evid5t t x dem&s no fur!r demon/ration4 ,! details ( ! problem may1 h[ev]1 pres5t "s difficulties4 ,! fir/ "q :i* pres5ts itself is :e!r ! only p[] ! body possesses is1 z 9 ! case ) o!r ma*9es1 to trans=m en]gy )\t be+ able to create or de/roy x8 ,c e bit ( en]gy %[n by ! liv+ organism be acc\nt$ = by en]gy furni%$ 9 ! food1 & conv]sely c all ! en]gy furni%$ 9 ! food be f\nd manife/$ 9 ! liv+ organism8 ,! !oretical answ] to ?is "q 9 t]ms ( ! law ( ! cons]vation ( en]gy is cle> en\gh1 b x is by no means s easy to answ] x by exp]im5tal data4 ,to obta9 exp]im5tal demon/ration x w\ld be necess>y to make an accurate det]m9ation ( ! am\nt ( en]gy an individual receives dur+ a giv5 p]iod1 & at ! same "t a simil> measurem5t ( ! am\nt ( en]gy lib]at$ 9 8 body ei!r z motion or heat4 ,if ! body is a ma*9e1 ^! two %\ld exactly balance1 & if !y d n balance x w\ld indicate t ! liv+ organism ei!r creates or de/roys en]gy1 & is !re=e n a ma*9e4 ,su* exp]im5ts are exce$+ly difficult4 ,!y mu/ be p]=m$ usually ^u man r ?an o!r animals1 & x is necess>y to inclose an individual 9 an absolutely seal$ space ) arrangem5ts = furni%+ him ) air & food 9 measur$ quantity1 & ) appliances = measur+ accurately ! "w he does & ! heat giv5 (f f 8 body4 ,9 addition1 x is necess>y to measure ! exact am\nt ( mat]ial he elim9ates 9 ! =m ( c>bonic acid & o!r excretions4 ,su* exp]im5ts pres5t _m difficulties :i* h n yet be5 ?or\ghly ov]come1 b !y h be5 attempt$ by sev]al inve/igators4 ,= ! purpose ( su* an exp]im5t sci5ti/s h all[$ !mselves to be %ut up 9 a small *amb] six or eight feet 9 l5g?1 9 :i* _! only communication ) ! out] _w is by telephone & ?r\gh a small op5+ 9 ! side ( ! *amb]1 occasionally op5$ = a second or two to supply ! prison] ) food4 ,9 su* a *amb] !y h rema9$ z long z twelve days4 ,9 ^! exp]im5ts x is necess>y to take acc\nt n only ( ! food eat51 b ( ! actual am\nt ( ?is food :i* is us$ by ! body4 ,if ! p]son ga9s 9 weight1 ?is mu/ mean t he is /or+ up 9 8 body mat]ial = future use2 :ile if he loses 9 weight1 ?is means t he is consum+ 8 own tissues = fuel4 ,c>eful daily records ( 8 weight mu/ !re=e be tak54 ,e/imates ( ! solids1 liquids1 & gases giv5 (f f 8 body mu/ be obta9$1 = to c>ry out ! exp]im5t an exact balance mu/ be made betwe5 ! income & ! outgo4 ,! app>atus devis$ = su* exp]im5ts has be5 made v delicate2 s delicate1 inde$1 t ! ris+ ( ! individual 9 ! box f 8 *air is imm$iately se5 9 a rise 9 temp]ature ( ! app>atus4 ,b ev5 ) ?is delicacy ! app>atus is comp>atively co>se1 & c measure only ! mo/ app>5t =ms ( en]gy4 ,! m subtle types ( en]gy1 su* z n]v\s =ce1 if ?is is to be reg>d$ z en]gy1 d n make any impression on ! app>atus4 ,! ob/acles 9 ! way ( ^! exp]im5ts d n p>ticul>ly conc]n u1 b ! g5]al results are ( ! greate/ significance = our purpose4 ,:ile1 = manife/ reasons1 x has n be5 possible to c>ry on ^! exp]im5ts = any great l5g? ( "t1 & :ile ! results h n yet be5 v accurately ref9$1 !y are all ( "o k9d & tea* unhesitat+ly "o conclusion4 ,s f> z conc]ns measurable en]gy or measurable mat]ial1 ! body behaves j l any o!r ma*9e4 ,if ! body is to d "w 9 ?is respiration app>atus1 x does s only by break+ to pieces a c]ta9 am\nt ( food & us+ ! en]gy ?us lib]at$1 & ! am\nt ( food ne$$ is proportional to ! am\nt ( "w done4 ,:5 ! individual simply walks across ! floor1 or ev5 rises f 8 *air1 ?is is accompani$ by an increase 9 ! am\nt ( food mat]ial brok5 up & a consequ5t increase 9 ! am\nt ( refuse matt] elim9at$ & ! heat giv5 (f4 ,! income & outgo ( ! body 9 bo? matt] & en]gy is balanc$4 ,if1 dur+ ! exp]im5tal p]iod1 x is f\nd t less en]gy is lib]at$ ?an t conta9$ 9 ! food assimilat$1 x is also f\nd t ! body has ga9$ 9 weight1 :i* simply means t ! extra en]gy has be5 /or$ 9 ! body = future use4 ,no m en]gy c be obta9$ f ! body ?an is furni%$1 & = all furni%$ 9 ! food an equival5t am\nt is rega9$4 ,!re is no trace ( any creation or de/ruction ( en]gy4 ,:ile1 on acc\nt ( ! complexity ( ! exp]im5t+1 an absolutely /rict balance %eet _c be made1 all ! results are ( ! same nature4 ,s f> z conc]ns measurable en]gy1 all ! facts collect$ be> out ! !oretical conception t ! liv+ body is to be reg>d$ z a ma*9e :i* conv]ts ! pot5tial en]gy ( *emical composition1 /or$ passively 9 its food1 into active en]gy ( motion & heat4 ,x is f\nd1 h[ev]1 t ! body is a ma*9e ( a some:at sup]ior grade1 s9ce x is able to conv]t ?is pot5tial en]gy into motion ) less loss ?an ! ord9>y ma*9e4 ,z notic$ above1 9 all ma*9es a portion ( ! en]gy is conv]t$ into heat & r5d]$ unavailable by radiat+ into space4 ,9 an ord9>y eng9e only ab\t "o-fifte5? ( ! en]gy furni%$ 9 ! coal c be rega9$ 9 ! =m ( motive p[]1 ! re/ be+ radiat$ f ! ma*9e z heat4 ,"s ( our bett] eng9es to-day utilize a some:at l>g] "p1 b mo/ ( !m utilize less ?an "o-t5?4 ,! exp]im5ts ) ! liv+ body 9 ! respiration app>atus above describ$1 give a means ( det]m9+ ! proportion ( ! en]gy furni%$ 9 ! =m ( food :i* c be utiliz$ 9 ! =m ( motive =ce4 ,?is figure appe>s to be decid$ly l>g] ?an t obta9$ by any ma*9e yet devis$ by man4 ,! conclusion ( ! matt] up to ?is po9t is !n cle>4 ,if we leave out ( acc\nt ! ph5om5a ( ! n]v\s sy/em1 :i* we %all consid] pres5tly1 ! g5]al income & outgo ( ! body z conc]ns matt] & en]gy is su* t ! body mu/ be reg>d$ z a ma*9e1 :i*1 l o!r ma*9es1 simply trans=ms en]gy )\t creat+ or de/roy+ x4 ,to ?is ext5t1 at lea/1 animals con=m to ! law ( ! cons]vation ( en]gy & are v]itable ma*9es4 ,details ( ! ,action ( ! ,ma*9e4--,we turn next to "s ( ! subord9ate problems conc]n+ ! details ( ! action ( ! liv+ ma*9e4 ,we h a cle> und]/&+ ( ! me?od ( action ( a /eam eng9e4 ,its me*anism is simple1 &1 moreov]1 x 0 design$ by human intellig5ce4 ,we c und]/& h[ ! =ce ( *emical aff9ity breaks up ! *emical composition ( ! coal1 h[ ! heat ?us lib]at$ is appli$ to ! wat] to vap\rize x2 h[ ! vap\r is collect$ 9 ! boil] "u pressure2 h[ ?is pressure is appli$ to ! pi/on 9 ! cyl9d]1 & h[ ?is f9ally results 9 ! revolution ( ! fly-:eel4 ,x is true t we d n und]/& ! und]ly+ =ces ( *emism1 etc41 b ^! =ces c]ta9ly exi/ & are ! f\ndation ( sci5ce4 ,b ! me*anism ( ! eng9e is intelligible4 ,our und]/&+ ( x is su* t1 ) ! =ces ( *emi/ry & physics z a f\ndation1 we c readily expla9 ! runn+ ( ! ma*9e4 ,our next problem1 !re=e1 is to see if we c 9 ! same way rea* an und]/&+ ( ! ph5om5a ( ! liv+ ma*9e4 ,c we1 by ! use ( ^! same *emical & physical =ces1 expla9 ! activities tak+ place 9 ! liv+ organism8 ,c ! motion ( ! body1 = example1 be made z intelligible z ! motion ( ! /eam eng9e8 ,physical ,explanation ( ! ,*ief ,vital ,functions4--,! liv+ ma*9e is1 ( c\rse1 va/ly m complicat$ ?an ! /eam eng9e1 & !re are _m diff]5t processes :i* mu/ be consid]$ sep>ately4 ,!re is n space 9 a "w ( ?is size to consid] !m all c>efully1 b we may select a few ( ! vital functions z illu/rations ( ! me?od :i* is pursu$4 ,x w be assum$ t ! fundam5tal processes ( human physiology are und]/ood by ! read]1 & we %all try to int]pret "s ( !m 9 t]ms ( *emical & physical =ce4 ,dige/ion4--,! fir/ /ep 9 ?is trans=mation ( fuel is ! process ( dige/ion4 ,n[ ?is process ( dige/ion is no?+ my/]i\s1 nor does x involve any peculi> or special =ces4 ,dige/ion ( food is simply a *emical *ange !re94 ,! food :i* is tak5 into ! body 9 ! =m ( sug>1 />*1 fat or prote91 is act$ ^u by ! dige/ive juices 9 su* a way t its *emical nature is slightly *ang$4 ,b ! *anges t ?us occur are n peculi> to ! liv+ body1 s9ce !y w take place equally well 9 ! *emi/'s laboratory4 ,!y are simply *anges 9 ! molecul> /ructure ( ! food mat]ial1 & only su* *anges z are simple & famili> to ! *emi/4 ,! =ces :i* effect ! *ange are und\bt$ly ^? ( *emical aff9ity4 ,! only feature ( ! process :i* is n p]fectly intelligible 9 t]ms ( *emical law is ! nature ( ! dige/ive juices4 ,! dige/ive fluids ( ! m\? & /oma* conta9 c]ta9 sub/ances :i* possess a some:at rem>kable p[]1 inasmu* z !y are able to br+ ab\t ! *emical *anges :i* occur 9 ! dige/ion ( food4 ,an example w make ?is cle>]4 ,"o ( ! dige/ive processes is ! conv]sion ( />* into sug>4 ,! relation ( ^! two bodies is a v simple "o1 />* be+ readily conv]t$ into sug> by ! addition to its molecule ( a molecule ( wat]4 ,! *ange c n be produc$ by simply add+ />* to wat]1 b ! wat] mu/ be introduc$ into ! />* molecule4 ,?is *ange c be br\ght ab\t 9 a v>iety ( ways1 & is und\bt$ly effect$ by ! =ces ( *emical aff9ity4 ,*emi/s h f\nd simple me?ods ( produc+ ?is *emical union1 & ! manufacture ( sug> out ( />*y mat]ial has ev5 become some?+ ( a comm]cial indu/ry4 ,"o ( ! me?ods by :i* ?is *ange c be produc$ is by add+ to ! />*1 along ) "s wat]1 a little saliva4 ,! saliva has ! p[] ( caus+ ! *emical *ange to occur at once1 & ! molecule ( wat] ent]s into ! />* molecule & =ms sug>4 ,n[ we d n und]/& h[ ?is saliva possesses ?is p[] to induce ! *emical *ange4 ,b app>5tly ! process is ( ! simple/ "* & involves no great] my/]y ?an *emical aff9ity4 ,we "k t ! saliva conta9s a c]ta9 mat]ial call$ a f]m5t1 :i* is ! active ag5t 9 br++ ab\t ! *ange4 ,?is f]m5t is n alive1 nor does x ne$ any liv+ environm5t = its action4 ,x c be sep>at$ f ! saliva 9 ! =m ( a dry amorph\s p[d]1 & 9 ?is =m c be pres]v$ almo/ indef9itely1 reta9+ its p[] to effect ! *ange :5ev] put "u prop] conditions4 ,! *ange ( />* into sug> is ?us a simple *emical *ange occurr+ "u ! influ5ce ( *emical aff9ity "u c]ta9 conditions4 ,"o ( ! conditions is ! pres5ce ( ?is saliva f]m5t4 ,if we c n exactly und]/& h[ ! f]m5t produces ?is action1 nei!r d we exactly und]/& h[ a sp>k causes a bit ( gunp[d] to explode4 ,b we c n d\bt t ! latt] is a purely natural result ( ! relation ( *emical & physical =ces1 & !re is no m reason = d\bt+ x 9 ! =m] case4 ,:at is true ( ! dige/ion ( />* by saliva is equally true ( ! dige/ion ( o!r foods 9 ! /oma* & inte/9e4 ,ea* ( ! dige/ive juices conta9s a f]m5t :i* br+s ab\t a *emical *ange 9 ! food4 ,! *anges are always *emical *anges & are ! result ( *emical =ces4 ,ap>t f ! pres5ce ( ^! f]m5ts !re is really little diff]5ce betwe5 laboratory *emi/ry & liv+ *emi/ry4 ,absorption ( food4--,! next function ( ?is ma*9e to attract our att5tion is ! absorption ( food f ! inte/9e into ! blood4 ,! dige/$ food is c>ri$ d[n ! alim5t>y canal 9 a purely me*anical fa%ion by muscul> action1 & :5 x rea*es ! inte/9e x beg9s to pass ?r\gh its walls into ! blood4 ,9 ?is absorption we f9d engag$ ano!r set ( =ces1 ! *ief ( :i* appe>s to be ! physical =ce ( osmosis4 ,! =ce ( osmosis has no special connection ) life4 ,if a membrane sep>ates two liquids ( diff]5t composition 7,fig4 i71 a =ce is ex]t$ on ! liquids :i* cause !m to pass ?r\gh ! membrane1 ea* pass+ ?r\gh ! membrane into ! o!r comp>tm5t4 ,! =ce :i* drives ^! liquids ?r\gh ! membrane is consid]able1 & may sometimes be ex]t$ aga9/ consid]able pressure4 ,a simple exp]im5t w illu/rate ?is =ce4 ,9 ,fig4 #b is repres5t$ a membran\s bag tightly fa/5$ to a glass tube4 ,! bag is fill$ ) a /rong solution ( sug>1 & is imm]s$ 9 a vessel conta9+ pure wat]4 ,"u ^! conditions "s ( ! sug> solution passes ?r\gh ! bag into ! wat]1 & "s ( ! wat] passes f ! vessel into ! bag4 ,b if ! solution ( sug> is inside ! bag & ! pure wat] outside1 ! am\nt ( liquid pass+ into ! bag is great] ?an ! am\nt pass+ out2 ! bag soon becomes di/5d$ & ! wat] ev5 rises 9 ! tube to a consid]able height at a7,fig4 #b74 ,! =ce "h conc]n$ is a =ce kn[n z osmosis or dialysis1 & is always ex]t$ :5 two diff]5t solutions ( c]ta9 sub/ances are sep>at$ f ea* o!r by a membrane4 ,! sub/ances 9 solution w1 "u ^! conditions1 pass f ! d5se to ! weak] solution4 ,! process is a purely physical "o4 ,illu/ration3 ,,fig4 #a4--,to illu/rate osmosis4 ,9 ! vessel ,a is a solution ( sug>2 9 ,b1 is pure wat]4 ,! two are sep>at$ by ! membrane ,c4 ,! sug> passes ?r\gh ! membrane into ,b4 ,illu/ration3 ,,fig4 #b4--;,9 ! bladd] ,a is a sug> solution4 ,9 ! vessel ,b is pure wat]4 ,sug> passes out & wat] into ! bladd] until x rises 9 ! tube to a4 ,?is process ( osmosis lies at ! basis ( ! absorption ( food f ! alim5t>y canal4 ,9 ! fir/ place1 mo/ ( ! food :5 swall[$ is n soluble1 & !re=e n capable ( osmosis4 ,b ! process ( dige/ion1 z we h se51 *anges ! *emical nature ( ! food4 ,! food1 z ! result ( *emical *ange1 has become soluble1 & aft] be+ dissolv$ x is dialyzable--i4e41 capable ( osmosis4 ,aft] dige/ion1 !re=e1 ! food is dissolv$ 9 ! liquids 9 ! /oma* & inte/9e1 & is 9 prop] condition = dialysis4 ,fur!rmore1 ! /ructure ( ! inte/9e is su* z to produce conditions adapt$ = dialysis4 ,?is c be und]/ood f ,fig4 #c1 :i* repres5ts diagrammatically a cross section ?r\gh ! inte/9al wall4 ,)9 ! inte/9al wall1 at ,a1 is ! food mass 9 solution4 ,at ,b are %[n little projections ( ! inte/9al wall1 call$ villi ext5d+ into ?is food & cov]$ by a membrane4 ,"o ( ^! villi is %[n m highly magnifi$ 9 ,fig4 #d1 9 :i* ,b %[s ?is membrane4 ,inside ( ^! villi are blood-vessels1 ,c1 & x w be ?us se5 t ! membrane1 ,b1 sep>ates two liquids1 "o conta9+ ! dissolv$ food outside ! villus1 & ! o!r conta9+ blood inside ! villus4 ,"h are prop] conditions = osmosis1 & ?is process ( dialysis w take place :5ev] ! inte/9al cont5ts holds m dialyzable mat]ial ?an ! blood4 ,"u ^! conditions1 :i* w always occur aft] food has be5 dige/$ by ! dige/ive juices1 ! food w beg9 to pass ?r\gh ?is membran\s wall ( ! inte/9e into ! blood "u ! influ5ce ( ! physical =ce ( osmosis4 ,?us ! prim>y factor 9 food absorption is a physical "o4 ,we mu/ notice1 h[ev]1 t ! physical =ce ( osmosis is n ! only factor conc]n$ 9 absorption4 ,9 ! fir/ place1 x is f\nd t ! food dur+ its passage ?r\gh ! inte/9al wall1 or %ortly aft]w>ds1 und]goes a fur!r *ange1 s t by ! "t x has fairly rea*$ ! blood x has aga9 *ang$ its *emical nature4 ,^! *anges are1 h[ev]1 ( a *emical nature1 &1 :ile we d n yet "k v mu* ab\t !m1 !y are ( ! same sort z ^? ( dige/ion1 & involve probably no?+ m ?an *emical processes4 ,illu/ration3 ,,fig4 #c--;,diagram ( ! inte/9al walls4 ,a1 lum5 ( inte/9e fill$ ) dige/$ food4 ,b1 villi1 conta9+ blood vessels4 ,c1 l>g] blood vessel1 :i* c>ries blood ) absorb$ food away f ! inte/9e4 ,secondly1 we notice t !re is "o phase ( absorption :i* is /ill obscure4 ,"p ( ! food is compos$ ( fat1 & ?is fat1 z ! result ( dige/ion1 is me*anically brok5 up into extremely m9ute droplets4 ,al?\gh ^! droplets are ( microscopic size !y are n actually 9 solution1 & !re=e n subject to ! =ce ( osmosis :i* only affects solutions4 ,! osmotic =ce w n =ce fat drops ?r\gh membranes1 & to expla9 _! passage ?r\gh ! walls ( ! inte/9e requires some?+ additional4 ,we are z yet1 h[ev]1 able to give only a p>tial explanation ( ?is matt]4 ,! inn] wall ( ! inte/9e is n an in]t1 lifeless membrane1 b is made ( active bits ( liv+ matt]4 ,^! bits ( liv+ matt] appe> to seize hold ( ! droplets ( oil by means ( little processes :i* !y ?ru/ out1 & !n pass !m ?r\gh _! own bodies to excrete !m on _! inn] surface into ! blood vessels4 ,fig4 #e %[s a few ( ^! liv+ bits ( ! membrane1 ea* conta9+ sev]al su* fat droplets4 ,?is fat absorption ?us appe>s to be a vital process1 & n "o simply controll$ by physical =ces l osmosis4 ,"h our explanation runs aga9/ :at we call vital p[] ( ! ultimate elem5ts ( ! body4 ,! consid]ation ( ?is vital feature we mu/1 ( c\rse1 inve/igate fur!r2 b ?is w be done lat]4 ,at pres5t our purpose is a g5]al comp>ison ( ! body & a ma*9e1 & we may = a little po/pone ! consid]ation ( ?is vital ph5om5on4 ,illu/ration3 ,,fig4 #d4--;,diagram ( a s+le villus enl>g$4 ,b repres5ts ! membran\s surface cov]+ ! villus2 ,c1 ! blood-vessels )9 ! villus4 ,illu/ration3 ,,fig4 #e4--;,an enl>g$ figure ( f\r cells ( ! membrane ,b 9 ,fig4 #d4 ,! free surface is at a2 f %[s fat droplets 9 process ( passage ?r\gh ! cells4 ,circulation4--,! next piece ( me*anism = u to consid] 9 ?is ma*9e is ! device = di/ribut+ ?is fuel to ! v>i\s p>ts ( ! ma*9e :]e x is to be us$ z a s\rce ( en]gy1 correspond+ 9 a s5se to ! fireman ( a locomotive4 ,?is me*anism we call ! circulatory sy/em4 ,x consi/s ( a s]ies ( tubes1 or blood vessels1 runn+ to e "p ( ! body & supply+ e bit ( tissue4 ,)9 ! tubes is ! blood1 :i*1 f its liquid nature1 is easily =c$ ar\nd ! body ?r\gh ! tubes4 ,at ! c5tre ( ! sy/em is a pump :i* keeps ! blood 9 motion4 ,! tubes =m a clos$ sy/em1 su* t ! pump1 or he>t1 may suck ! blood 9 f "o side to =ce x out into ! tubes on ! o!r side2 & ! blood1 aft] pass+ ov] ! body 9 ?is clos$ set ( tubes1 is f9ally br\ght back aga9 to be =c$ once m ov] ! same pa?4 ,z ?is blood is c>ri$ ar\nd ! body x conveys f "o "p ( ! ma*9e to ano!r all mat]ial t ne$s di/ribution4 ,:ile 9 ! inte/9e1 z already notic$ 7,fig4 #c71 x receives ! food1 & n[ ?is food is c>ri$ by ! circulation to ! muscles or ! o!r organs t ne$ x4 ,:ile 9 ! lungs ! blood receives oxyg51 & ?is oxyg5 is !n c>ri$ to ^? p>ts ( ! body t ne$ x4 ,! circulatory sy/em is ?us simply a m$ium by :i* ea* "p ( ! ma*9e may receive its prop] %>e ( ! supplies ne$$ = its action4 ,n[ 9 ?is circulation we h aga9 to d ) *emical & physical =ces4 ,all ( its g5]al ph5om5a are bas$ ^u purely me*anical pr9ciples4 ,! action ( ! he>t--leav+ out ( consid]ation = a mom5t its muscul> p[]--is t ( a simple pump4 ,x is provid$ ) valves ^: action is z simple & z easy to und]/& z ^? ( any wat] pump4 ,by ! action ( ^! valves ! blood is kept circulat+ 9 "o direction4 ,! blood vessels are ela/ic1 & ! /udy ( ! effect ( a liquid pump$ rhy?mically into ela/ic tubes expla9s ) simplicity ! v>i\s ph5om5a associat$ ) ! circulation4 ,= example1 ! rhy?mically contract+ he>t =ces a small quantity ( blood into ! art]ies at %ort int]vals4 ,^! tubes are l>ge ne> ! he>t1 b small] at _! ends1 :]e !y fl[ into ! ve9s1 s t ! blood does n fl[ out into ! ve9s s readily z x fl[s 9 f ! he>t4 ,! jet ( blood t is s5t 9 ) e beat ( ! he>t slightly /ret*es ! art]y1 & ! t5sion ?us produc$ causes ! blood to cont9ue to fl[ betwe5 ! beats4 ,b ! he>t cont9ues beat+1 & !re is an accumulation ( ! blood 9 ! art]ies until x exi/s "u "s pressure--a pressure suffici5t to =ce x rapidly ?r\gh ! small ends ( ! art]ies into ! ve9s4 ,aft] pass+ into ! ve9s ! pressure is at once remov$1 s9ce ! ve9s are l>g] ?an ! art]ies1 & !re is no resi/ance to ! fl[ ( ! blood4 ,h5ce ! blood 9 ! art]ies is "u pressure1 :ile !re is little or no pressure 9 ! ve9s4 ,into ! details ( ?is matt] we ne$ n g1 b ?is w be suffici5t to indicate t ! :ole process is a me*anical "o4 ,we mu/ n fail to see1 h[ev]1 t 9 ?is problem ( circulation !re are two po9ts at lea/ :]e once m we meet ) t class ( ph5om5a :i* we /ill call vital4 ,! beat+ ( ! he>t is ! fir/ ( ^!1 = ?is is active muscul> p[]4 ,! second is a contraction ( ! small] blood-vessels :i* regulates ! blood supply4 ,bo? ( ^! ph5om5a are phases ( muscul> activity1 & w be includ$ "u ! discussion ( o!r simil> ph5om5a lat]4 ,illu/ration3 ,,fig4 #f4--;,a bit ( muscle ) its blood-vessels3 a1 ! muscle fibres2 b1 ! m9ute blood-vessels4 ,! fibres & vessels are ba!d 9 lymph 7n %[n 9 ! figure71 & food mat]ial passes ?r\gh ! walls ( ! blood-vessels into ?is lymph4 ,we next notice t n only is ! di/ribution ( ! blood expla9$ ^u me*anical pr9ciples1 b ! supply+ ( ! active p>ts ( ! body ) food is 9 ! same way intelligible4 ,z we h se51 ! blood com+ f ! inte/9e conta9s ! food mat]ial receiv$ f ! dige/$ food4 ,n[ :5 ?is blood 9 its circulation fl[s ?r\gh ! active tissues--= in/ance1 ! muscles--x is aga9 plac$ "u conditions :]e osmosis is sure to occur4 ,9 ! muscles ! ?9-wall$ blood-vessels are surr\nd$ & ba!d by a liquid call$ lymph4 ,figure #f %[s a bit ( muscle tissue1 ) its blood-vessels1 :i* are surr\nd$ by lymph4 ,! lymph1 :i* is n %[n1 fills all ! space outside ! blood-vessels1 ?us ba?+ bo? muscles & blood-vessels4 ,"h aga9 we h a membrane 7i4e41 ! wall ( ! blood-vessel7 sep>at+ two liquids1 & s9ce ! lymph is ( a diff]5t composition f ! blood1 dialysis betwe5 !m is sure to occur1 & ! mat]ials :i* pass$ into ! blood 9 ! inte/9e ?r\gh ! influ5ce ( ! osmotic =ce1 n[ pass out into ! lymph "u ! influ5ce ( ! same =ce4 ,! food is ?us br\ght into ! lymph2 & s9ce ! lymph lies 9 actual contact ) ! liv+ muscle fibres1 ^! fibres are n[ able to take directly f ! lymph ! mat]ial ne$$ = _! use4 ,! p[] :i* enables ! muscle fibre to take ! mat]ial x ne$s1 disc>d+ ! re/1 is1 aga91 "o ( ! vital processes :i* we def] = a mom5t4 ,respiration4--,pursu+ ! same l9e ( /udy1 we turn = a mom5t to ! relation ( ! circulatory sy/em to ! function ( supply+ ! body ) oxyg5 gas4 ,oxyg5 is absolutely ne$$ to c>ry on ! functions ( life2 = ^!1 l ^? ( ! eng9e1 are bas$ ^u ! oxidation ( ! fuel4 ,! oxyg5 is d]iv$ f ! air 9 ! simple/ mann]4 ,dur+ its circulation ! blood is br\ght = a fraction ( a second into practical contact ) air4 ,?is occurs 9 ! lungs1 :]e !re are great numb]s ( air cells1 9 ! walls ( :i* ! blood-vessels are di/ribut$ 9 great pr(usion4 ,:ile ! blood is 9 ^! vessels x is n inde$ 9 actual contact ) ! air1 b is sep>at$ f x by only a v ?9 membrane--s ?9 t x =ms no h9drance to ! int]*ange ( gases4 ,^! air-cells are kept fill$ ) air by simple muscul> action4 ,by ! contraction ( ! muscles ( ! ?orax ! ?oracic cavity is enl>g$1 & z a result air is suck$ 9 9 exactly ! same way t x is suck$ into a pair ( bell[s :5 exp&$4 ,!n ! contraction ( ano!r set ( muscles decreases ! size ( ! ?oracic cavity1 & ! air is squeez$ out aga94 ,! action is j z truly me*anical z is t ( ! blacksmi?'s bell[s4 ,! relation ( ! air to ! blood is j z simple4 ,9 ! blood !re are v>i\s *emical +r$i5ts1 among :i* is "o kn[n z hmoglob94 ,x does n conc]n u at pres5t to ask :]e ?is mat]ial comes f1 s9ce ?is "q is "p ( ! broad] "q1 ! orig9 ( ! ma*9e1 to be discuss$ 9 ! second "p ( ?is "w4 ,! hmoglob9 is a normal con/itu5t ( ! blood1 &1 be+ r$ 9 col\r1 gives ! r$ col\r to ! blood4 ,?is hmoglob9 has peculi> relations to oxyg54 ,x c be sep>at$ f ! blood & exp]im5t$ ^u by ! *emi/ 9 8 laboratory4 ,x is f\nd t :5 hmoglob9 is br\ght 9 contact ) oxyg51 "u suffici5t pressure x w =m a *emical union ) x4 ,?is *emical union is1 h[ev]1 :at ! *emi/ calls a loose comb9ation1 s9ce x is readily brok5 up4 ,if ! oxyg5 is above a c]ta9 r l[ pressure1 ! union w take place2 :ile if ! pressure be bel[ ?is po9t ! union is at once de/roy$1 & ! oxyg5 leaves ! hmoglob9 to become free4 ,all ( ?is is a purely *emical matt]1 & c be demon/rat$ at w 9 a te/ tube 9 ! laboratory4 ,b ?is union & disassociation is j :at occurs z ! f\ndation ( respiration4 ,! blood com+ to ! lungs conta9s hmoglob91 & s9ce ! oxyg5 pressure 9 ! air is q high1 ?is hmoglob9 unites at once ) a quantity ( oxyg5 :ile ! blood is fl[+ ?r\gh ! air-vessels4 ,! blood is !n c>ri$ (f 9 ! circulation to ! active tissues l ! muscles4 ,^! tissues are con/antly us+ oxyg5 to c>ry on _! life processes1 & consequ5tly at all times use up ab\t all ! oxyg5 )9 _! rea*4 ,! result is t 9 ^! tissues ! oxyg5 pressure is v l[1 & :5 ! oxyg5-lad5 hmoglob9 rea*es !m ! association ( ! hmoglob9 ) oxyg5 is at once brok5 up & ! oxyg5 set free 9 ! tissue4 ,x passes at once to ! lymph1 f :i* ! active tissues seize x = ! purpose ( c>ry+ on ! oxidiz+ processes ( ! body4 ,?is :ole matt] ( supply+ ! body ) oxyg5 is ?us fundam5tally a *emical "o1 controll$ by *emical laws4 ,removal ( ,wa/e4--,! next /ep 9 ?is life process is "o ( difficulty4 ,aft] ! food & oxyg5 h rea*$ ! tissues x is seiz$ by ! liv+ cell4 ,! food mat]ial is n[ oxidiz$ by ! oxyg5 & its lat5t en]gy is lib]at$1 & appe>s 9 ! =m ( motion or heat or "s o!r vital function4 ,h]e9 is ! really my/]i\s "p ( ! life process2 b = ! pres5t we w ov]look ! my/]y ( ?is action1 & consid] ! results f a purely mat]ial /&po9t4 ,9 a /eam eng9e ! fundam5tal process by :i* ! lat5t en]gy ( ! fuel is lib]at$ is t ( oxidation4 ,! oxyg5 ( ! air unites ) ! *emical elem5ts ( ! fuel1 & breaks up t fuel into simple comp\nds--:i* may be *iefly consid]$ z ?ree--c>bonic dioxide 7,,co#b71 wat] 7,h#b,o71 & a%4 ,! en]gy conta9$ 9 ! orig9al comp\nd c n be held by ^! simpl] bodies1 & x !re=e escapes z heat4 ,j ! same process1 ) ( c\rse diff]5ce 9 details1 is f\nd 9 ! liv+ ma*9e4 ,! food1 aft] rea*+ ! liv+ cell1 is unit$ ) ! oxyg51 &1 s f> z *emical results are conc]n$1 ! process is mu* ! same z if x occurr$ outside ! body4 ,! food is brok5 into simpl] comp\nds & ! conta9$ en]gy is lib]at$4 ,! en]gy is1 by ! me*anism ( ! ma*9e1 *ang$ into motion or n]v\s impulse1 etc4 ,! food is brok5 into simple comp\nds1 :i* are *iefly c>bonic dioxide1 wat]1 & a%2 ! a% be+1 h[ev]1 q diff]5t f ! a% obta9$ f burn+ coal4 ,n[ ! eng9e mu/ h its *imney to remove ! gases & vap\rs 7! ,,co#b & ,h#b,o7 & its a%pit = ! a%es4 ,9 ! same way ! liv+ ma*9e has its excretory sy/em = remov+ wa/es4 ,9 ! removal ( ! c>bonic acid & wat] we h to d once m ) ! respiratory sy/em1 & ! process is simply a repetition ( ! /ory ( gas diffusion1 *emical union1 & osmosis4 ,x is suffici5t "h to say t ! process is j z simple & z easily expla9$ z ^? already describ$4 ,! elim9ation ( ^! wa/es is simply a problem ( *emi/ry & me*anics4 ,9 ! removal ( ! a%1 h[ev]1 we h some?+ m1 = "h aga9 we are br\ght up aga9/ ! vital action ( ! cell4 ,?is a% takes *iefly ! =m ( a comp\nd kn[n z urea1 :i* f9ds its way into ! g5]al circulatory sy/em4 ,f ! blood x is f9ally remov$ by ! kidneys4 ,9 ! kidneys are a l>ge numb] ( bits ( liv+ matt] 7kidney cells71 :i* h ! p[] ( seiz+ hold ( ! urea z ! blood is fl[+ ov] !m1 & aft] ?us tak+ x out ( ! blood !y deposit x 9 a s]ies ( tubes :i* lead to ! bladd] & h5ce to ! ext]ior4 ,! br++ ( ?is a% to ! kidney cell is a me*anical matt]1 bas$ simply ^u ! fl[ ( ! blood4 ,! seiz+ ( ! urea by ! kidney cell is a vital ph5om5on :i* we mu/ waive = ! mom5t4 ,up to ?is po9t 9 ! analysis !re has be5 no difficulty1 & no "o c fail to agree ) ! conclusions4 ,! position we rea* is z foll[s3 ,s f> z relates to ! g5]al problems ( en]gy 9 ! univ]se ! body is a ma*9e4 ,x nei!r creates nor de/roys en]gy1 b simply trans=ms "o =m into ano!r4 ,9 attempt+ to expla9 ! action ( ! ma*9e1 we f9d t = ! functions ?us f> consid]$ 7sometimes call$ ! vegetative functions7 ! laws ( *emi/ry & physics furni% adequate explanation4 ,we mu/ n[ look a little fur!r1 & "q "s ( ! functions ! me*anical nature ( :i* is less obvi\s4 ,! :ole op]ation ?us f> describ$ is "u ! control ( ! n]v\s sy/em1 :i* acts some:at l ! eng9e] ( an eng9e4 ,c ?is phase ( liv+ activity be includ$ )9 ! conception ( ! body z a ma*9e8 ,n]v\s ,sy/em4--,:5 we come to try to apply me*anical pr9ciples to ! n]v\s sy/em1 we meet ) :at seems at fir/ to be no ?or\ghf>e4 ,:ile deal+ ) ! gross] que/ions ( *emical comp\nds1 heat1 & motion1 !re is little difficulty 9 apply+ natural laws to ! explanation ( liv+ ph5om5a4 ,b ! problem ) ! n]v\s sy/em is v diff]5t4 ,x is only to-day t we are f9d+ t ! problem is op5 to /udy1 to say no?+ ( solution4 ,x is true t m5tal & o!r n]v\s ph5om5a h be5 /udi$ = a long "t1 b ?is /udy has be5 simply ! /udy ( ^! ph5om5a by !mselves )\t a ?\ght ( _! correlation ) o!r ph5om5a ( nature4 ,x is a matt] ( q rec5t conception t n]v\s ph5om5a h any direct relation to ! o!r realms ( nature4 ,our fir/ "q mu/ be :e!r we c f9d any correlation betwe5 n]v\s en]gy & o!r types ( en]gy4 ,= our purpose x w be conv5i5t to di/+ui% betwe5 ! ph5om5a ( simple n]v\s transmission & ! ph5om5a ( m5tal activity4 ,! =m] are ! simpl]1 & (f] ! greate/ hope ( solution4 ,if we are to f9d any correlation betwe5 n]v\s en]gy & o!r physical en]gy1 we mu/ d s by f9d+ "s way ( measur+ n]v\s en]gy & comp>+ x ) ! latt]4 ,?is has be5 v difficult1 = we h no way ( measur+ a n]v\s impulse directly4 ,9 ! l>g] exp]im5ts ^u ! income & outgo ( ! body1 9 ! respiration app>atus m5tion$ above1 n]v\s ph5om5a app>5tly leave no trace4 ,s f> z exp]im5ts h gone z yet1 !re is no evid5ce ( an exp5diture ( extra physical en]gy :5 ! n]v\s sy/em is 9 action4 ,?is is n surpris+1 h[ev]1 = ?is app>atus is entirely too co>se to measure su* delicate factors4 ,t !re is a correlation betwe5 n]v\s en]gy & physical en]gy is1 h[ev]1 pretty def9itely prov$ by exp]im5ts along diff]5t l9es4 ,! fir/ /ep 9 ?is direction 0 to f9d t a n]v\s /imulus c be measur$ at lea/ indirectly4 ,:5 ! n]ve is /imulat$ !re passes f "o end to ! o!r an impulse1 & ! rapidity ) :i* x travels c be accurately measur$4 ,:5 su* an impulse rea*es ! bra9 x may give rise to a consci\s s5sation1 & a some:at def9ite e/imation c be made ( ! am\nt ( "t requir$ = ?is4 ,! p]iods are v %ort1 ( c\rse1 b !y are n in/antane\s4 ,! n]v\s impulse1 c be /udi$ 9 /ill o!r ways4 ,we f9d t ! impulse c be />t$ by ord9>y =ms ( en]gy4 ,a me*anical %ock1 a *emical or an electrical %ock w develop n]v\s en]gy4 ,n[ ^! are ord9>y =ms ( physical en]gy1 & if1 :5 !y are appli$ to a n]ve1 !y give rise to a n]v\s /imulus1 ! inf]5ce is c]ta9ly a legitimate "o t ! n]ve is simply a bit ( ma*9]y adapt$ to ! conv]sion ( c]ta9 k9ds ( physical en]gy into n]v\s en]gy4 ,if ?is is ! case1 !n x is necess>y to reg>d n]v\s en]gy z correlat$ ) o!r =ms ( en]gy4 ,o!r facts po9t 9 ! same direction4 ,n only c ! n]v\s /imulus be develop$ by an electric %ock1 b ! /r5g? ( ! /imulus is )9 c]ta9 limits proportional to ! /r5g? ( ! %ock :i* produces x4 ,aga91 n only is x f\nd t an electrical %ock c develop a n]v\s /imulus1 b conv]sely a n]v\s /imulus develops electrical en]gy4 ,9 ord9>y n]ves1 ev5 :5 n active1 slight electric curr5ts c be detect$4 ,!y are extremely slight1 & require ! mo/ delicate in/rum5ts = _! detection4 ,n[ :5 a n]ve is /imulat$ ^! curr5ts are imm$iately affect$ 9 su* a way t "u prop] conditions !y are increas$ 9 int5sity4 ,! increase is suffici5t to make itself easily se5 by ! motion ( a galvanomet]4 ,! motion ( ! galvanomet] "u ^! conditions gives a ready means ( /udy+ ! "* ( ! n]v\s impulse4 ,by its use x c be det]m9$ t ! n]ve impulse travels along ! n]ve l a wave1 & we c approximately det]m9e ! l5g? & %ape ( ! wave & its relative height at v>i\s po9ts4 ,n[ :at is ! significance ( all ^! facts = our discussion8 ,toge!r !y po9t cle>ly to ! conclusion t n]v\s en]gy is correlat$ ) o!r =ms ( physical en]gy4 ,s9ce ! n]v\s /imulus is />t$ by o!r =ms ( en]gy1 & s9ce x c1 9 turn1 modify ord9>y =ms ( en]gy1 we c n avoid ! conclusion t ! n]v\s impulse is only a special =m ( en]gy develop$ )9 ! n]ve4 ,x is a =m ( wave motion peculi> to ! n]ve sub/ance1 b correlat$ ) & develop$ f o!r types ( en]gy4 ,?is1 ( c\rse1 makes ! n]ve simply a bit ( ma*9]y4 ,if ?is conclusion is true1 ! developm5t ( a n]ve impulse w\ld mean t a c]ta9 portion ( food is brok5 to pieces 9 ! body to lib]ate en]gy1 & ?is %\ld be accompani$ by an elim9ation ( c>bonic dioxide & heat4 ,?is is easily %[n to be true ( muscle action4 ,:5 we remove a muscle f ! body x may rema9 capable ( contract+ = "s "t4 ,by /udy+ x "u ^! conditions we f9d t x gives rise to c>bonic dioxide & o!r sub/ances1 & lib]ates heat :5ev] x contracts4 ,z already notic$1 9 ! respiration exp]im5ts1 :5ev] ! individual exp]im5t$ ^u makes any motions1 !re is an accompany+ elim9ation ( wa/e products & a developm5t ( heat4 ,b ?is does n appe> to be demon/rable = ! actions ( ! n]v\s sy/em4 ,al?\gh v c>eful exp]im5ts h be5 made1 x has z yet be5 f\nd impossible to detect any rise 9 temp]ature :5 a n]ve impulse is pass+ ?r\gh a n]ve1 nor is !re any demon/rable excretion ( wa/e products4 ,?is w\ld be a s]i\s objection to ! conception ( ! n]ve z a ma*9e 7 x n = ! fact t ! n]ve is s small t ! total sum ( its n]v\s en]gy mu/ be v slight4 ,! total en]gy ( ?is m9ute ma*9e is s slight t x c n be detect$ by our comp>atively r\gh in/rum5ts ( measurem5t4 ,9 %ort1 all evid5ce goes to %[ t ! n]ve impulse is a =m ( motion1 & h5ce ( en]gy1 correlat$ ) o!r =ms ( physical en]gy4 ,! n]ve is1 h[ev]1 a v delicate ma*9e1 & its total am\nt ( en]gy is v small4 ,a t9y wat* is a m delicate ma*9e ?an a wat]-:eel1 & its actions are m dep5d5t ^u ! accuracy ( its adju/m5t4 ,! wat]-:eel may be made v co>se & yet be p]fectly efficaci\s1 :ile ! wat* mu/ be fa%ion$ ) extreme delicacy4 ,yet ! wat]-:eel trans=ms va/ly m en]gy ?an ! wat*4 ,x may drive ! _m ma*9es 9 a factory1 :ile ! wat* c d no m ?an move itself4 ,b :o c d\bt t ! wat*1 z well z ! wat]-:eel1 is gov]n$ by ! law ( ! correlation ( =ces8 ,s ! n]v\s sy/em ( ! liv+ ma*9e is delicately adju/$ & easily put out ( ord]1 & its action involves only a small am\nt ( en]gy2 b x is j z truly subject to ! law ( ! cons]vation ( en]gy z is ! m massive muscle4 ,s5sations4--,pursu+ ?is subject fur!r1 we next notice t x is possible to trace a connection betwe5 physical en]gy & s5sations4 ,s5sations are excit$ by c]ta9 ext]nal =ms ( motion4 ,! liv+ ma*9e has1 = example1 "o piece ( app>atus capable ( be+ affect$ by rapidly vibrat+ waves ( air4 ,?is bit ( ! ma*9e we call ! e>4 ,x is made ( p>ts delicately adju/$1 s t vibrat+ waves ( air set !m 9 motion1 & _! motion />ts a n]v\s /imulus travell+ along ! auditory n]ve4 ,z a result ?is app>atus w be set 9 motion1 & an impulse s5t along ! auditory n]ve :5ev] t ext]nal type ( motion :i* we call s\nd /rikes ! e>4 ,9 o!r words1 ! e> is a piece ( app>atus = *ang+ air vibrations into n]v\s /imulation1 & is !re=e a ma*9e4 ,app>5tly ! mat]ial 9 ! e> is l a bit ( gunp[d]1 capable ( be+ explod$ by c]ta9 k9ds ( ext]nal excitation2 b nei!r ! gunp[d] nor ! mat]ial 9 ! e> develops any en]gy o!r ?an t 9 x at ! outset4 ,9 ! same way ! optic n]ve has1 at its end1 a bit ( me*anism readily excit$ by light vibrations ( ! e!r1 & h5ce ! optic n]ve w always be excit$ :5 e!r vibrations *ance to h an opportunity ( sett+ ! optic ma*9]y 9 motion4 ,& s on ) ! o!r s5ses4 ,ea* s5sory n]ve has1 at its end1 a bit ( ma*9]y design$ = ! trans=mation ( c]ta9 k9ds ( ext]nal en]gy into n]v\s en]gy1 j z a dynamo is a ma*9e = trans=m+ motion into electricity4 ,if ! ma*9e is brok51 ! ext]nal =ce has no long] any p[] ( act+ ^u x1 & ! individual becomes deaf or bl9d4 ,m5tal ,ph5om5a4--,?us f> 9 our analysis we ne$ n hesitate 9 recogniz+ a correlation betwe5 physical & n]v\s en]gy4 ,ev5 ?\gh n]v\s en]gy is v subtle & only affects our in/rum5ts ( measurem5ts "u exceptional conditions1 ! fact t n]v\s =ces are excit$ by physical =ces1 & are !mselves directly measurable1 indicates t !y are correlat$ ) physical =ces4 ,up to ?is po9t1 !n1 we may confid5tly say t ! n]v\s sy/em is "p ( ! ma*9e4 ,b :5 we turn to ! m obscure p>ts ( ! n]v\s ph5om5a1 ^? :i* we commonly call m5tal1 we f9d ourselves oblig$ to /op abruptly4 ,we may trace ! ext]nal =ce to ! s5sory organ1 we may trace ?is =ce into a n]v\s /imulus1 & may foll[ ?is /imulus to ! bra9 z a wave motion1 & !re=e z a =m ( physical en]gy4 ,b !re we mu/ /op4 ,we h no idea ( h[ ! n]v\s impulse is conv]t$ into a s5sation4 ,! m5tal side ( ! s5sation appe>s to /& 9 a category by itself1 & we c n look ^u x z a =m ( en]gy4 ,x is true t _m brave attempts h be5 made to associate ! two4 ,s5sations c be measur$ z to int5sity1 & ! int5sity ( a s5sation is to a c]ta9 ext5t dep5d5t ^u ! int5sity ( ! /imulus excit+ x4 ,! m5tal s5sation is und\bt$ly excit$ by ! physical wave ( n]v\s impulse4 ,9 ! gr[? ( ! individual ! developm5t ( its m5tal p[]s are f\nd to be p>allel to ! developm5t ( its n]ves & bra9--a fact :i*1 ( c\rse1 proves t m5tal p[] is dep5d5t ^u bra9 /ructure4 ,fur!r1 x is f\nd t c]ta9 visible *anges occur 9 c]ta9 p>ts ( ! bra9--! bra9 cells--:5 !y are excit$ into m5tal activity4 ,su* s]ies ( facts po9t to an association betwe5 ! m5tal side ( s5sations & physical /ructure ( ! ma*9e4 ,b !y d n prove any correlation betwe5 !m4 ,! unlik5ess ( m5tal & physical ph5om5a is s absolute t we mu/ hesitate ab\t draw+ any connection betwe5 !m4 ,x is impossible to conceive ! m5tal side ( a s5sation z a =m ( wave motion4 ,if1 fur!r1 we take into consid]ation ! o!r ph5om5a associat$ ) ! n]v\s sy/em1 ! m di/9ctly m5tal processes1 we h absolutely no data = any comp>ison4 ,we c n imag9e ?\ght measur$ by units1 & until we c conceive ( su* measurem5t we c get no mean+ f any attempt to f9d a correlation betwe5 m5tal & physical ph5om5a4 ,x is true t c]ta9 psy*ologi/s h tri$ to build up a conception ( ! physical nature ( m9d2 b _! attempts h *iefly result$ 9 build+ up a conception ( ! physical nature ( ! bra91 & !n ignor+ ! radical *asm t exi/s betwe5 m9d & matt]4 ,! possibility ( describ+ a complex bra9 z gr[+ p>allel to ! gr[? ( a complex m9d has be5 reg>d$ z equival5t to prov+ _! id5tity4 ,all attempts 9 ?is direction ?us f> h simply ignor$ ! fact t ! /imulation ( a n]ve1 a purely physical process1 is n ! same ?+ z a m5tal action4 ,:at ! future may disclose x is haz>d\s to say1 b at pres5t ! m5tal side ( ! liv+ ma*9e has n be5 includ$ )9 ! conception ( ! me*anical nature ( ! organism4 ,! ,liv+ ,body is a ,ma*9e4--,review+ ! subject up to ?is po9t1 :at mu/ be our v]dict z to our ability to und]/& ! runn+ ( ! liv+ ma*9e8 ,9 ! fir/ place1 we are ju/ifi$ 9 reg>d+ ! body z a ma*9e1 s9ce1 s f> z conc]ns its relations to en]gy1 x is simply a piece ( me*anism--complicat$1 inde$1 beyond any o!r ma*9e1 b /ill a ma*9e = *ang+ "o k9d ( en]gy into ano!r4 ,x receives ! en]gy 9 ! =m ( *emical composition & conv]ts x into heat1 motion1 n]v\s wave motion1 etc4 ,all ( ?is is sure en\gh4 ,:e!r o!r =ms ( n]v\s & m5tal activity c be plac$ "u ! same category1 or :e!r ^! mu/ be reg>d$ z belong+ to a realm by !mselves & outside ( ! scope ( en]gy 9 ! physical s5se1 c n p]haps be yet def9itely decid$4 ,we c simply say t z yet no "o has be5 able ev5 to conceive h[ ?\ght c be comm5surate ) physical en]gy4 ,! utt] unlik5ess ( ?\ght & wave motion ( any k9d leads u at pres5t to feel t on ! side ( m5tality ! comp>ison ( ! body ) a ma*9e fails ( be+ complete4 ,9 reg>d to ! second half ( ! "q1 :e!r natural =ces are adequate to expla9 ! runn+ ( ! ma*9e1 we h aga9 be5 able to rea* a satisfactory positive answ]4 ,dige/ion1 assimilation1 circulation1 respiration1 excretion1 ! pr9cipal categories ( physiological action1 & at lea/ c]ta9 phases ( ! action ( ! n]v\s sy/em are readily und]/ood z controll$ by ! action ( *emical & physical =ces4 ,9 ! accompli%m5t ( ^! actions !re is no ne$ = ! supposition ( any =ce o!r ?an ^? :i* are at our comm& 9 ! sci5tific laboratory4 ,! ,liv+ ,ma*9e ,con/ructive z well z ,de/ructive4--,9 "o respect ! liv+ ma*9e diff]s f all o!rs4 ,! action ( all o!r ma*9es results 9 ! de/ruction ( organiz$ mat]ial1 & ?us 9 a degradation ( matt]4 ,= example1 a /eam eng9e receives coal1 a sub/ance ( high *emical composition1 & breaks x into m simple comp\nds1 9 ?is way lib]at+ its /or$ en]gy4 ,n[ if we exam9e all =ms ( artificial ma*9es1 we f9d 9 ! same way t !re is always a de/ruction ( comp\nds ( high *emical composition4 ,9 su* ma*9es x is common to />t ) heat z a s\rce ( en]gy1 & ?is heat is always produc$ by ! break+ ( *emical comp\nds to pieces4 ,9 all *emical processes go+ on 9 ! *emi/'s laboratory !re is simil>ly a de/ruction ( organic comp\nds4 ,x is true t ! *emi/ sometimes makes complex comp\nds out ( simpl] ones2 b 9 ord] to d ?is he is oblig$ to use heat to br+ ab\t ! comb9ation1 & ?is heat is obta9$ f ! de/ruction ( a mu* l>g] quantity ( high comp\nds ?an he manufactures4 ,! total result is !re=e de/ruction r ?an manufacture ( high comp\nds4 ,?us x is a fact1 t 9 all artificial ma*9es & 9 all artificial *emical processes !re is1 z a total result1 a degradation ( matt] t[>d ! simpl] f ! m complex comp\nds4 ,z a result ( ! action ( ! liv+ ma*9e1 h[ev]1 we h ! opposite process ( con/ruction go+ on4 ,all high *emical comp\nds are to be trac$ to liv+ be+s z _! s\rce4 ,:5 gre5 plants gr[ 9 sunlight !y take simple comp\nds & comb9e !m toge!r to =m m complex ones 9 su* a way t ! total result is an increase ( *emical comp\nds ( high complexity4 ,9 do+ ?is !y use ! en]gy ( sunlight1 :i* !y !n /ore away 9 ! comp\nds =m$4 ,!y ?us produce />*es1 oils1 proteids1 woods1 etc41 & ^! /ores ( en]gy n[ may be us$ by artificial ma*9es4 ,! liv+ ma*9e builds up1 o!r ma*9es pull d[n4 ,! liv+ ma*9e /ores sunlight 9 complex comp\nds1 o!r ma*9es take x out & use x4 ,! liv+ organism is !re=e to be comp>$ to a sun eng9e1 :i* obta9s its en]gy directly f ! sun1 r ?an to ! ord9>y eng9e4 ,:ile ?is does n 9 ! slighte/ militate aga9/ ! idea ( ! liv+ body z a ma*9e1 x does indicate t x is a ma*9e ( q a diff]5t "* f any o!r1 & has p[]s possess$ by no o!r ma*9e4 ,liv+ ma*9es alone increase ! am\nt ( *emical comp\nds ( high complexity4 ,we mu/ notice1 h[ev]1 t ?is p[] ( con/ruction 9 di/9ction f de/ruction1 is possess$ only by "o special class ( liv+ ma*9es4 ,gre5 plants alone c ?us increase ! /ore ( organic comp\nds 9 ! _w4 ,all col\rless plants & all animals1 on ! o!r h&1 live by de/roy+ ^! comp\nds & us+ ! en]gy ?us lib]at$2 9 ?is respect be+ m l ord9>y artificial ma*9es4 ,! animal does inde$ p]=m c]ta9 con/ructive op]ations1 manufactur+ complex mat]ial out ( simpl] bodies2 z1 = example1 mak+ fats out ( />*es4 ,b 9 ?is op]ation x de/roys a l>ge am\nt ( organic mat]ial to furni% ! en]gy = ! con/ruction1 s t ! total result is a degradation ( *emical comp\nds r ?an a con/ruction4 ,con/ructive processes1 :i* increase ! am\nt ( high comp\nds 9 nature1 are conf9$ to ! liv+ ma*9e1 & inde$ to "o special =m ( x1 viz41 ! gre5 plant4 ,?is con/ructive p[] radically sep>ates ! liv+ f o!r ma*9es2 = :ile con/ructive processes are possible to ! *emi/1 & :ile eng9es mak+ use ( sunlight are possible1 ! liv+ ma*9e is ! only ma*9e t increases ! am\nt ( high *emical comp\nds 9 ! _w4 ,! ,vital ,factor4--,) all ?is explanation ( life processes x c n fail to be app>5t t we h n really rea*$ ! c5tre ( ! problem4 ,we h expla9$ _m second>y processes1 b ! prim>y ones are /ill unsolv$4 ,9 /udy+ dige/ion we rea* an und]/&+ ( ev]y?+ until we come to ! active vital prop]ty ( ! gl&-cells 9 secret+4 ,9 /udy+ absorption we und]/& ! process until we come to :at we h call$ ! vital p[]s ( ! absorptive cells ( ! alim5t>y canal4 ,! circulation is intelligible until we come to ! beat+ ( ! he>t & ! contraction ( ! muscles ( ! blood-vessels4 ,excretion is also p>tly expla9$1 b "h aga9 we f9ally mu/ ref] c]ta9 processes to ! vital p[]s ( active cells4 ,& ?us :]ev] we probe ! problem we f9d ourselves able to expla9 _m second>y problems1 :ile ! fundam5tal ones we /ill attribute to ! vital prop]ties ( ! active tissues4 ,:y a muscle contracts or a gl& secretes we h c]ta9ly n yet answ]$4 ,! relation ( ! actions to ! g5]al problems ( correlation ( =ce is simple en\gh4 ,t a muscle is a ma*9e 9 ! s5se ( our def9ition is beyond "q4 ,b ! problem ( :y a muscle acts is n answ]$ by %[+ t x d]ives its en]gy f brok5 food mat]ial4 ,!re are pla9ly /ill left = u a numb] ( fundam5tal problems1 al?\gh ! second>y ones are soluble4 ,:at c we say 9 reg>d to ^! fundam5tal vital p[]s ( ! active tissues8 ,fir/ly1 we mu/ notice t _m ( ! processes :i* we n[ und]/& 7 =m]ly class$ z vital1 & we only reta9 "u ?is t]m ^? :i* are n yet expla9$4 ,?is1 ( c\rse1 sugge/s to u t p]haps we may "s day f9d an explanation = all ! s-call$ vital p[]s by ! application ( simple physical =ces4 ,is x a fact t ! only significance to ! t]m vital is t we h n yet be5 able to expla9 ^! processes to our entire satisfaction8 ,is ! diff]5ce betwe5 :at we h call$ ! second>y processes & ! prim>y ones only "o ( degree8 ,is !re a probability t ! actions :i* we n[ call vital w "s day be z readily und]/ood z ^? :i* h already be5 expla9$8 ,is !re any me?od by :i* we c approa* ^! fundam5tal problems ( muscle action1 he>t beat1 gl& secretion1 etc48 ,evid5tly1 if ?is is to be done1 x mu/ be by resolv+ ! body into its simple units & /udy+ ^! units4 ,our /udy ?us f> has be5 a /udy ( ! ma*9]y ( ! body z a :ole2 b we h f\nd t ! v>i\s p>ts ( ! ma*9e are !mselves active1 t ap>t f ! action ( ! g5]al ma*9e z a :ole1 ! sep>ate p>ts h vital p[]s4 ,we mu/1 !re=e1 get rid ( ?is complicat$ ma*9]y1 :i* confuses ! problem1 & see if we c f9d ! fundam5tal units :i* %[ ^! prop]ties1 un5cumb]$ by ! second>y ma*9]y :i* has hi!rto attract$ our att5tion4 ,we mu/ turn n[ to ! problem connect$ ) protoplasm & ! liv+ cell1 s9ce "h1 if any:]e1 c we f9d ! life sub/ance r$uc$ to its l[e/ t]ms4 ,,*apt] ,,ii4 ,,! ,,cell ,,& ,,protoplasm4 ,vital ,prop]ties4--,we h se5 t ! g5]al activities ( ! body are intelligible accord+ to *emical & me*anical laws1 provid$ we c assume z _! f\ndation ! simple vital prop]ties ( liv+ ph5om5a4 ,we mu/ n[ approa* clos] to ! c5tre ( ! problem1 & ask :e!r we c trace ^! fundam5tal prop]ties to _! s\rce & f9d an explanation ( !m4 ,9 ! fir/ place1 :at are ^! prop]ties8 ,! vital p[]s are v>i$1 & lie at ! basis ( e =m ( liv+ activity4 ,:5 we free !m f complications1 h[ev]1 !y may all be r$uc$ to f\r4 ,^! are3 7#a7 ,irritability1 or ! prop]ty possess$ by liv+ matt] ( react+ :5 /imulat$4 7#b7 ,movem5t1 or ! p[] ( contract+ :5 /imulat$4 7#c7 ,metabolism1 or ! p[] ( absorb+ extrane\s food & produc+ 9 x c]ta9 *emical *anges1 :i* ei!r conv]t x into m liv+ tissue or break x to pieces to lib]ate ! inclos$ en]gy4 7#d7 ,reproduction1 or ! p[] ( produc+ new individuals4 ,f ^! f\r simple vital activities all o!r vital actions foll[2 & if we c f9d an explanation ( ^!1 we h expla9$ ! liv+ ma*9e4 ,if we grant t c]ta9 p>ts ( ! body c assimilate food & multiply1 hav+ ! p[] ( contraction :5 irritat$1 we c readily expla9 ! o!r functions ( ! liv+ ma*9e by ! application ( ^! prop]ties to ! complicat$ ma*9]y ( ! body4 ,b ^! prop]ties are fundam5tal1 & unless we c grasp !m we h fail$ to rea* ! c5tre ( ! problem4 ,z we pass f ! m to ! less complicat$ animals we f9d a gradual simplification ( ! ma*9]y until ! ma*9]y app>5tly disappe>s4 ,) ?is simplification ( ! ma*9]y we f9d ! animals provid$ ) less v>i$ p[]s & ) less delicate adaptations to conditions4 ,b )al we f9d ! fundam5tal p[]s ( ! liv+ organisms ! same4 ,= ! p]=mance ( ^! fundam5tal activities !re is app>5tly ne$$ no ma*9]y4 ,! simple types ( liv+ bodies are simple 9 numb] ( p>ts1 b !y possess ess5tially ! same p[]s ( assimilation & gr[? t *>act]ize ! high] =ms4 ,x is evid5t t 9 our attempt to trace ! vital prop]ties to _! s\rce we may proce$ 9 two ways4 ,we may ei!r direct our att5tion to ! simple/ organisms :]e all second>y ma*9]y is want+1 or to ! smalle/ p>ts into :i* ! tissues ( high] organisms c be resolv$ & yet reta9 _! life prop]ties4 ,9 ei!r way we may hope to f9d liv+ ph5om5a 9 its simple/ =m indep5d5t ( second>y ma*9]y4 ,b ! fact is1 :5 we turn our att5tion 9 ^! two directions1 we f9d ! result is ! same4 ,if we look = ! l[e/ organisms we f9d !m among =ms t are made ( a s+le cell1 & if we analyze ! tissues ( high] animals we f9d ! ultimate p>ts to be cells4 ,?us1 9 ei!r direction1 ! /udy ( ! cell is =c$ ^u u4 ,be=e beg9n+ ! /udy ( ! cell x w be well = u to try to get a cle> notion ( ! exact nature ( ! problems we are try+ to solve4 ,we wi% to expla9 ! activities ( life ph5om5a 9 su* a way z to make !m intelligible ?r\gh ! application ( natural =ces4 ,t ^! processes are fundam5tally *emical ones is evid5t en\gh4 ,a *emical oxidation ( food lies at ! basis ( all vital activity1 & x is ?us ?r\gh ! action ( *emical =ces t ! vital p[]s are furni%$ ) _! en]gy4 ,b ! real problem is :at x is 9 ! liv+ ma*9e t controls ^! *emical processes4 ,fat & />* may be oxidiz$ 9 a *emi/'s te/ tubes1 & w !re lib]ate en]gy2 b !y d n1 "u ^! conditions1 manife/ vital ph5om5a4 ,proteid may be br\ght 9 contact ) oxyg5 )\t any oxidation occurr+1 & ev5 if x is oxidiz$ no motion or assimilation or reproduction occurs "u ord9>y conditions4 ,^! ph5om5a occur only :5 ! oxidation takes place 9 ! liv+ ma*9e4 ,our problem is !n to det]m9e1 if possible1 :at x is 9 ! liv+ ma*9e t regulates ! oxidations & o!r *anges 9 su* a way z to produce f !m vital activities4 ,:y is x t ! oxidation ( />* 9 ! liv+ ma*9e gives rise to motion1 gr[?1 & reproduction1 :ile if ! oxidation occurs 9 ! *emi/'s laboratory1 or ev5 9 a bit ( dead protoplasm1 x simply gives rise to heat8 ,"o ( ! prim>y que/ions to dem& att5tion 9 ?is se>* is :e!r we are to f9d ! explanation1 at ! bottom1 a *emical or a me*anical "o4 ,9 ! simple/ =m ( life 9 :i* vital manife/ations are f\nd are we to attribute ^! prop]ties simply to *emical =ces ( ! liv+ sub/ance1 or mu/ we "h too attribute !m to ! action ( a complicat$ ma*9]y8 ,?is "q is m ?an a =mal "o4 ,t x is "o ( mo/ pr(\nd significance w appe> f ! foll[+ consid]ations3 ,*emical aff9ity is a well recogniz$ =ce4 ,"u ! action ( ?is =ce *emical comp\nds are produc$ & diff]5t comp\nds =m$ "u diff]5t conditions4 ,! prop]ties ( ! diff]5t comp\nds diff] ) _! composition1 & ! m complex are ! comp\nds ! m v>i$ _! prop]ties4 ,n[ x might be assum$ z an hypo!sis t !re c\ld be a *emical comp\nd s complex z to possess1 among o!r prop]ties1 t ( caus+ ! oxidation ( food to occur 9 su* a way z to produce assimilation & gr[?4 ,su* a comp\nd w\ld1 ( c\rse1 be alive1 & x w\ld be j z true t its p[] ( assimilat+ food w\ld be "o ( its physical prop]ties z x is t freez+ is a physical prop]ty ( wat]4 ,if su* an hypo!sis %\ld prove to be ! true "o1 !n ! problem ( expla9+ life w\ld be a *emical "o1 = all vital prop]ties w\ld be r$ucible to ! prop]ties ( a *emical comp\nd4 ,x w\ld !n only be necess>y to %[ h[ su* a comp\nd came into exi/5ce & we %\ld h expla9$ life4 ,nor w\ld ?is be a hopeless task4 ,we are well acqua9t$ ) =ces adequate to ! =mation ( *emical comp\nds4 ,if ! =ce ( *emical aff9ity is adequate "u c]ta9 conditions to =m "s comp\nds1 x is easy to conceive x z a possibility "u o!r conditions to produce ?is *emical liv+ sub/ance4 ,our se>* w\ld ne$ !n to be = a set ( conditions "u :i* our liv+ comp\nd c\ld h be5 produc$ by ! kn[n =ces ( *emical aff9ity4 ,b suppose1 on ! o!r h&1 t we f9d ?is simple/ bit ( liv+ matt] is n a *emical comp\nd1 b is 9 itself a complicat$ ma*9e4 ,suppose t1 aft] r$uc+ ?is vital sub/ance to its simple/ type1 we f9d t ! sub/ance ) :i* we are deal+ n only has complex *emical /ructure1 b t x also possesses a l>ge numb] ( /ructural p>ts adapt$ to ea* o!r 9 su* a way z to "w toge!r 9 ! =m ( an intricate me*anism4 ,! :ole problem w\ld !n be *ang$4 ,to expla9 su* a ma*9e we c\ld no long] call ^u *emical =ces4 ,*emical aff9ity is adequate to ! explanation ( *emical comp\nds h[ev] complicat$1 b x _c (f] any explanation = ! adaptation ( p>ts :i* make a ma*9e4 ,! problem ( ! orig9 ( ! simple/ =m ( life w\ld !n be no long] "o ( *emical b "o ( me*anical evolution4 ,x is pla9 !n t ! "q ( :e!r we c attribute ! prop]ties ( ! simple/ type ( life to *emical composition or to me*anical /ructure is m ?an a =mal "o4 ,! ,discov]y ( ,cells4--,x is difficult = u to-day to h any adequate idea ( ! wond]ful flood ( light t 0 ?r[n ^u sci5tific & philosophical /udy by ! discov]ies :i* are gr\p$ ar\nd ! t]ms cells & protoplasm4 ,cells & protoplasm h become s ?or\ghly a "p ( mod]n biology t we c h>dly picture to ourselves ! vagu5ess ( k be=e ^! facts 7 recogniz$4 ,p]haps a some:at crude comp>ison w illu/rate ! relation :i* ! discov]y ( cells _h to ! /udy ( life4 ,imag9e = a mom5t1 "s intellig5t be+ locat$ on ! moon & try+ to /udy ! ph5om5a on ! e>?'s surface4 ,suppose t he is provid$ ) a telescope suffici5tly p[]ful to disclose mod]ately l>ge objects on ! e>?1 b n small] ones4 ,he w\ld see cities 9 v>i\s p>ts ( ! _w ) wide diff]5ces 9 appe>ance1 size1 & %ape4 ,he w\ld see railroad tra9s on ! e>? ru%+ to & fro4 ,he w\ld see new cities aris+ & old ones increas+ 9 size1 & we may imag9e him speculat+ z to _! me?od ( orig9 & ! reasons :y !y adopt ?is or t %ape4 ,b 9 spite ( 8 mo/ acute obs]vations & 8 mo/ +5i\s speculation1 he c\ld nev] und]/& ! real significance ( ! cities1 s9ce he is n acqua9t$ ) ! actual liv+ unit4 ,imag9e n[1 if y w1 t ?is supramundane obs]v] inv5ts a telescope :i* enables him to p]ceive m m9ute objects & ?us discov]s human be+s4 ,:at a complete revolution ?is w\ld make 9 8 k ( mundane affairs6 ,we c imag9e h[ rapidly discov]y w\ld foll[ discov]y2 h[ x w\ld be f\nd t x 0 ! human be+s t build ! h\ses1 con/ruct & run ! railroads1 & control ! gr[? ( ! cities accord+ to _! fancy2 &1 la/ly1 h[ x w\ld be le>n$ t x is ! human be+ alone t gr[s & multiplies & t all else is ! result ( 8 activities4 ,su* a supramundane obs]v] w\ld f9d himself ent]+ into a new era1 9 :i* all 8 previ\s k w\ld s9k into oblivion4 ,some?+ ( ?is same sort ( revolution 0 inaugurat$ 9 ! /udy ( liv+ ?+s by ! discov]y ( cells & protoplasms4 ,animals & plants _h be5 /udi$ = c5turies & _m accurate & pa9/ak+ obs]vations _h be5 made ^u !m4 ,monum5tal masses ( evid5ce _h be5 collect$ be>+ ^u _! %apes1 sizes1 di/ribution1 & relations4 ,anatomy _h long occupi$ ! att5tion ( naturali/s1 & ! g5]al /ructure ( animals & plants 0 already well kn[n4 ,b ! discov]ies />t+ 9 ! f\r? decade ( ! c5tury by disclos+ ! unity ( activity *ang$ ! aspect ( biological sci5ce4 ,! ,cell ,doctr9e4--,! cell doctr9e is1 9 brief1 ! !ory t ! bodies ( animals & plants are built up entirely ( m9ute elem5t>y units1 m or less indep5d5t ( ea* o!r1 & all capable ( gr[? & multiplication4 ,?is doctr9e is commonly reg>d$ z be+ inaugurat$ 9 #ahci by ,s*wann4 ,long be=e ?is1 h[ev]1 _m microscopi/s _h se5 t ! bodies ( plants are made up ( elem5t>y units4 ,9 describ+ ! b>k ( a tree 9 #affe1 ,rob]t ,hooke _h /at$ t x 0 compos$ ( little boxes or cells1 & reg>d$ x z a sort ( honeycomb /ructure ) its cells fill$ ) air4 ,! t]m cell q aptly describes ! comp>tm5ts ( su* a /ructure1 z c be se5 by a glance at ,fig4 #g1 & ?is t]m has be5 reta9$ ev5 till to-day 9 spite ( ! fact t its orig9al significance has entirely disappe>$4 ,dur+ ! la/ c5tury n a few naturali/s obs]v$ & describ$ ^! little vesicles1 always reg>d+ !m z little spaces & nev] look+ ^u !m z hav+ any significance 9 ! activities ( plants4 ,9 "o or two in/ances simil> bodies 7 notic$ 9 animals1 al?\gh no connection 0 drawn betwe5 !m & ! cells ( plants4 ,9 ! e>ly "p ( ! c5tury obs]vations ^u v>i\s k9ds ( animals & plant tissues multipli$1 & _m microscopi/s indep5d5tly ann\nc$ ! discov]y ( simil> small corpuscul> bodies4 ,f9ally1 9 #ahci1 ^! obs]vations 7 comb9$ toge!r by ,s*wann into "o g5]al !ory4 ,accord+ to ! cell doctr9e !n =mulat$1 ! p>ts ( all animals & plants are ei!r compos$ ( cells or ( mat]ial d]iv$ f cells4 ,! b>k1 ! wood1 ! roots1 ! leaves ( plants are all compos$ ( little vesicles simil> to ^? already describ$ "u ! "n ( cells4 ,9 animals ! cellul> /ructure is n s easy to make out2 b "h too ! muscle1 ! bone1 ! n]ve1 ! gl& are all made up ( simil> vesicles or ( mat]ial made f !m4 ,! cells are ( wond]fully diff]5t %apes & widely diff]5t sizes1 b 9 g5]al /ructure !y are alike4 ,^! cells1 ?us f\nd 9 animals & plants alike1 =m$ ! fir/ connect+ l9k betwe5 animals & plants4 ,?is discov]y 0 l t ( our suppos$ supramundane obs]v] :5 he fir/ f\nd ! human be+ t br\ght into connection ! widely diff]5t cities 9 ! v>i\s p>ts ( ! _w4 ,illu/ration3 ,,fig4 #g4--;,a bit ( b>k %[+ cellul> /ructure4 ,s*wann & 8 imm$iate foll[]s1 :ile recogniz+ t ! bodies ( animals & plants 7 compos$ ( cells1 7 at a loss to expla9 h[ ^! cells arose4 ,! belief held at fir/ 0 t !re exi/$ 9 ! bodies ( animals & plants a /ructureless sub/ance :i* =m$ ! basis out ( :i* ! cells develop1 9 some:at ! same way t cry/als arise f a "m liquid4 ,?is suppos$ sub/ance ,s*wann call$ ! cytobla/ema1 & he ?\ght x exi/$ betwe5 ! cells or sometimes )9 !m4 ,= example1 ! fluid "p ( ! blood is ! cytobla/ema1 ! blood corpuscles be+ ! cells4 ,f ?is /ructureless fluid ! cells 7 suppos$ to arise by a process ak9 to cry/allization4 ,to be sure1 ! cells gr[ 9 a mann] v diff]5t f t ( a cry/al4 ,a cry/al always gr[s by lay]s be+ add$ ^u its outside1 :ile ! cells gr[ by additions )9 its body4 ,b ?is 0 a m9or detail1 ! ess5tial po9t be+ t f a /ructureless liquid conta9+ prop] mat]ials ! organiz$ cell sep>at$ itself4 ,?is idea ( ! cytobla/ema 0 e>ly ?r[n into suspicion1 & almo/ at ! "t ( ! ann\ncem5t ( ! cell doctr9e c]ta9 microscopi/s made ! claim t ^! cells did n come f any /ructureless m$ium1 b by division f o!r cells l !mselves4 ,?is claim1 & its demon/ration1 0 ( ev5 great] importance ?an ! discov]y ( ! cells4 ,= a numb] ( ye>s1 h[ev]1 ! matt] 0 9 dispute1 evid5ce be+ collect$ :i* ab\t equally atte/$ ea* view4 ,x 0 a ,scot*man1 ,dr4 ,b>ry1 :o f9ally produc$ evid5ce :i* settl$ ! "q f ! /udy ( ! develop+ egg4 ,! ess5ce ( 8 discov]y 0 z foll[s3 ,! ovum ( an animal is a s+le cell1 & :5 x beg9s to develop into an embryo x fir/ simply divides into two halves1 produc+ two cells 7,fig1 #h1 a & b74 ,ea* ( ^! 9 turn divides1 giv+ f\r1 & by repeat$ divisions ( ?is k9d !re arises a solid mass ( small] cells 7,fig4 #h1 b to f17 call$ ! mulb]ry /age1 f its resemblance to a b]ry4 ,?is is1 ( c\rse1 simply a mass ( cells1 ea* d]iv$ by division f ! orig9al4 ,z ! cells increase 9 numb]1 ! mass also increases 9 size by ! absorption ( nutrim5t1 & ! cells cont9ue divid+ until ! mass conta9s ?\s&s ( cells4 ,meantime ! body ( ! animal is =m$ out ( ^! cells1 & :5 x is adult x consi/s ( millions ( cells1 all ( :i* h be5 d]iv$ by division f ! orig9al cell4 ,9 su* a hi/ory ea* cell comes f pre-exi/+ cells & a cytobla/ema plays no "p4 ,illu/ration3 ,,fig4 #h4--,successive /ages 9 ! division ( ! develop+ egg4 ,x 0 impossible1 h[ev]1 = ,b>ry or any o!r p]son to foll[ ! successive divisions ( ! egg cell ?r\gh all ! /ages to ! adult4 ,! divisions c be foll[$ = a %ort "t "u ! microscope1 b ! re/ mu/ be a matt] ( simple inf]5ce4 ,x 0 argu$ t s9ce cell orig9 beg9s 9 ?is way by simple division1 & s9ce ! same process c be obs]v$ 9 ! adult1 x is reasonable to assume t ! same process has cont9u$ un9t]rupt$ly1 & t ?is is ! only me?od ( cell orig94 ,b a f9al demon/ration ( ?is conclusion 0 n =?com+ = a long "t4 ,= _m ye>s "s biologi/s cont9u$ to believe t cells c h o!r orig9 ?an f pre-exi/+ cells4 ,ye> by ye> has ! evid5ce = su* free cell orig9 become less1 until ! view has be5 entirely ab&on$1 & to-day x is ev]y:]e admitt$ t new cells always arise f old ones by direct desc5t1 & ?us e cell 9 ! body ( an animal or plant is a direct desc5dant by division f ! orig9al egg cell4 ,! ,cell4--,b :at is ?is cell :i* =ms ! unit ( life1 & to :i* all ! fundam5tal vital prop]ties c be trac$8 ,we w fir/ glance at ! /ructure ( ! cell z x 0 und]/ood by ! e>li] microscopi/s4 ,a typical cell is %[n 9 ,fig4 #i4 ,x w be se5 t x consi/s ( ?ree q di/9ct p>ts4 ,!re is fir/ ! cell wall 7cw7 :i* is a limit+ membrane ( v>y+ ?ickness & %ape4 ,?is is 9 reality lifeless mat]ial1 & is secret$ by ! re/ ( ! cell4 ,be+ ?us produc$ by ! o!r active p>ts ( ! cell1 we w speak ( x z =m$ mat]ial 9 di/9ction f ! re/1 :i* is active mat]ial4 ,inside ?is vesicle is conta9$ a some:at transp>5t semifluid mat]ial :i* has receiv$ v>i\s names1 b :i* = ! pres5t we w call cell sub/ance 7,fig4 #i1 pr74 ,x may be abundant or scanty1 & has a widely v>y+ consi/5cy f a v liquid mass to a decid$ly ?ick jellylike sub/ance4 ,ly+ )9 ! cell sub/ance is a small body1 usually m or less sph]ical 9 %ape1 :i* is call$ ! nucleus 7,fig4 #i1 n74 ,x appe>s to ! microscope simil> to ! cell sub/ance 9 "*1 & has frequ5tly be5 describ$ z a bit ( ! cell sub/ance m d5se ?an ! rema9d]4 ,ly+ )9 ! nucleus !re are usually to be se5 "o or m small] r\nd$ bodies :i* h be5 call$ nucleoli4 ,f ! v e>lie/ p]iod t cells h be5 /udi$1 ^! ?ree p>ts1 cell wall1 cell sub/ance1 & nucleus h be5 recogniz$1 b z to _! relations to ea* o!r & to ! g5]al activities ( ! cell !re has be5 ! wide/ v>iety ( op9ion4 ,illu/ration3 ,,fig4 #i4--;,a cell2 cw is ! cell wall2 pr1 ! cell sub/ance2 n1 ! nucleus4 ,cellul> ,/ructure ( ,organisms4--,x w be well to notice next j :at is meant by say+ t all liv+ bodies are compos$ ( cells4 ,?is c be/ be und]/ood by ref]r+ to ! accompany+ figures4 ,figs4 #aj-ad1 = in/ance1 %[ ! microscopic appe>ance ( sev]al plant tissues4 ,illu/ration3 ,,fig4 #aj4--;,cells at a root tip4 ,illu/ration3 ,,fig4 #aa4--,section ( a leaf %[+ cells ( diff]5t %apes4 ,at ,fig4 #aj w be se5 ! tip ( a root1 pla9ly made ( cells q simil> to ! typical cell describ$4 ,at ,fig4 #aa w be se5 a bit ( a leaf %[+ ! same g5]al /ructure4 ,at ,fig4 #ab is a bit ( plant tissue ( :i* ! cell walls are v ?ick1 s t a v d5se /ructure is =m$4 ,at ,fig4 #ac is a bit ( a potato %[+ its cells fill$ ) small granules ( />* :i* ! cells h produc$ by _! activities & deposit$ )9 _! own bodies4 ,at ,fig4 #ad are sev]al wood cells %[+ cell walls ( diff]5t %ape :i*1 hav+ become dead1 h lo/ _! cont5ts & simply rema9 z dead cell walls4 ,ea* 0 9 its e>li] hi/ory fill$ ) cell sub/ance & conta9$ a nucleus4 ,9 a simil> way any bit ( vegetable tissue w\ld readily %[ itself to be made ( simil> cells4 ,9 animal tissues ! cellul> /ructure is n s easily se51 l>gely because ! products made by ! cells1 ! =m$ products1 become relatively m abundant & ! cells !mselves n s prom95t4 ,b ! cellul> /ructure is none ! less demon/rable4 ,9 ,fig4 #ae1 = in/ance1 w be se5 a bit ( c>tilage :]e ! cells !mselves are r small1 :ile ! mat]ial deposit$ betwe5 !m is abundant4 ,?is mat]ial betwe5 ! cells is really to be reg>d$ z an excessively ?ick5$ cell wall & has be5 secret$ by ! cell sub/ance ly+ )9 ! cells1 s t a bit ( c>tilage is really a mass ( cells ) an exceptionally ?ick cell wall4 ,at ,fig4 #af is %[n a little blood4 ,"h ! cells are to be se5 float+ 9 a liquid4 ,! liquid is col\rless & x is ! r$ col\r 9 ! blood cells :i* gives ! blood its r$ col\r4 ,! liquid may "h aga9 be reg>d$ z mat]ial produc$ by cells4 ,at ,fig4 #ag is a bit ( bone %[+ small irregul> cells imb$d$ )9 a l>ge mass ( mat]ial :i* has be5 deposit$ by ! cell4 ,9 ?is case ! =m$ mat]ial has be5 h>d5$ by calcium phosphate1 :i* gives ! rigid consi/5cy to ! bone4 ,9 "s animal tissues ! =m$ mat]ial is /ill great] 9 am\nt4 ,at ,fig4 #ah1 = example1 is a bit ( connective tissue1 made up ( a mass ( f9e fibres :i* h no resemblance to cells1 & inde$ are n cells4 ,^! fibres h1 h[ev]1 be5 made by cells1 & a c>eful /udy ( su* tissue at prop] places w %[ ! cells )9 x4 ,! cells %[n 9 ,fig4 #ah 7c7 h secret$ ! fibr\s mat]ial4 ,fig4 #ai %[s a cell compos+ a bit ( n]ve4 ,at ,fig4 #bj is a bit ( muscle2 ! only trace ( cellul> /ructure t x %[s is 9 ! nuclei 7n71 b if ! muscle be /udi$ 9 a "y condition its cellul> /ructure is m evid5t4 ,?us x happ5s 9 adult animals t ! cells :i* are l>ge & cle> at fir/1 become less & less evid5t1 until ! adult tissue seems sometimes to be compos$ mo/ly ( :at we h call$ =m$ mat]ial4 ,illu/ration3 ,,fig4 #ab4--,plant cells ) ?ick walls1 f a f]n4 ,illu/ration3 ,,fig4 #ac4--,section ( a potato %[+ diff]5t %ap$ cells1 ! inn] & l>g] ones be+ fill$ ) gra9s ( />*4 ,illu/ration3 ,,fig4 #ad4--,v>i\s %ap$ wood cells f plant tissue4 ,illu/ration3 ,,fig4 #ae4--;,a bit ( c>tilage4 ,illu/ration3 ,,fig4 #af4--;,frog's blood3 a & b are ! cells2 c is ! liquid4 ,illu/ration3 ,,fig4 #ag4--;,a bit ( bone1 %[+ ! cells imb$d$ 9 ! bony matt]4 ,x mu/ n be imag9$1 h[ev]1 t a v rigid l9e c be drawn betwe5 ! cell itself & ! mat]ial x =ms4 ,! =m$ mat]ial is 9 _m cases simply a ?ick5$ cell wall1 & ?is we commonly reg>d z "p ( ! cell4 ,9 _m cases ! =m$ mat]ial is simply ! old dead cell walls f :i* ! liv+ sub/ance has be5 )drawn 7,fig4 #ad74 ,9 o!r cases ! cell sub/ance acquires peculi> functions1 s t :at seems to be ! =m$ mat]ial is really a modifi$ cell body & is /ill active & alive4 ,su* is ! case 9 ! muscle4 ,9 o!r cases ! =m$ mat]ial appe>s to be manufactur$ )9 ! cell & secret$1 z 9 ! case ( bone4 ,no %>p l9es c be drawn1 h[ev]1 betwe5 ! v>i\s types4 ,b ! di/9ction betwe5 =m$ mat]ial & cell body is a conv5i5t "o & may well be reta9$ 9 ! discussion ( cells4 ,9 our discussion ( ! fundam5tal vital prop]ties we are only conc]n$ 9 ! cell sub/ance1 ! =m$ mat]ial hav+ no?+ to d ) fundam5tal activities ( life1 al?\gh x =ms l>gely ! second>y ma*9]y :i* we h already /udi$4 ,illu/ration3 ,,fig4 #ah4--;,connective tissue4 ,! cells ( ! tissue are %[n at c1 & ! fibres or =m$ matt] at f4 ,9 all high] animals & plants ! life ( ! individual beg9s z a s+le ovum or a s+le cell1 & z x gr[s ! cells increase rapidly until ! adult is =m$ out ( hundr$s ( millions ( cells4 ,z ^! cells become num]\s !y cease1 aft] a little1 to be alike4 ,!y assume diff]5t %apes :i* are adapt$ to ! diff]5t duties !y are to p]=m4 ,?us1 ^? cells :i* are to =m bone soon become diff]5t f ^? :i* are to =m muscle1 & ^? :i* are to =m ! blood are q unlike ^? :i* are to produce ! hairs4 ,by means ( su* a diff]5tiation !re arises a v complex mass ( cells1 ) great v>iety 9 %ape & function4 ,illu/ration3 ,,fig4 #ai4 ,a piece ( n]ve fibre1 %[+ ! cell ) its nucleus at n4 ,x %\ld be notic$ fur!r t !re are "s animals & plants 9 :i* ! :ole animal is compos$ ( a s+le cell4 ,^! organisms are usually ( extremely m9ute size1 & !y comprise mo/ ( ! s-call$ animalcul :i* are f\nd 9 wat]4 ,9 su* animals ! diff]5t p>ts ( ! cell are modifi$ to p]=m diff]5t functions4 ,! diff]5t organs appe> )9 ! cell1 & ! cell is m complex ?an ! typical cell describ$4 ,fig4 #ba %[s su* a cell4 ,su* an animal possesses sev]al organs1 b1 s9ce x consi/s ( a s+le mass ( protoplasm & a s+le nucleus1 x is /ill only a s+le cell4 ,9 ! multicellul> organisms ! organs ( ! body are made up ( cells1 & ! diff]5t organs are produc$ by a diff]5tiation ( cells1 b 9 ! unicellul> organisms ! organs are ! results ( ! diff]5tiation ( ! p>ts ( a s+le cell4 ,9 ! "o case !re is a diff]5tiation ( cells1 & 9 ! o!r ( ! p>ts ( a cell4 ,illu/ration3 ,,fig4 #bj4--;,a muscle fibre4 ,! nucleii are %[n at n4 ,illu/ration3 ,,fig4 #ba4--;,a complex cell4 ,x is an entire animal1 b compos$ ( only "o cell4 ,su*1 9 brief1 is ! cell to ^: activities x is possible to trace ! fundam5tal prop]ties ( all liv+ ?+s4 ,cells are end[$ ) ! prop]ties ( irritability1 contractibility1 assimilation & reproduction1 & x is ?us pla9ly to ! /udy ( cells t we mu/ look = an int]pretation ( life ph5om5a4 ,if we c rea* an intelligible und]/&+ ( ! activities ( ! cell our problem is solv$1 = ! activities ( ! fully =m$ animal or plant1 h[ev] complex1 are simply ! application ( me*anical & *emical pr9ciples among ! gr\ps ( su* cells4 ,b :]e9 does ?is k ( cells help u8 ,are we any ne>] to und]/&+ h[ ^! vital processes arise8 ,9 answ] to ?is "q we may fir/ ask :e!r x is possible to det]m9e :e!r any "o "p ( ! cell is ! seat ( its activities4 ,! ,cell ,wall4--,! fir/ sugge/ion :i* arose 0 t ! cell wall 0 ! important "p ( ! cell1 ! o!rs be+ second>y4 ,?is 0 n an unnatural conclusion4 ,! cell wall is ! mo/ p]si/5t "p ( ! cell4 ,x 0 ! "p fir/ discov]$ by ! microscope & is ! "p :i* rema9s aft] ! o!r p>ts are gone4 ,inde$1 9 _m ( ! s-call$ cells ! cell wall is all t is se51 ! cell cont5ts hav+ disappe>$ 7,fig4 #ad74 ,x 0 n /range1 !n1 t ?is %\ld at fir/ h be5 look$ ^u z ! prim>y "p4 ,! idea 0 t ! cell wall 9 "s way *ang$ ! *emical "* ( ! sub/ances 9 contact ) its two sides1 & ?us gave rise to vital activities :i*1 z we h se51 are fundam5tally *emical4 ,?us ! cell wall 0 reg>d$ z ! mo/ ess5tial "p ( ! cell1 s9ce x controll$ its activities4 ,?is ! belief ( ,s*wann1 al?\gh he also reg>d$ ! o!r p>ts ( ! cell z ( importance4 ,illu/ration3 ,,fig4 #bb4--;,an amoeba4 ,a s+le cell )\t cell wall4 n is ! nucleus2 f1 a bit ( food :i* ! cell has absorb$4 ,?is conception1 h[ev]1 0 q tempor>y4 ,x 0 mu* z if our hypo!tical supramundane obs]v] look$ ^u ! clo!s ( 8 newly discov]$ human be+ z =m+ ! ess5tial "p ( 8 nature4 ,x 0 soon evid5t t ?is position c\ld n be ma9ta9$4 ,x 0 f\nd t _m bits ( liv+ matt] 7 entirely de/itute ( cell wall4 ,?is is especially true ( animal cells4 ,:ile among plants ! cell wall is almo/ always well develop$1 x is v common = animal cells to be entirely lack+ 9 ?is ext]nal cov]+--z1 = example1 ! :ite blood-cells4 ,fig4 #bb %[s an amoeba1 a cell ) v active p[]s ( motion & assimilation1 b ) no cell wall4 ,moreov]1 "y cells are always m active ?an old] ones1 & !y commonly possess ei!r no cell wall or a v slight "o1 ?is be+ deposit$ z ! cell becomes old] & rema9+ long aft] x is dead4 ,su* facts soon disprov$ ! notion t ! cell wall is a vital "p ( ! cell1 & a new conception took its place :i* 0 to h a m pr(\nd influ5ce ^u ! /udy ( liv+ ?+s ?an any discov]y hi!rto made4 ,?is 0 ! =mulation ( ! doctr9e ( ! nature ( protoplasm4 ,protoplasm4--7a7 ,discov]y4 ,z x became evid5t t ! cell wall is a some:at inactive "p ( ! cell1 m att5tion 0 put on ! cell cont5ts4 ,= tw5ty ye>s aft] ! =mulation ( ! cell doctr9e bo? ! cell sub/ance & ! nucleus _h be5 look$ ^u z ess5tial to its activities4 ,?is 0 m especially true ( ! nucleus1 :i* _h be5 ?\ght ( z an organ ( reproduction4 ,^! sugge/ions appe>$ indef9itely 9 ! writ+s ( "o sci5ti/ & ano!r1 & 7 f9ally =mulat$ 9 #ahfj into a g5]al !ory :i* =m$ :at has sometimes be5 call$ ! />t+ po9t ( mod]n biology4 ,f t "t ! mat]ial kn[n z protoplasm 0 elevat$ into a prom95t position 9 ! discussion ( all subjects connect$ ) liv+ ph5om5a4 ,! idea ( protoplasm 0 fir/ cle>ly def9$ by ,s*ultze1 :o claim$ t ! real active "p ( ! cell 0 ! cell sub/ance )9 ! cell wall4 ,?is sub/ance he prov$ to be end[$ ) p[]s ( motion & p[]s ( induc+ *emical *anges associat$ ) vital ph5om5a4 ,he %[$ x to be ! mo/ abundant 9 ! mo/ active cells1 becom+ less abundant z ! cells lose _! activity1 & disappe>+ :5 ! cells lose _! vitality4 ,?is cell sub/ance 0 soon rais$ into a position ( su* importance t ! small] body )9 x 0 obscur$1 & = "s tw5ty ye>s m ! nucleus 0 sil5tly ignor$ 9 biological discussion4 ,accord+ to ,s*ultze1 ! cell sub/ance itself con/itut$ ! cell1 ! o!r p>ts be+ entirely subord9ate1 & inde$ frequ5tly abs5t4 ,a cell 0 ?us a bit ( protoplasm1 & no?+ m4 ,b ! m important feature ( ?is doctr9e 0 n ! simple conclusion t ! cell sub/ance con/itutes ! cell1 b ! m sweep+ conclusion t ?is cell sub/ance is 9 all cells ess5tially id5tical4 ,! /udy ( all animals1 high & l[1 %[$ all active cells fill$ ) a simil> mat]ial1 & m important /ill1 ! /udy ( plant cells disclos$ a mat]ial /rik+ly simil>4 ,s*ultze exp]im5t$ ) ?is mat]ial by all means at 8 comm&1 & f9d+ t ! cell sub/ance 9 all animals & plants obeys ! same te/s1 rea*$ ! conclusion t ! cell sub/ance 9 animals & plants is always id5tical4 ,to ?is mat]ial he n[ gave ! "n protoplasm1 *oos+ a "n hi!rto giv5 to ! cell cont5ts ( plant cells4 ,f ?is "t =? ?is t]m protoplasm 0 appli$ to ! liv+ mat]ial f\nd 9 all cells1 & became at once ! mo/ important factor 9 ! discussion ( biological problems4 ,! importance ( ?is newly =mulat$ doctr9e x is difficult to appreciate4 ,"h1 9 protoplasm _h be5 app>5tly f\nd ! f\ndation ( liv+ ph5om5a4 ,"h 0 a sub/ance univ]sally pres5t 9 animals & plants1 simple & uni=m--a sub/ance always pres5t 9 liv+ p>ts & disappe>+ ) dea?4 ,x 0 ! simple/ ?+ t _h life1 & inde$ ! only ?+ t _h life1 = !re is no life outside ( cells & protoplasm4 ,b simple z x 0 x _h all ! fundam5tal prop]ties ( liv+ ?+s--irritability1 contractibility1 assimilation1 & reproduction4 ,x 0 a comp\nd :i* seem+ly des]v$ ! "n ( physical basis ( life1 :i* 0 soon giv5 to x by ,huxley4 ,) ?is conception ( protoplasm z ! physical basis ( life ! problems connect$ ) ! /udy ( life became m simplifi$4 ,9 ord] to /udy ! nature ( life x 0 no long] necess>y to /udy ! confus+ mass ( complex organs disclos$ to u by animals & plants1 or ev5 ! some:at less confus+ /ructures %[n by individual cells4 ,ev5 ! simple cell has sev]al sep>ate p>ts capable ( und]go+ great modifications 9 diff]5t types ( animals4 ,?is confusion n[ appe>$ to vani%1 = only "o ?+ 0 f\nd to be alive1 & t 0 app>5tly v simple4 ,b t sub/ance exhibit$ all ! prop]ties ( life4 ,x mov$1 x c\ld gr[1 & reproduce itself1 s t x 0 necess>y only to expla9 ?is sub/ance & life w\ld be expla9$4 7b7 ,nature ( ,protoplasm4--,:at is ?is mat]ial1 protoplasm8 ,z disclos$ by ! e>ly microscope x appe>$ to be no?+ m ?an a simple mass ( jelly1 usually transp>5t1 m or less consi/5t1 sometimes be+ q fluid1 & at o!rs m solid4 ,/ructure x appe>$ to h none4 ,its *ief peculi>ity1 s f> z physical *>act]s 7 conc]n$1 0 a wond]ful & nev]-ceas+ activity4 ,?is jellylike mat]ial appe>$ to be end[$ ) wond]ful p[]s1 & yet nei!r physical nor microscopical /udy reveal$ at fir/ any?+ m ?an a uni=m homog5e\s mass ( jelly4 ,*emical /udy ( ! same sub/ance 0 ( no less int]e/ ?an ! microscopical /udy4 ,( c\rse x 0 no easy matt] to collect ?is protoplasm 9 suffici5t quantity & pure en\gh to make a c>eful analysis4 ,! difficulties 7 9 "t1 h[ev]1 ov]come1 & *emical /udy %[$ protoplasm to be a proteid1 relat$ to o!r proteids l album51 b "o :i* 0 m complex ?an any o!r kn[n4 ,x 0 = a long "t look$ ^u by _m z a s+le def9ite *emical comp\nd1 & attempts 7 made to det]m9e its *emical =mula4 ,su* an analysis indicat$ a molecule made up ( sev]al hundr$ atoms4 ,*emi/s did n1 h[ev]1 look ) mu* confid5ce ^u ^! results1 & x is n surpris+ t !re 0 no v close agreem5t among !m z to ! numb] ( atoms 9 ?is suppos$ complex molecule4 ,moreov]1 f ! v fir/1 "s biologi/s ?\ght protoplasm to be n "o1 b m likely a mixture ( sev]al sub/ances4 ,b al?\gh x 0 m complex ?an any o!r sub/ance /udi$1 its g5]al *>act]s 7 s l ^? ( album5 t x 0 uni=mly reg>d$ z a proteid2 b "o :i* 0 ( a high] complexity ?an o!rs1 =m+ p]haps ! highe/ numb] ( a s]ies ( complex *emical comp\nds1 ( :i* ord9>y proteids1 su* z album51 =m$ l[] memb]s4 ,?us1 )9 a few ye>s foll[+ ! discov]y ( protoplasm !re _h develop$ a !ory t liv+ ph5om5a are due to ! activities ( a def9ite ?\gh complex *emical comp\nd1 compos$ *iefly ( ! elem5ts c>bon1 oxyg51 hydrog51 & nitrog51 & closely relat$ to ord9>y proteids4 ,?is sub/ance 0 ! basis ( liv+ activity1 & to its modification "u diff]5t conditions 7 due ! miscellane\s ph5om5a ( life4 7c7 ,significance ( ,protoplasm4--,! philosophical significance ( ?is conception 0 v f>-rea*+4 ,! problem ( life 0 s simplifi$ by sub/itut+ ! simple protoplasm = ! complex organism t its solution seem$ to be n v difficult4 ,?is idea ( a *emical comp\nd z ! basis ( all liv+ ph5om5a gave rise 9 a %ort "t to a *emical !ory ( life :i* 0 at lea/ t5able1 & :i* acc\nt$ = ! fundam5tal prop]ties ( life4 ,t !ory1 ! *emical !ory ( life1 may be outl9$ some:at z foll[s3 ,! /udy ( ! *emical nature ( sub/ances d]iv$ f liv+ organisms has develop$ into :at has be5 call$ organic *emi/ry4 ,organic *emi/ry has %[n t x is possible to manufacture artificially _m ( ! comp\nds :i* are call$ organic1 & :i* _h be5 hi!rto reg>d$ z produc$ only by liv+ organisms4 ,at ! beg9n+ ( ! c5tury1 x 0 suppos$ to be impossible to manufacture by artificial means any ( ! comp\nds :i* animals & plants produce z ! result ( _! life4 ,b *emi/s 7 n long 9 %[+ t ?is position is unt5able4 ,_m ( ! organic products 7 soon %[n capable ( production by artificial means 9 ! *emi/'s laboratory4 ,^! organic comp\nds =m a s]ies beg9n+ ) su* simple bodies z c>bonic acid 7,,co#b71 wat] 7,h#b,o71 & ammonia 7,,nh#c71 & pass+ up ?r\gh a l>ge numb] ( memb]s ( great] & great] complexity1 all compos$1 h[ev]1 *iefly ( ! elem5ts c>bon1 oxyg51 hydrog51 & nitrog54 ,our *emi/s f\nd t />t+ ) simple sub/ances !y c\ld1 by prop] means1 comb9e !m into molecules ( great] complexity1 & 9 s do+ c\ld make _m ( ! comp\nds t _h hi!rto be5 produc$ only z a result ( liv+ activities4 ,= example1 urea1 =mic acid1 indigo1 & _m o!r bodies1 hi!rto produc$ only by animals & plants1 7 easily produc$ by ! *emi/ by purely *emical me?ods4 ,n[ :5 protoplasm _h be5 discov]$ z ! physical basis ( life1 &1 :5 x 0 fur!r conceiv$ t ?is sub/ance is a proteid relat$ to album5s1 x 0 inevitable t a !ory %\ld arise :i* f\nd ! explanation ( life 9 accordance ) simple *emical laws4 ,if1 z *emi/s & biologi/s !n believe1 protoplasm is a comp\nd :i* /&s at ! head ( ! organic s]ies1 & if1 z is ! fact1 *emi/s are ea* ye> succe$+ 9 mak+ high] & high] memb]s ( ! s]ies1 x is an easy assumption t "s day !y w be able to make ! highe/ memb] ( ! s]ies4 ,fur!r1 x is a well-kn[n fact t simple *emical comp\nds h simple physical prop]ties1 :ile ! high] ones h m v>i$ prop]ties4 ,wat] has ! prop]ty ( be+ liquid at c]ta9 temp]atures & solid at o!rs1 & ( divid+ into small p>ticles 7i4e41 dissolv+7 c]ta9 bodies br\ght 9 contact ) x4 ,! high] comp\nd album5 has1 h[ev]1 a great numb] ( prop]ties & possibilities ( comb9ation f> beyond ^? ( wat]4 ,n[ if ! prop]ties increase 9 complexity ) ! complexity ( ! comp\nd1 x is aga9 an easy assumption t :5 we rea* a comp\nd z complex z protoplasm1 x w h prop]ties z complex z ^? ( ! simple life sub/ance4 ,nor 0 ?is su* a v wild hypo!sis4 ,aft] all1 ! fundam5tal life activities may all be trac$ to ! simple oxidation ( food1 = ?is results 9 movem5t1 assimilation1 & gr[?1 & ! result ( gr[? is reproduction4 ,x 0 !re=e only necess>y = our biological *emi/s to suppose t _! *emical comp\nd protoplasm possess$ ! p[] ( caus+ c]ta9 k9ds ( oxidation to take place1 j z wat] itself induces a simpl] k9d ( oxidation1 & !y w\ld h a me*anical explanation ( ! life activities4 ,x 0 c]ta9ly n a v absurd assumption to make1 t ?is sub/ance protoplasm c\ld h ?is p[]1 & f ?is ! o!r vital activities are easily d]iv$4 ,9 o!r words1 ! =mulation ( ! doctr9e ( protoplasm made x possible to assume t life is n a di/9ct =ce1 b simply a "n giv5 to ! prop]ties possess$ by t highly complex *emical comp\nd protoplasm4 ,j z we might give ! "n aquacity to ! prop]ties possess$ by wat]1 s we h actually giv5 ! "n vitality to ! prop]ties possess$ by protoplasm4 ,to be sure1 vitality is m m>vel\s ?an aquacity1 b s is protoplasm a m complex comp\nd ?an wat]4 ,?is comp\nd 0 a v un/able comp\nd1 j z is a mass ( gunp[d]1 & h5ce x is highly irritable1 also l gunp[d]1 & any di/urbance ( its condition produces motion1 j z a sp>k w d 9 a mass ( gunp[d]4 ,x is capable ( induc+ oxidation 9 foods1 some?+ z wat] induces oxidation 9 a bit ( iron4 ,! oxidation is1 h[ev]1 ( a diff]5t k9d1 & results 9 ! =mation ( diff]5t *emical comb9ations2 b x is ! basis ( assimilation4 ,s9ce n[ assimilation is ! f\ndation ( gr[? & reproduction1 ?is me*anical !ory ( life ?us succe$$ 9 trac+ to ! simple prop]ties ( ! *emical comp\nd protoplasm1 all ! fundam5tal prop]ties ( life4 ,s9ce fur!r1 z we h se5 9 our fir/ *apt]1 ! m complex prop]ties ( high] organisms are easily d$uc$ f ^! simple ones by ! application ( ! laws ( me*anics1 we h "h 9 ?is me*anical !ory ( life ! complete r$uction ( ! body to a ma*9e4 ,! ,reign ( ,protoplasm4--,?is sub/ance protoplasm became n[ naturally ! c5tre ( biological ?\ght4 ,! !ory ( protoplasm arose at ab\t ! same "t t ! doctr9e ( evolution began to be s]i\sly discuss$ "u ! /imulus ( ,d>w91 & naturally ^! two great conceptions develop$ side by side4 ,evolution 0 con/antly tea*+ t natural =ces are suffici5t to acc\nt = _m ( ! complex ph5om5a :i* _h hi!rto be5 reg>d$ z insolvable2 & :at m natural ?an ! same k9d ( ?9k+ %\ld be appli$ to ! vital activities manife/$ by ?is sub/ance protoplasm4 ,:ile ! /udy ( plants & animals 0 %[+ sci5ti/s t natural =ces w\ld expla9 ! orig9 ( m complex types f simpl] ones ?r\gh ! law ( natural selection1 "h 9 ?is conception ( protoplasm 0 a !ory :i* promis$ to %[ h[ ! simple/ =ms may h be5 d]iv$ f ! non-liv+4 ,= an explanation ( ! orig9 ( life by natural means appe>$ n[ to be a simple matt]4 ,x requir$ n[ no viol5t /ret* ( ! imag9ation to expla9 ! orig9 ( life some?+ z foll[s3 ,we "k t ! *emical elem5ts h c]ta9 aff9ities = ea* o!r1 & w unite ) ea* o!r "u prop] conditions4 ,we "k t ! me?ods ( union & ! result+ comp\nds v>y ) ! conditions "u :i* ! union takes place4 ,we "k fur!r t ! elem5ts c>bon1 hydrog51 oxyg51 & nitrog5 h mo/ rem>kable prop]ties1 & unite to =m an almo/ endless s]ies ( rem>kable bodies :5 br\ght into comb9ation "u diff]5t conditions4 ,we "k t by v>y+ ! conditions ! *emi/ c =ce ^! elem5ts to unite into a mo/ extraord9>y v>iety ( comp\nds ) an equal v>iety ( prop]ties4 ,:at m natural1 !n1 ?an ! assumption t "u c]ta9 conditions ^! same elem5ts w\ld unite 9 su* a way z to =m ?is comp\nd protoplasm2 & !n1 if ! ideas conc]n+ protoplasm 7 correct1 ?is body w\ld %[ ! prop]ties ( protoplasm1 & !re=e be alive4 ,c]ta9ly su* a supposition 0 n absurd1 & view$ 9 ! light ( ! rapid advance 9 ! manufacture ( organic comp\nds c\ld h>dly be call$ improbable4 ,*emi/s beg9n+ ) simple bodies l ,,co#b & ,h#b,o 7 climb+ ! ladd]1 ea* r\nd ( :i* 0 repres5t$ by comp\nds ( high] complexity4 ,at ! top 0 protoplasm1 & ea* ye> saw our *emi/s ne>] ! top ( ! ladd]1 & ?us approa*+ protoplasm z _! f9al goal4 ,!y n[ began to pr$ict t only a few m ye>s w\ld be requir$ = *emi/s to discov] ! prop] conditions1 & ?us make protoplasm4 ,z late z #ahhj ! pr$iction 0 freely made t ! next great discov]y w\ld be ! manufacture ( a bit ( protoplasm by artificial means1 & ?us 9 ! artificial production ( life4 ,! rapid advance 9 organic *emi/ry r5d]$ ?is pr$iction ea* ye> m & m probable4 ,! ability ( *emi/s to manufacture *emical comp\nds appe>$ to be unlimit$1 & ! only "q 9 reg>d to _! ability to make protoplasm ?us resolv$ itself into ! "q ( :e!r protoplasm is really a *emical comp\nd4 ,we c easily und]/& h[ eag] biologi/s became n[ 9 pursuit ( ! goal :i* seem$ almo/ )9 _! rea*2 h[ int]e/$ !y 7 9 any new discov]y1 & h[ eag]ly !y s\ght = l[] & simpl] types ( protoplasm s9ce ^! w\ld be a /ep ne>] to ! e>lie/ undiff]5tiat$ life sub/ance4 ,inde$ s eag] 0 ?is pursuit = pure undiff]5tiat$ protoplasm1 t x l$ to "o ( ^? unf\nd$ discov]ies :i* "t %[$ to be purely imag9>y4 ,:5 ?is reign ( protoplasm 0 at its height & biologi/s 7 seek+ = ev5 great] simplicity a mo/ a/\nd+ discov]y 0 ann\nc$4 ,! ,briti% explor+ %ip ,*all5g] _h return$ f its voyage ( discov]y & collection1 & its v>i\s treasures 7 turn$ ov] to ! diff]5t sci5ti/s = /udy4 ,! brilliant ,pr(4 ,huxley1 :o _h fir/ =mulat$ ! me*anical !ory ( life1 n[ />tl$ ! biological _w ) ! /atem5t t ^! collections _h %[n him t at ! bottom ( ! deep sea1 9 c]ta9 p>ts ( ! _w1 !re exi/s a diffus$ mass ( liv+ undiff]5tiat$ protoplasm4 ,s simple & undiff]5tiat$ 0 x t x 0 n divid$ into cells & conta9$ no nucleii4 ,x 01 9 %ort1 exactly ! k9d ( primitive protoplasm :i* ! evolutioni/ want$ to complete 8 *a9 ( liv+ /ructures1 & ! biologi/ want$ to s]ve z a f\ndation = 8 me*anical !ory ( life4 ,if su* a diffus$ mass ( undiff]5tiat$ protoplasm exi/$ at ! bottom ( ! sea1 "o c\ld h>dly d\bt t x 0 develop$ !re by "s purely natural =ces4 ,! discov]y 0 a />tl+ "o1 = x seem$ t ! actual />t+ po9t ( life _h be5 rea*$4 ,huxley nam$ 8 sub/ance ,ba?ybias1 & ?is "n became 9 a %ort "t famili> to e "o :o 0 ?9k+ ( ! problems ( life4 ,b ! discov]y 0 suspect$ f ! fir/1 because x 0 too closely 9 accord ) speculation1 & x 0 soon disprov$4 ,its discov]] soon aft] c\rage\sly ann\nc$ to ! _w t he _h be5 entirely mi/ak51 & t ! ,ba?ybias1 s f> f be+ undiff]5tiat$ protoplasm1 0 n an organic product at all1 b simply a m9]al deposit 9 ! sea wat] made by purely artificial means4 ,ba?ybias /&s !re=e z an in/ance ( a too precipitate advance 9 speculation1 :i* l$ ev5 su* a brilliant man z ,pr(4 ,huxley into an un=tunate error ( obs]vation2 =1 beyond "q1 he w\ld nev] h made su* a mi/ake _h he n be5 dom9at$ by 8 speculative !ories z to ! nature ( protoplasm4 ,b al?\gh ,ba?ybias prov$ delusive1 ?is did n mat]ially affect ! advance & developm5t ( ! doctr9e ( protoplasm4 ,simple =ms ( protoplasm 7 f\nd1 al?\gh none q s simple z ! hypo!tical ,ba?ybias4 ,! univ]sal pres5ce ( protoplasm 9 ! liv+ p>ts ( all animals & plants & its manife/ activities completely demon/rat$ t x 0 ! only liv+ sub/ance1 & z ! result ( a few ye>s ( exp]im5t & ?\ght ! biologi/'s conception ( life cry/alliz$ into some?+ l ?is3 ,liv+ organisms are made ( cells1 b ^! cells are simply m9ute indep5d5t bits ( protoplasm4 ,!y may conta9 a nucleus or !y may n1 b ! ess5ce ( ! cell is ! protoplasm1 ?is alone hav+ ! fundam5tal activities ( life4 ,^! bits ( liv+ matt] aggregate !mselves toge!r into gr\ps to =m colonies4 ,su* colonies are animals or plants4 ,! cells divide ! "w ( ! colony among !mselves1 ea* cell adopt+ a =m be/ adapt$ = ! special "w x has to d4 ,! animal or plant is ?us simply an aggregate ( cells1 & its activities are ! sum ( ! activities ( its sep>ate cells2 j z ! activities ( a city are ! sum ( ! activities ( its individual inhabitants4 ,! bit ( protoplasm 0 ! unit1 & ?is 0 a *emical comp\nd or a simple mixture ( comp\nds to ^: comb9$ physical prop]ties we h giv5 ! "n vitality4 ,! ,decl9e ( ! ,reign ( ,protoplasm4--,h>dly _h ?is extreme *emical !ory ( life be5 cle>ly conceiv$ be=e accumulat+ facts began to %[ t x is unt5able & t x mu/ at lea/ be va/ly modifi$ be=e x c be receiv$4 ,! f\ndation ( ! *emical !ory ( life 0 ! conception t protoplasm is a def9ite ?\gh complex *emical comp\nd4 ,b aft] a few ye>s' /udy x appe>$ t su* a conception ( protoplasm 0 incorrect4 ,x _h long be5 suspect$ t protoplasm 0 m complex ?an 0 at fir/ ?\ght4 ,x 0 n ev5 at ! outset f\nd to be p]fectly homog5e\s1 b 0 se5 to conta9 m9ute granules1 toge!r ) bodies ( l>g] size4 ,al?\gh ^! bodies 7 se5 !y 7 reg>d$ z accid5tal or second>y1 & 7 n ?\ght ( z =m+ any s]i\s objection to ! conception ( protoplasm z a def9ite *emical comp\nd4 ,b mod]n opticians improv$ _! microscopes1 & microscopi/s greatly improv$ _! me?ods4 ,) ! new microscopes & new me?ods !re began to appe>1 ab\t tw5ty ye>s ago1 new revelations 9 reg>d to ?is protoplasm4 ,its lack ( homog5eity became m evid5t1 until !re has f9ally be5 disclos$ to u ! significant fact t protoplasm is to be reg>d$ z a sub/ance n only ( *emical b also ( high me*anical complexity4 ,! idea ( ?is mat]ial z a simple homog5e\s comp\nd or z a mixture ( su* comp\nds is absolutely fallaci\s4 ,protoplasm is to-day kn[n to be made up ( p>ts h>moni\sly adapt$ to ea* o!r 9 su* a way z to =m an extraord9>ily intricate ma*9e2 & ! microscopi/ ( to-day recognizes cle>ly t ! activities ( ?is mat]ial mu/ be reg>d$ z ! result ( ! ma*9]y :i* makes up protoplasm r ?an z ! simple result ( its *emical composition4 ,protoplasm is a ma*9e & n a *emical comp\nd4 ,illu/ration3 ,,fig4 #bc4--;,a cell z x appe>s to ! mod]n microscope4 a1 protoplasmic reticulum2 b1 liquid 9 its me%es2 c1 nucle> membrane2 d1 nucle> reticulum2 e1 *romat9 reticulum2 f1 nucleolus2 g1 c5trosome2 h1 c5trosph]e2 i1 vacuole2 j1 in]t bodies4 ,/ructure ( ,protoplasm4--,! /ructure ( protoplasm is n yet ?or\ghly und]/ood by sci5ti/s1 b a few g5]al facts are kn[n beyond "q4 ,x is ?\ght1 9 ! fir/ place1 t x consi/s ( two q diff]5t sub/ances4 ,!re is a some:at solid mat]ial p]meat+ x1 usually1 reg>d$ z hav+ a reticulate /ructure4 ,x is v>i\sly describ$1 sometimes z a reticulate network1 sometimes z a mass ( ?reads or fibres1 & sometimes z a mass ( foam 7,fig4 #bc1 a74 ,x is extremely delicate & only visible "u special conditions & ) ! be/ ( microscopes4 ,only "u peculi> conditions c x be se5 9 protoplasm :ile alive4 ,!re is no "q1 h[ev]1 t all protoplasm is p]meat$ :5 alive by a m9ute delicate mass ( mat]ial1 :i* may take ! =m ( ?reads or fibres or may assume o!r =ms4 ,)9 ! me%es ( ?is ?read or reticulum !re is f\nd a liquid1 p]fectly cle> & transp>5t1 to ^: pres5ce ! liquid "* ( ! protoplasm is due 7,fig4 #bc1 b74 ,9 ?is liquid no /ructure c be det]m9$1 &1 s f> z we "k1 x is homog5e\s4 ,/ill fur!r /udy discloses o!r complexities4 ,x appe>s t ! fibr\s mat]ial is always m>k$ by ! pres5ce ( excessively m9ute bodies1 :i* h be5 call$ by v>i\s names1 b :i* we w speak ( z microsomes4 ,sometimes1 inde$1 ! fibres !mselves appe> almo/ l /r+s ( beads1 s t !y h be5 describ$ z made up ( r[s ( m9ute elem5ts4 ,x is immat]ial = our purpose1 h[ev]1 :e!r ! fibres are to be reg>d$ z made up ( microsomes or n4 ,?is mu* is sure1 t ^! microsomes --granules ( excessive m9ut5ess--occur 9 protoplasm & are closely connect$ ) ! fibres 7,fig4 #bc1 a74 ,! ,nucleus4--7a7 ,pres5ce ( a ,nucleus4--,if protoplasm has ?us become a new sub/ance 9 our m9ds z ! result ( ! discov]ies ( ! la/ tw5ty ye>s1 f> m m>vel\s h be5 ! discov]ies made 9 connection ) t body :i* has be5 call$ ! nucleus4 ,ev5 by ! e>ly microscopi/s ! nucleus 0 recogniz$1 & dur+ ! fir/ few ye>s ( ! cell doctr9e x 0 frequ5tly look$ ^u z ! mo/ active "p ( ! cell & z especially connect$ ) its reproduction4 ,! doctr9e ( protoplasm1 h[ev]1 s captivat$ ! m9ds ( biologi/s t = q a numb] ( ye>s ! nucleus 0 ignor$1 at lea/ 9 all discussions connect$ ) ! nature ( life4 ,x 0 a body 9 ! cell ^: pres5ce 0 unexpla9$ & :i* did n fall into accord ) ! g5]al view ( protoplasm z ! physical basis ( life4 ,= a :ile1 !re=e1 biologi/s gave little att5tion to x1 & 7 accu/om$ to speak ( x simply z a bit ( protoplasm a little m d5se ?an ! re/4 ,! cell 0 a bit ( protoplasm ) a small piece ( m d5se protoplasm 9 its c5tre appe>+ a little diff]5t f ! re/ & p]haps ! mo/ active "p ( ! cell4 ,z a result ( ?is excessive belief 9 ! effici5cy ( protoplasm ! "q ( ! pres5ce ( a nucleus 9 ! cell 0 = a :ile look$ ^u z "o ( comp>atively little importance4 ,_m cells 7 f\nd to h nucleii :ile o!rs did n %[ _! pres5ce1 & microscopi/s !re=e believ$ t ! pres5ce ( a nucleus 0 n necess>y to con/itute a cell4 ,a ,g]man naturali/ recogniz$ among l[] animals "o gr\p ^: di/9ctive *>act]i/ic 0 t !y 7 made ( cells )\t nucleii1 giv+ ! "n ,mon]a to ! gr\p4 ,z ! me?od ( /udy+ cells improv$ microscopi/s le>n$ bett] me?ods ( disc]n+ ! pres5ce ( ! nucleus1 & z x 0 done little by little !y began to f9d ! pres5ce ( nucleii 9 cells 9 :i* !y _h hi!rto n be5 se54 ,z microscopi/s n[ /udi$ "o aft] ano!r ( ^! animals & plants ^: cells _h be5 said to conta9 no nucleus1 !y began to f9d nucleii 9 !m1 until ! conclusion 0 f9ally rea*$ t a nucleus is a fundam5tal "p ( all active cells4 ,old cells :i* h lo/ _! activity may n %[ nucleii1 b1 s f> z we "k1 all active cells possess ^! /ructures1 & app>5tly no cell c c>ry on its activity )\t !m4 ,"s cells h sev]al nucleii1 & o!rs h ! nucle> matt] scatt]$ ?r\gh ! :ole cell in/ead ( be+ aggregat$ into a mass2 b nucle> matt] ! cell mu/ h to c>ry on its life4 ,illu/ration3 ,,fig4 #bd4--;,a cell cut into ?ree pieces1 ea* conta9+ a bit ( ! nucleus4 ,ea* cont9ues its life indef9itely1 soon acquir+ ! =m ( ! orig9al z at ,c4 ,lat] ! exp]im5t 0 made ( depriv+ cells ( _! nucleii1 & x /ill fur!r emphasiz$ ! importance ( ! nucleus4 ,among unicellul> animals are "s :i* are l>ge en\gh = direct manipulation1 & x is f\nd t if ^! cells are cut into pieces ! diff]5t pieces w behave v diff]5tly 9 accordance ) :e!r or n !y h )9 !m a piece ( ! nucleus4 ,all ! pieces are capable ( c>ry+ on _! life activities = a :ile4 ,! pieces ( ! cell :i* conta9 ! nucleus ( ! orig9al cell1 or ev5 a "p ( x1 are capable ( c>ry+ on all its life activities p]fectly well4 ,9 ,fig4 #bd is %[n su* a cell cut into ?ree pieces1 ea* ( :i* conta9s a piece ( ! nucleus4 ,ea* c>ries on its life activities1 fe$s1 gr[s & multiplies p]fectly well1 ! life processes seem+ to cont9ue z if no?+ _h happ5$4 ,q diff]5t is x ) fragm5ts :i* conta9 none ( ! nucleus 7,fig4 #be74 ,^! fragm5ts 7#a & #c71 ev5 ?\gh !y may be comp>atively l>ge masses ( protoplasm1 are incapable ( c>ry+ on ! functions ( _! life cont9u\sly4 ,= a :ile !y cont9ue to move ar\nd & app>5tly act l ! o!r fragm5ts1 b aft] a little _! life ceases4 ,!y are incapable ( assimilat+ food & incapable ( reproduction1 & h5ce _! life _c cont9ue v long4 ,facts l ^! demon/rate conclusively ! vital importance ( ! nucleus 9 cell activity1 & %[ u t ! cell1 ) its p[] ( cont9u$ life1 mu/ be reg>d$ z a comb9ation ( protoplasm ) its nucleus1 & _c exi/ )\t x4 ,x is n protoplasm1 b cell sub/ance1 plus cell nucleus1 :i* =ms ! simple/ basis ( life4 ,illu/ration3 ,,fig4 #be4--;,a cell cut into ?ree pieces1 only "o ( :i*1 ,no4 #b1 conta9s any nucleus4 ,?is fragm5t soon acquires ! orig9al =m & cont9ues its life indef9itely1 z %[n at ,b4 ,! o!r two pieces ?\gh liv+ = a "t1 die )\t reproduc+4 ,z m c>eful /udy ( protoplasm 0 made x soon became evid5t t !re is a v decid$ diff]5ce betwe5 ! nucleus & ! protoplasm4 ,! old /atem5t t ! nucleus is simply a bit ( d5se protoplasm is n true4 ,9 its *emical & physical composition z well z 9 its activities ! nucleus %[s itself to be entirely diff]5t f ! protoplasm4 ,x conta9s c]ta9 def9ite bodies n f\nd 9 ! cell sub/ance1 & x goes ?r\gh a s]ies ( activities :i* are entirely unrepres5t$ 9 ! surr\nd+ protoplasm4 ,x is some?+ entirely di/9ct1 & its relations to ! life ( ! cell are unique & m>vel\s4 ,^! v>i\s facts l$ to a p]iod 9 ! discussion ( biological topics :i* may n inappropriately be call$ ! ,reign ( ! ,nucleus4 ,let u1 !re=e1 see :at ?is /ructure is :i* has dem&$ s mu* att5tion 9 ! la/ tw5ty ye>s4 7b7 ,/ructure ( ! ,nucleus4--,at fir/ ! nucleus appe>s to be v mu* l ! cell sub/ance4 ,l ! latt]1 x is made ( fibres1 :i* =m a reticulum 7,fig4 #bc71 & ^! fibres1 l ^? ( protoplasm1 h microsomes 9 intimate relation ) !m & hold a cle> liquid 9 _! me%es4 ,! me%es ( ! network are usually r clos] ?an 9 ! out] cell sub/ance1 b _! g5]al "* appe>s to be ! same4 ,b a m close /udy ( ! nucleus discloses va/ diff]5ces4 ,9 ! fir/ place1 ! nucleus is usually sep>at$ f ! cell sub/ance by a membrane 7,fig4 #bc1 c74 ,?is membrane is almo/ always pres5t1 b x may disappe>1 & usually does disappe>1 :5 ! nucleus beg9s to divide4 ,)9 ! nucleus we f9d commonly "o or two small] bodies1 ! nucleoli 7,fig4 #bc1 f74 ,!y appe> to be di/9ct vital p>ts ( ! nucleus1 & ?us diff]5t f c]ta9 o!r solid bodies :i* are simply excret$ mat]ial1 & h5ce lifeless4 ,fur!r1 we f9d t ! reticulum )9 ! nucleus is made up ( two v diff]5t p>ts4 ,"o portion is app>5tly id5tical ) ! reticulum ( ! cell sub/ance 7,fig4 #bc1 d74 ,?is =ms an extremely delicate network1 ^: fibres h *emical relations simil> to ^? ( ! cell sub/ance4 ,inde$1 sometimes1 ! fibres ( ! nucleus may be se5 to pass directly into ^? ( ! network ( ! cell sub/ance1 & h5ce !y are 9 all probability id5tical4 ,?is mat]ial is call$ l991 by :i* "n we %all h]eaft] ref] to x4 ,!re is1 h[ev]1 9 ! nucleus ano!r mat]ial :i* =ms ei!r ?reads1 or a network1 or a mass ( granules1 :i* is v diff]5t f ! l991 & has entirely diff]5t prop]ties4 ,?is network has ! p[] ( absorb+ c]ta9 k9ds ( /a9s v actively1 & is consequ5tly deeply /a9$ :5 treat$ z ! microscopi/ commonly prep>es 8 specim5s4 ,= ?is reason x has be5 nam$ *romat9 7,fig1 #bc1 e71 al?\gh 9 m rec5t times o!r names h be5 giv5 to x4 ,( all p>ts ( ! cell ?is *romat9 is ! mo/ rem>kable4 ,x appe>s 9 great v>iety 9 diff]5t cells1 b x always has rem>kable physiological prop]ties1 z w be notic$ pres5tly4 ,all ?+s consid]$1 ?is *romat9 is probably ! mo/ rem>kable body connect$ ) organic life4 ,illu/ration3 ,,fig4 #bf4--;,diff]5t =ms ( nucleii4 ,! nucleii ( diff]5t animals & plants all %[ ess5tially ! *>act]i/ics j describ$4 ,!y all conta9 a liquid1 a l99 network1 & a *romat9 ?read or network1 b !y diff] mo/ rem>kably 9 details1 s t ! v>iety among ! nucleii is almo/ endless 7,fig4 #bf74 ,!y diff] fir/ 9 _! size relative to ! size ( ! cell2 sometimes--especially 9 "y cells--! nucleus be+ v l>ge1 :ile 9 o!r cases ! nucleus is v small & ! protoplasmic cont5ts ( ! cell v l>ge2 f9ally1 9 cells :i* h lo/ _! activity ! nucleus may almo/ or entirely disappe>4 ,!y diff]1 secondly1 9 %ape4 ,! typical =m appe>s to be sph]ical or ne>ly s2 b f ?is typical =m !y may v>y1 becom+ irregul> or elongat$4 ,!y are sometimes drawn out into long masses look+ l a /r+ ( beads 7,fig4 #bd71 or1 aga91 resembl+ m9ute coil$ worms 7,fig4 #ba71 :ile 9 /ill o!r cells !y may be bran*+ l ! twigs ( a tree4 ,! =m & %ape ( ! *romat9 ?read diff]s widely4 ,sometimes ?is appe>s to be m]e reticulum 7,fig4 #bc72 at o!rs1 a %ort ?read :i* is some:at twi/$ or coil$ 7,fig4 #bf72 :ile 9 o!r cells ! *romat9 ?read is an extremely long1 v mu* twi/$ convolute ?read s complexly wov5 into a tangle z to give ! appe>ance ( a m9ute network4 ,! nucleii diff] also 9 ! numb] ( nucleoli !y conta9 z well z 9 o!r less important p>ticul>s4 ,fig4 #bf w give a little notion ( ! v>iety to be f\nd among diff]5t nucleii2 b al?\gh !y ?us d v>y mo/ rem>kably 9 %ape 9 ! ess5tial p>ts ( _! /ructure !y are alike4 ,c5trosome4--,be=e notic+ ! activities ( ! nucleus x w be necess>y to m5tion a ?ird "p ( ! cell4 ,)9 ! la/ few ye>s !re has be5 f\nd to be pres5t 9 mo/ cells an organ :i* has be5 call$ ! c5trosome4 ,?is body is %[n at ,fig4 #bc1 g4 ,x is f\nd 9 ! cell sub/ance j outside ! nucleus1 & commonly appe>s z an extremely m9ute r\nd$ dot1 s m9ute t no int]nal /ructure has be5 disc]n$4 ,x may be no l>g] ?an ! m9ute granules or microsomes 9 ! cell1 & until rec5tly x entirely escap$ ! notice ( microscopi/s4 ,x has n[1 h[ev]1 be5 cle>ly demon/rat$ z an active "p ( ! cell & entirely di/9ct f ! ord9>y microsomes4 ,x /a9s diff]5tly1 &1 z we %all soon see1 x appe>s to be 9 mo/ intimate connection ) ! c5t] ( cell life4 ,9 ! activities :i* *>act]ize cell life ?is c5trosome appe>s to lead ! way4 ,f x radiate ! =ces :i* control cell activity1 & h5ce ?is c5trosome is sometimes call$ ! dynamic c5t] ( ! cell4 ,?is leads u to ! /udy ( cell activity1 :i* discloses to u "s ( ! mo/ extraord9>y ph5om5a :i* h come to ! k ( sci5ce4 ,function ( ! ,nucleus4--,to und]/& :y x is t ! nucleus has tak5 su* a prom95t position 9 mod]n biological discussion x w be only necess>y to notice "s ( ! activities ( ! cell4 ,( ! f\r fundam5tal vital prop]ties ( cell life ! "o :i* has be5 mo/ /udi$ & 9 reg>d to :i* mo/ is kn[n is reproduction4 ,?is k appe>s *iefly "u two heads1 viz41 cell division & ! f]tilization ( ! egg4 ,e animal & plant beg9s its life z a simple cell1 & ! gr[? ( ! cell into ! adult is simply ! division ( ! orig9al cell into p>ts accompani$ by a diff]5tiation ( ! p>ts4 ,! fundam5tal ph5om5a ( gr[? & reproduction is ?us cell division1 & if we c compreh5d ?is process 9 ^! simple cells we %all c]ta9ly h tak5 a great /ep t[>d ! explanation ( ! me*anics ( life4 ,dur+ ! la/ t5 ye>s ?is cell division has be5 mo/ ?or\ghly /udi$1 & we h a pretty good k ( x s f> z its microscopical features are conc]n$4 ,! foll[+ description w outl9e ! g5]al facts ( su* cell division1 & w apply ) consid]able accuracy to all cases ( cell division1 al?\gh ! details may diff] n a little4 ,illu/ration3 ,,fig4 #bg4--,?is & ! foll[+ figures %[ /ages 9 cell division4 ,fig4 #bg %[s ! re/+ /age ) ! *romat91 cr1 9 ! =m ( a network )9 ! nucle> membrane & ! c5trosome1 ce1 already divid$ into two4 ,illu/ration3 ,,fig4 #bh4--,! *romat9 is brok5 into ?reads or *romosomes1 cr4 ,! c5trosomes %[ radiat+ fibres4 ,cell ,division or ,k>yok9esis4--,we w beg9 ) a cell 9 :at is call$ ! re/+ /age1 %[n at ,fig4 #bc4 ,su* a cell has a nucleus1 ) its *romat91 its membrane1 & l991 z already describ$4 ,outside ! nucleus is ! c5trosome1 or1 m commonly1 two ( !m ly+ close toge!r4 ,if !re is only "o x soon divides into two1 & if x has already two1 ?is is because a s+le c5trosome :i* ! cell orig9ally possess$ has already divid$ into two1 z we %all pres5tly see4 ,?is cell1 9 %ort1 is precisely l ! typical cell :i* we h describ$1 except 9 ! possession ( two c5trosomes4 ,! fir/ indication ( ! cell division is %[n by ! *romat9 fibres4 ,dur+ ! re/+ /age ?is *romat9 mat]ial may h ! =m ( a ?read1 or may =m a network ( fibres 7see ,fig4 #bg74 ,b :atev] be its =m dur+ ! re/+ /age1 x assumes ! =m ( a ?read z ! cell prep>es = division4 ,almo/ at once ?is ?read breaks into a numb] ( pieces kn[n z *romosomes 7,fig4 #bh74 ,x is an extremely important fact t ! numb] ( ^! *romosomes 9 ! ord9>y cells ( any animal or plant is always ! same4 ,9 o!r words1 9 all ! cells ( ! body ( animal or plant ! *romat9 mat]ial 9 ! nucleus breaks into ! same numb] ( %ort ?reads at ! "t t ! cell is prep>+ to divide4 ,! numb] is ! same = all animals ( ! same species1 & is nev] dep>t$ f4 ,= example1 ! numb] 9 ! ox is always sixte51 :ile ! numb] 9 ! lily is always tw5ty-f\r4 ,dur+ ?is process ( ! =mation ( ! *romosomes ! nucleoli disappe>1 sometimes be+ absorb$ app>5tly 9 ! *romosomes1 & sometimes be+ eject$ into ! cell body1 :]e !y disappe>4 ,:e!r !y h any?+ to d ) fur!r *anges is n yet kn[n4 ,! next /ep 9 ! process ( division appe>s 9 ! region ( ! c5trosomes4 ,ea* ( ! two c5trosomes appe>s to s5d out f itself delicate radiat+ fibres into ! surr\nd+ cell sub/ance 7,fig4 #bh74 ,:e!r ^! actually arise f ! c5trosome or are simply a re>rangem5t ( ! fibres 9 ! cell sub/ance is n cle>1 b at all ev5ts ! c5trosome becomes surr\nd$ by a mass ( radiat+ fibres :i* give x a />like appe>ance1 or1 m commonly1 ! appe>ance ( a d\ble />1 s9ce !re are two c5trosomes close toge!r 7,fig4 #bh74 ,^! radiat+ fibres1 :e!r aris+ f ! c5trosomes or n1 c]ta9ly all c5tre 9 ^! bodies1 a fact :i* indicates t ! c5trosomes conta9 ! =ces :i* regulate _! appe>ance4 ,betwe5 ! two />s or a/]s a set ( fibres c be se5 runn+ f "o to ! o!r 7,fig4 #bi74 ,^! two a/]s & ! c5trosomes )9 !m h be5 spok5 ( z ! dynamic c5tre ( ! cell s9ce !y appe> to control ! =ces :i* lead to cell division4 ,9 all ! *anges :i* foll[ ^! a/]s lead ! way4 ,! two a/]s1 ) _! c5trosomes1 n[ move away f ea* o!r1 always connect$ by ! sp9dle fibres1 & f9ally come to lie on opposite sides ( ! nucleus 7,figs4 #bi1 #cj74 ,:5 !y rea* ?is position !y are /ill surr\nd$ by ! radiat+ fibres1 & connect$ by ! sp9dle fibres4 ,meantime ! membrane ar\nd ! nucleus has disappe>$1 & ?us ! sp9dle fibres readily p5etrate into ! nucle> sub/ance 7,fig4 #cj74 ,illu/ration3 ,,fig4 #bi4--,! c5trosomes are sep>at+ b are connect$ by fibres4 ,illu/ration3 ,,fig4 #cj4--,! c5trosomes are sep>ate & ! equatorial plate ( *romosomes1 cr1 is betwe5 !m4 ,dur+ ?is "t ! *romosomes h be5 *ang+ _! position4 ,:e!r ?is *ange 9 position is due to =ces )9 !mselves1 or :e!r !y are mov$ ar\nd passively by =ces resid+ 9 ! cell sub/ances1 or :e!r1 :i* is ! mo/ probable1 !y are pull$ or pu%$ ar\nd by ! sp9dle fibres :i* are =c+ _! way into ! nucleus1 is n positively kn[n2 nor is x1 = our purposes1 ( special importance4 ,at all ev5ts1 ! result is t :5 ! a/]s h assum$ _! position at opposite poles ( ! nucleus ! *romosomes are arrang$ 9 a plane pass+ ?r\gh ! middle ( ! nucleus at equal di/ances f ea* a/]4 ,x seems c]ta9 t !y are pull$ or pu%$ into ?is position by =ces radiat+ f ! c5trosomes4 ,fig4 #cj %[s ?is c5tral arrangem5t ( ! *romosomes1 =m+ :at is call$ ! equatorial plate4 ,! next /ep is ! mo/ significant ( all4 ,x consi/s 9 ! splitt+ ( ea* *romosome into two equal halves4 ,! ?reads d n divide 9 _! middle b split l5g?wise1 s t !re are =m$ two halves id5tical 9 e respect4 ,9 ?is way are produc$ twice ! orig9al numb] ( *romosomes1 b all 9 pairs4 ,! p]iod at :i* ?is splitt+ ( ! *romosomes occurs is n ! same 9 all cells4 ,x may occur1 z describ$1 at ab\t ! "t ! a/]s h rea*$ ! opposite poles ( ! nucleus1 & an equatorial plate is =m$4 ,x is n infrequ5t1 h[ev]1 = x to occur at a p]iod consid]ably e>li]1 s t ! *romosomes are already divid$ :5 !y are br\ght into ! equatorial plate4 ,at "s p]iod or o!r 9 ! cell division ?is splitt+ ( ! *romosomes takes place4 ,! significance ( ! splitt+ is especially notewor?y4 ,we %all soon f9d reason = believ+ t ! *romosomes conta9 all ! h]$it>y traits :i* ! cell h&s d[n f g5]ation to g5]ation1 & inde$ t ! *romosomes ( ! egg conta9 all ! traits :i* ! p>5t h&s d[n to ! *ild4 ,n[1 if ?is *romat9 ?read consi/s ( a s]ies ( units1 ea* repres5t+ c]ta9 h]$it>y *>act]s1 !n x is pla9 t ! division ( ! ?read by splitt+ w give rise to a d\ble s]ies ( ?reads1 ea* ( :i* has id5tical *>act]s4 ,%\ld ! division occur across ! ?read ! two halves w\ld be unlike1 b tak+ place z x does by a longitud9al splitt+ ea* unit 9 ! ?read simply divides 9 half1 & ?us ! result+ half ?reads ea* conta9 ! same numb] ( simil> units z ! o!r & ! same z possess$ by ! orig9al undivid$ *romosome4 ,?is sort ( splitt+ ?us d\bles ! numb] ( *romosomes1 b produces no diff]5tiation ( mat]ial4 ,illu/ration3 ,,fig4 #ca4--,/age %[+ ! two halves ( ! *romosomes sep>at$ f ea* o!r4 ,illu/ration3 ,,fig4 #cb4--;,f9al /age ) two nucleii 9 :i* ! *romosomes h aga9 assum$ ! =m ( a network4 ,! c5trosomes h divid$ prep>atory to ! next division1 & ! cell is beg9n+ to divide4 ,! next /ep 9 ! cell division consi/s 9 ! sep>ation ( ! two halves ( ! *romosomes4 ,ea* half ( ea* *romosome sep>ates f its fell[1 & moves to ! opposite end ( ! nucleus t[>d ! two c5trosomes 7,fig4 #ca74 ,:e!r !y are pull$ ap>t or pu%$ ap>t by ! sp9dle fibres is n c]ta91 al?\gh x is app>5tly sure t ^! fibres f ! c5trosomes are engag$ 9 ! matt]4 ,c]ta9 x is t "s =ce ex]t$ f ! two c5trosomes acts ^u ! *romosomes1 & =ces ! two halves ( ea* "o to opposite ends ( ! nucleus1 :]e !y n[ collect & =m two new nucleii1 ) evid5tly exactly ! same numb] ( *romosomes z ! orig9al1 & ) *>act]s id5tical to ea* o!r & to ! orig9al 7,fig4 #cb74 ,! re/ ( ! cell division n[ foll[s rapidly4 ,a p>tition gr[s 9 ?r\gh ! cell body divid+ x into two p>ts 7,fig4 #cb71 ! division pass+ ?r\gh ! middle ( ! sp9dle4 ,9 ?is division1 9 "s cases at lea/1 ! sp9dle fibres be> a "p--a fact :i* aga9 po9ts to ! importance ( ! c5trosomes & ! =ces :i* radiate f !m4 ,n[ ! *romosomes 9 ea* daught] nucleus unite to =m a s+le ?read1 or may diffuse ?r\gh ! nucleus to =m a network1 z 9 ,fig4 #cb4 ,!y n[ become surr\nd$ by a membrane1 s t ! new nucleus appe>s exactly l ! orig9al "o4 ,! sp9dle fibres disappe>1 & ! a/ral fibres may ei!r disappe> or rema9 visible4 ,! c5trosome may app>5tly 9 "s cases disappe>1 b m commonly rema9s beside ! daught] nucleii1 or x may move into ! nucleus4 ,ev5tually x divides into two1 ! division commonly occurr+ at once 7,fig4 #cb71 b sometimes n until ! next cell division is ab\t to beg94 ,?us ! f9al result %[s two cells ea* ) a nucleus & two c5trosomes1 & ?is is exactly ! same sort ( /ructure ) :i* ! process began4 7,see ,frontispiece47 ,view$ z a :ole1 we may make ! foll[+ g5]al summ>y ( ?is process4 ,! ess5tial object ( ?is complicat$ ph5om5a ( k>yok9esis is to divide ! *romat9 into equival5t halves1 s t ! cells result+ f ! cell division %all conta9 an exactly equival5t *romat9 cont5t4 ,= ?is purpose ! *romatic elem5ts collect into ?reads & split l5g?wise4 ,! c5trosome1 ) its fibres1 br+s ab\t ! sep>ation ( ^! two halves4 ,pla9ly1 we mu/ conclude t ! *romat9 mat]ial is some?+ ( extraord9>y importance to ! cell1 & ! c5trosome is a bit ( ma*9]y = controll+ its division & ?us regulat+ cell division4 ,f]tilization ( ! ,egg4--,?is description ( cell division w c]ta9ly give "s idea ( ! complexity ( cell life1 b a m m>vel\s s]ies ( *anges /ill takes place dur+ ! "t :5 ! egg is prep>+ = developm5t4 ,inasmu* z ?is process /ill fur!r illu/rates ! nature ( ! cell1 & has fur!r a mo/ intimate be>+ ^u ! fundam5tal problem ( h]$ity1 x w be necess>y = u to consid] x "h briefly4 ,! sexual reproduction ( ! _m-cell$ animals is always ess5tially alike4 ,a s+le "o ( ! body cells is set ap>t to />t ! next g5]ation1 & ?is cell1 aft] sep>at+ f ! body ( ! animal or plant :i* produc$ x1 beg9s to divide1 z already %[n 9 ,fig4 #h1 & ! _m cells :i* arise f x ev5tually =m ! new individual ,?is reproductive cell is ! egg4 ,b be=e its division c beg9 !re occurs 9 all cases ( sexual reproduction a process call$ f]tilization1 ! ess5tial feature ( :i* is ! union ( ?is cell ) ano!r commonly f a diff]5t individual4 ,:ile ! ph5om5on is subject to consid]able diff]5ce 9 details1 x is ess5tially z foll[s3 ,illu/ration3 ,,fig4 #cc--;,an egg %[+ ! cell sub/ance & ! nucleus1 ! latt] conta9+ *romosomes 9 l>ge numb] & a nucleolus ,! female reproductive cell is call$ ! egg1 & x is ?is cell :i* divides to =m ! next g5]ation4 ,su* a cell is %[n 9 ,fig4 #cc4 ,l o!r cells x has a cell wall1 a cell sub/ance ) its l99 & fluid portions1 a nucleus surr\nd$ by a membrane & conta9+ a reticulum1 a nucleolus & *romatic mat]ial1 & la/ly1 a c5trosome4 ,n[ su* an egg is a complete cell1 b x is n able to beg9 ! process ( division :i* %all give rise to a new individual until x has unit$ ) ano!r cell ( q a diff]5t sort & commonly d]iv$ f a diff]5t individual call$ ! male4 ,:y ! egg cell is unable to develop )\t su* union ) male cell does n conc]n u "h1 b its purpose w be evid5t z ! description proce$s4 ,! egg cell z x comes f ! ov>y ( ! female individual is1 h[ev]1 n yet ready = union ) ! male cell1 b mu/ fir/ g ?r\gh a s]ies ( some:at rem>kable *anges con/itut+ :at is call$ maturation ( ! egg4 ,?is ph5om5on has su* an intimate relation to all problems connect$ ) ! cell1 t x mu/ be describ$ some:at 9 detail4 ,!re are consid]able diff]5ces 9 ! details ( ! process z x occurs 9 v>i\s animals1 b !y all agree 9 ! fundam5tal po9ts4 ,! foll[+ is a g5]al description ( ! process d]iv$ f ! /udy ( a l>ge v>iety ( animals & plants4 ,illu/ration ,fig4 #cd4--,?is & ! foll[+ figures repres5t ! process ( f]tilization ( an egg4 ,9 all figures cr is ! *romosomes2 cs repres5ts ! cell sub/ance 7omitt$ 9 ! foll[+ figures72 mc is ! male reproductive cell ly+ 9 contact ) ! egg2 mn is ! male nucleus aft] ent]+ ! egg4 ,illu/ration3 ,,fig4 #ce4--,! egg c5trosome has divid$1 & ! male cell ) its c5trosome has ent]$ ! egg4 ,9 ! cells ( ! body ( ! animal to :i* ?is description applies !re are f\r *romosomes ,?is is true ( all ! cells ( ! animal except ! sexual cells4 ,! eggs arise f ! o!r cells ( ! body1 b dur+ _! gr[? ! *romat9 splits 9 su* a way t ! egg conta9s d\ble ! numb] ( *romosomes1 i4e41 eight 7,fig4 #cd74 ,if ?is egg %\ld n[ unite ) ! o!r reproductive cell f ! male1 ! result+ f]tiliz$ egg w\ld pla9ly conta9 a numb] ( *romosomes l>g] ?an t normal = ?is species ( animal4 ,z a result ! next g5]ation w\ld h a l>g] numb] ( *romosomes 9 ea* cell ?an ! la/ g5]ation1 s9ce ! division ( ! egg 9 developm5t is l t already describ$ & always results 9 produc+ new cells ) ! same numb] ( *romosomes z ! />t+ cell4 ,h5ce1 if ! numb] ( *romosomes 9 ! next g5]ation is to be kept equal to t 9 ! la/ g5]ation1 ?is egg cell mu/ get rid ( a "p ( its *romat9 mat]ial4 ,?is is done by a process %[n 9 ,fig4 #ce4 ,! c5trosome divides z 9 ord9>y cell division 7,fig4 #ce71 & aft] rotat+ on its axis x approa*es ! surface ( ! egg 7,figs4 #cf & #cg74 ,! egg n[ divides 7,fig4 #ch71 b ! division is ( a peculi> k9d4 ,al?\gh ! *romosomes divide equally ! egg itself divides into two v unequal p>ts1 "o "p /ill appe>+ z ! egg & ! o!r z a m9ute protub]ance call$ ! pol> cell 7pc' 9 ,fig4 #ch74 ,! *romosomes d n split z !y d 9 ! cell division already describ$1 b ea* ( ^! two cells1 ! egg & ! pol> body1 receives f\r *romosomes 7,fig4 #ch74 ,! result is t ! egg has n[ ! normal numb] ( *romosomes = ! ord9>y cells ( ! animal 9 "q4 ,b ?is is /ill too _m1 = ! egg is soon to unite ) ! male cell2 & ?is male cell1 z we %all see1 is to br+ 9 its own quota ( *romosomes4 ,h5ce ! egg mu/ get rid ( /ill m ( its *romat9 mat]ial4 ,consequ5tly1 ! fir/ division is foll[$ by a second 7,fig4 #ci71 9 :i* !re is aga9 produc$ a l>ge & a small cell4 ,?is division1 l ! fir/1 occurs )\t any splitt+ ( ! *romosomes1 "o half ( ! rema9+ *romosomes be+ eject$ 9 ?is new cell1 ! second pol> cell 7pc7 leav+ ! l>g] cell1 ! egg1 ) j "o half ! numb] ( *romosomes normal = ! cells ( ! animal 9 "q4 ,meantime ! fir/ pole cell has also divid$1 s t we h n[1 z %[n 9 ,fig4 #dj1 f\r cells1 ?ree small & "o l>ge1 b ea* conta9+ "o half ! normal numb] ( *romosomes4 ,9 ! example figur$1 f\r is ! normal numb] = ! cells ( ! animal4 ,! egg at ! beg9n+ ( ! process conta9$ eight1 b has n[ be5 r$uc$ to two4 ,9 ! fur!r hi/ory ( ! egg ! small] cells1 call$ pol> cells1 take no "p1 s9ce !y soon disappe> & h no?+ to d ) ! animal :i* is to result f ! fur!r division ( ! egg4 ,?is process ( ! =mation ( ! pol> cells is ?us simply a device = gett+ rid ( "s ( ! *romat9 mat]ial 9 ! egg cell1 s t x may unite ) a second cell )\t d\bl+ ! normal numb] ( *romosomes4 ,illu/ration3 ,,fig4 #ch--;,fir/ division complete & fir/ pol> cell =m$1 pc'4 ,illu/ration3 ,,fig4 #ci4--;,=mation ( ! second pol> cell1 pc4 ,illu/ration3 ,,fig4 #dj4--;,completion ( ! process ( extrusion ( ! *romatic mat]ial2 fn %[s ! two *romosomes reta9$ 9 ! egg =m+ ! female pronucleus4 ,! c5trosome has disappe>$4 ,previ\sly to ?is process ! o!r sexual cell1 ! sp]matozoon1 or male reproductive cell1 has be5 und]go+ a some:at simil> process4 ,?is is also a true cell 7,fig4 #cd1 mc71 al?\gh x is ( a decid$ly small] size ?an ! egg & ( a v diff]5t %ape4 ,x conta9s cell sub/ance1 a nucleus ) *romosomes1 & a c5trosome1 ! numb] ( *romosomes1 z %[n lat]1 be+ h[ev] only half t normal = ! ord9>y cells ( ! animals4 ,! /udy ( ! developm5t ( ! sp]matozoon %[s t x has come f cells :i* conta9$ ! normal numb] ( f\r1 b t ?is numb] has be5 r$uc$ to "o half by a process :i* is equival5t to t :i* we h j notic$ 9 ! egg4 ,?us x comes ab\t t ea* ( ! sexual elem5ts1 ! egg & ! sp]matozoon1 n[ conta9s "o half ! normal numb] ( *romosomes4 ,illu/ration3 ,,fig4 #cf--,! egg c5trosomes h *ang$ _! position4 ,! male cell ) its c5trosome rema9s inactive until ! /age repres5t$ 9 ,fig4 #db4 ,illu/ration3 ,,fig4 #cg--;,beg9n+ ( ! fir/ division = remov+ sup]flu\s *romosomes4 ,n[ by "s me*anical means ^! two reproductive cells are br\ght 9 contact ) ea* o!r1 %[n 9 ,fig4 #cd1 & z soon z !y are br\ght into ea* o!r's vic9ity ! male cell buries its head 9 ! body ( ! egg4 ,! tail by :i* x has be5 mov+ is ca/ (f1 & ! head conta9+ ! *romosomes & ! c5trosome ent]s ! egg1 =m+ :at is call$ ! male pronucleus 7,figs4 #ce-ch1 mn74 ,?is entrance ( ! male cell occurs ei!r be=e ! =mation ( ! pol> cells ( ! egg or aft]w>d4 ,if1 h[ev]1 x takes place be=e1 ! male pronucleus simply rema9s dormant 9 ! egg :ile ! pol> cells are be+ protrud$1 & n until aft] t process is conclud$ does x beg9 aga9 to %[ signs ( activity :i* result 9 ! cell union4 ,! fur!r /eps 9 ?is process appe> to be controll$ by ! c5trosome1 al?\gh x is n q c]ta9 :5ce ?is c5trosome is d]iv$4 ,orig9ally1 z we h se51 ! egg conta9$ a c5trosome1 & ! male cell has also br\ght a second into ! egg 7,fig4 #ce1 ce74 ,9 "s cases1 & ?is is true = ! worm we are describ+1 x is c]ta9 t ! egg c5trosome disappe>s :ile t ( ! sp]matozoon is reta9$ alone to direct ! fur!r activities 7,fig4 #da74 ,possibly ?is may be ! case 9 all eggs1 b x is n sure4 ,x is a matt] ( "s little int]e/ to h ?is settl$1 = if x %\ld prove true1 !n x w\ld evid5tly foll[ t ! ma*9]y = cell division1 9 ! case ( sexual reproduction1 is d]iv$ f ! fa!r1 al?\gh ! bulk ( ! cell comes f ! "m1 :ile ! *romosomes come f bo? p>5ts4 ,9 ! cases :]e ! process has be5 mo/ c>efully /udi$1 ! fur!r *anges are z foll[s3 ,! head ( ! sp]matozoon1 aft] entrance into ! egg1 lies dormant until ! egg has ?r[n (f its pol> cells1 & ?us gott5 rid ( "p ( its *romosomes4 ,close to x lies its c5trosomes 7,fig4 #ce1 ce71 & !re is ?us =m$ :at is kn[n z ! male pronucleus 7,fig4 #ce-dj1 mn74 ,! rema9s ( ! egg nucleus1 aft] hav+ dis*>g$ ! pol> cells1 =m ! female nucleus 7,fig4 #dj1 fn74 ,! *romat9 mat]ial1 9 bo? ! male & female pronucleus1 soon breaks up into a network 9 :i* x is no long] possible to see t ea* conta9s two *romosomes 7,fig4 #da74 ,n[ ! c5trosome1 :i* is beside ! male pronucleus1 %[s signs ( activity4 ,x becomes surr\nd$ by prom95t rays to =m an a/] 7,fig4 #da1 ce71 & !n x beg9s to move t[>d ! female pronucleus1 app>5tly dragg+ ! male pronucleus aft] x4 ,9 ?is way ! c5trosome approa*es ! female pronucleus1 & ?us f9ally ! two nucleii are br\ght into close proximity4 ,meantime ! *romat9 mat]ial 9 ea* has once m brok5 up into %ort ?reads or *romosomes1 & once m we f9d t ea* ( ! nucleii conta9s two ( ^! bodies 7,fig4 #db74 ,9 ! subsequ5t figures ! *romosomes ( ! male nucleus are lightly %ad$1 :ile ^? ( ! female are black 9 ord] to di/+ui% !m4 ,z ^! two nucleii f9ally come toge!r _! membranes disappe>1 & ! *romatic mat]ial comes to lie freely 9 ! egg1 ! male & female *romosomes1 side by side1 b di/9ct =m+ ! segm5tation nucleus4 ,! egg pla9ly n[ conta9s once m ! numb] ( *romosomes normal = ! cells ( ! animal1 b half ( !m h be5 d]iv$ f ea* p>5t4 ,x is v sugge/ive to f9d fur!r t ! *romosomes 9 ?is f]tiliz$ egg d n fuse ) ea* o!r1 b rema9 q di/9ct1 s t x c be se5 t ! new nucleus conta9s *romosomes d]iv$ f ea* p>5t 7,fig4 #db74 ,nor does !re appe> to be1 9 ! future hi/ory ( ?is egg1 any actual fusion ( ! *romatic mat]ial1 ! male & female *romosomes p]haps always rema9+ di/9ct4 ,illu/ration3 ,,fig4 #da4--,! *romosomes 9 ! male & female pronucleii h resolv$ into a network4 ,! male c5trosome beg9s to %[ signs ( activity4 ,illu/ration3 ,,fig4 #db4--,! c5trosome has divid$1 & ! two pronucleii h be5 br\ght toge!r4 ,! network 9 ea* nucleus has aga9 resolv$ itself into two *romosomes :i* are n[ br\ght toge!r ne> ! c5tre ( ! egg b d n fuse2 mcr1 repres5ts ! *romosomes f ! male nucleus2 fcr1 ! *romosomes f ! female nucleus4 ,illu/ration3 ,,fig4 #dc4--;,an equatorial plate is =m$ & ea* *romosome has split into two halves by longitud9al division4 ,illu/ration3 ,,fig4 #dd4--,! halves ( ! *romosomes h sep>at$ to =m two nucleii1 ea* ) male & female *romosomes4 ,! egg has divid$ into two cells4 ,:ile ?is mixture ( *romosomes has be5 tak+ place ! c5trosome has divid$ into two p>ts1 ea* ( :i* becomes surr\nd$ by an a/] & travels to opposite ends ( ! nucleus 7,fig4 #db74 ,!re n[ foll[s a division ( ! nucleus exactly simil> to t :i* occurs 9 ! normal cell division already describ$ 9 ,figs4 #bh-cd4 ,ea* ( ! *romosomes splits l5g?wise 7,fig4 #dc71 & "o half ( ea* !n travels t[>d ea* c5trosome to =m a new nucleus 7,fig4 #dd74 ,s9ce ea* ( ! f\r *romosomes ?us splits1 x foll[s t ea* ( ! two daught] nucleii w1 ( c\rse1 conta9 f\r *romosomes2 two ( :i* h be5 d]iv$ f ! male & two f ! female p>5t4 ,f n[ ! divisions ( ! egg foll[ rapidly by ! normal process ( cell division until f ?is "o egg cell !re are ev5tually d]iv$ hundr$s ( ?\s&s ( cells :i* are gradually m\ld$ into ! adult4 ,all ( ^! cells w1 ( c\rse1 conta9 f\r *romosomes2 &1 :at is m important1 half ( ! *romosomes w h be5 d]iv$ directly f ! male & half f ! female p>5t4 ,ev5 into adult life1 !re=e1 ! cells ( ! animal probably conta9 *romat9 d]iv$ by direct desc5t f ea* ( its p>5ts4 ,! ,significance ( ,f]tilization4--,f ?is process ( f]tilization a numb] ( conclusions1 highly important = our purpose1 c be drawn4 ,9 ! fir/ place1 x is evid5t t ! *romosomes =m ! "p ( ! cell :i* conta9 ! h]$it>y traits h&$ d[n f p>5t to *ild4 ,?is foll[s f ! fact t ! *romosomes are ! only "p ( ! cell :i*1 9 ! f]tiliz$ egg1 is d]iv$ f bo? p>5ts4 ,n[ ! (fspr+ c c]ta9ly inh]it f ea* p>5t1 & h5ce ! h]$it>y traits mu/ be associat$ ) "s "p ( ! cell :i* is d]iv$ f bo?4 ,b ! egg sub/ance is d]iv$ f ! "m alone2 ! c5trosome1 at lea/ 9 "s cases & p]haps 9 all1 is d]iv$ only f ! fa!r1 :ile ! *romosomes are d]iv$ f bo? p>5ts4 ,h5ce x foll[s t ! h]$it>y traits mu/ be p>ticul>ly associat$ ) ! *romosomes4 ,) ?is und]/&+ we c1 at lea/1 9 "p und]/& ! purpose ( f]tilization4 ,z we %all see lat]1 x is v necess>y 9 ! build+ ( ! liv+ ma*9e = ea* individual to inh]it *>act]s f m ?an "o individual4 ,?is is necess>y to produce ! num]\s v>iations :i* contribute to ! con/ruction ( ! ma*9e4 ,= ?is purpose !re has be5 develop$ ! process ( sexual union ( reproductive cells1 :i* introduces into ! (fspr+ *romatic mat]ial f two p>5ts4 ,b if ! two reproductive cells %\ld unite at once ! numb] ( *romosomes w\ld be d\bl$ 9 ea* g5]ation1 & h5ce be con/antly increas+4 ,to prev5t ?is ! pol> cells are ca/ out1 :i* r$uces ! am\nt ( *romatic mat]ial4 ,! union ( ! two pronucleii is pla9ly to produce a nucleus :i* %all conta9 *romosomes1 & h5ce h]$it>y traits f ea* p>5t & ! subsequ5t splitt+ ( ^! *romosomes & ! sep>ation ( ! two halves into daught] nucleii insures t all ! nucleii1 & h5ce all cells ( ! adult1 %all possess h]$it>y traits d]iv$ f bo? p>5ts4 ,?us x comes t1 ev5 9 ! adult1 e body cell is made up ( *romosomes f ea* p>5t1 & may h5ce inh]it *>act]s f ea*4 ,! cell ( an animal ?us consi/s ( ?ree some:at di/9ct b active p>ts--! cell sub/ance1 ! *romosomes1 & ! c5trosome4 ,( ^! ! cell sub/ance appe>s to be h&$ d[n f ! "m2 ! c5trosome comes1 at lea/ 9 "s cases1 f ! fa!r1 & ! *romosomes f bo? p>5ts4 ,x is n yet c]ta91 h[ev]1 :e!r ! c5trosome is a con/ant "p ( ! cell4 ,9 "s cells x _c yet be f\nd1 & !re are "s reasons = believ+ t x may be =m$ out ( o!r p>ts ( ! cell4 ,! nucleus is always a direct desc5dant f ! nucleus ( pre-exi/+ cells1 s t !re is an absolute cont9uity ( desc5t betwe5 ! nucleii ( ! cells ( an individual & ^? ( its antec$5ts back = numb]less g5]ations4 ,x is n c]ta9 t !re is any su* cont9uity ( desc5t 9 ! case ( ! c5trosomes2 =1 :ile 9 ! process ( f]tilization ! c5trosome is h&$ d[n f p>5t to *ild1 !re are "s reasons = believ+ t x may disappe> 9 subsequ5t cells1 & lat] be r$evelop$ out ( o!r p>ts4 ,! only "p ( ! cell 9 :i* complete cont9uity f p>5t to *ild is demon/rat$1 is ! nucleus & p>ticul>ly ! *romosomes4 ,all ( ^! facts simply emphasize ! importance ( ! *romosomes1 & tell u t ^! bodies mu/ be reg>d$ z conta9+ ! mo/ important features ( ! cell :i* con/itute its individuality4 ,:at is ,protoplasm8--,en\gh has n[ be5 giv5 ( disclosures ( ! mod]n microscope to %[ t our old fri5d ,protoplasm has assum$ an entirely new guise1 if inde$ x has n disappe>$ altoge!r4 ,^! simple/ life processes are s m>vel\s & involve ! action ( su* an intricate mass ( ma*9]y t we c no long] reta9 our e>li] notion ( protoplasm z ! physical basis ( life4 ,!re c be no life )\t ! prop]ties ( assimilation1 gr[?1 & reproduction2 &1 s f> z we "k1 ^! prop]ties are f\nd only 9 t comb9ation ( bodies :i* we call ! cell1 ) its mixture ( h>moni\sly act+ p>ts4 ,life1 at lea/ ! life ( a cell1 is !n n ! prop]ty ( a *emical comp\nd protoplasm1 b is ! result ( ! activities ( a ma*9e4 ,inde$1 we are n[ at a loss to "k h[ we c reta9 ! t]m protoplasm4 ,z orig9ally us$ x meant ! cont5ts ( ! cell1 & ! significance 9 ! t]m 0 9 ! conception ( protoplasm z a some:at homog5e\s *emical comp\nd uni=m 9 all types ( life4 ,b we n[ see t ?is cell conta9s n a s+le sub/ance1 b a l>ge numb]1 includ+ solids1 jelly masses1 & liquids1 ea* ( :i* has its own *emical composition4 ,! numb] ( *emical comp\nds exi/+ 9 ! mat]ial =m]ly call$ protoplasm no "o kn[s1 b we d "k t !y are _m1 & t ! diff]5t sub/ances are comb9$ to =m a physical /ructure4 ,:i* ( ^! v>i\s bodies %all we cont9ue to call protoplasm8 ,%all x be ! l991 or ! liquids1 or ! microsomes1 or ! *romat9 ?reads1 or ! c5trosomes8 ,:i* ( ^! is ! actual physical basis ( life8 ,f ! description ( cell life :i* we h giv51 x w be evid5t t no "o ( !m is a mat]ial ^u :i* our *emical biologi/s c long] f\nd a *emical !ory ( life4 ,t *emical !ory ( life1 z we h se51 0 f\nd$ ^u ! conception t ! primitive life sub/ance is a def9ite *emical comp\nd4 ,no su* comp\nd has be5 discov]$1 & ^! disclosures ( ! microscope ( ! la/ few ye>s h be5 su* z to lead u to ab&on hope ( ev] discov]+ su* a comp\nd4 ,x is app>5tly impossible to r$uce life to any simpl] basis ?an ?is comb9ation ( bodies :i* make up :at 0 =m]ly call$ protoplasm4 ,! t]m protoplasm is /ill 9 use ) diff]5t mean+s z us$ by diff]5t writ]s4 ,sometimes x is us$ to ref] to ! entire cont5ts ( ! cell2 sometimes to ! cell sub/ance only outside ! nucleus4 ,pla9ly1 x is n ! protoplasm ( e>li] ye>s4 ,) ?is conclusion "o ( our fundam5tal que/ions has be5 answ]$4 ,we f\nd 9 our fir/ *apt] t ! g5]al activities ( animals & plants are easily r$uc$ to ! action ( a ma*9e1 provid$ we _h ! fundam5tal vital p[]s resid+ 9 ! p>ts ( t ma*9e4 ,we !n ask$ :e!r ^! fundam5tal prop]ties 7 !mselves ^? ( a *emical comp\nd or :e!r !y 7 to be r$uc$ to ! action ( /ill small] ma*9es4 ,! fir/ answ] :i* biologi/s gave to ?is "q 0 t assimilation1 gr[?1 & reproduction 7 ! simple prop]ties ( a complex *emical comp\nd4 ,?is answ] 0 c]ta9ly incorrect4 ,life activities are exhibit$ by no *emical comp\nd1 b1 s f> z we "k1 only by ! ma*9e call$ ! cell4 ,?us x is t we are aga9 r$uc$ to ! problem ( und]/&+ ! action ( a ma*9e4 ,x may be well to pause "h a mom5t to notice t ?is position v greatly increases ! difficulties 9 ! way ( a solution ( ! life problem4 ,if ! physical basis ( life _h prov$ to be a *emical comp\nd1 ! problem ( its orig9 w\ld h be5 a *emical "o4 ,*emical =ces exi/ 9 nature1 & ^! =ces are suffici5t to expla9 ! =mation ( any k9d ( *emical comp\nd4 ,! problem ( ! orig9 ( ! life sub/ance w\ld !n h be5 simply to acc\nt = c]ta9 conditions :i* result$ 9 su* *emical comb9ation z w\ld give rise to ?is physical basis ( life4 ,b n[ t ! simple/ sub/ance manife/+ ! ph5om5a ( life is f\nd to be a ma*9e1 we c no long] f9d 9 *emical =ces effici5t causes = its =mation4 ,*emical =ces & *emical aff9ity c expla9 *emical comp\nds ( any degree ( complexity1 b !y _c expla9 ! =mation ( ma*9es4 ,ma*9es are ! result ( =ces ( an entirely diff]5t nature4 ,man c manufacture ma*9es by tak+ *emical comp\nds & putt+ !m toge!r into su* relations t _! int]action w give c]ta9 results4 ,bits ( iron & /eel1 = in/ance1 are put toge!r to =m a locomotive1 b ! action ( ! locomotive dep5ds1 n ^u ! *emical =ces :i* made ! /eel1 b ^u ! relation ( ! bits ( /eel to ea* o!r 9 ! ma*9e4 ,s f> z we h _h any exp]i5ce1 ma*9es h be5 built "u ! guidance ( intellig5ce :i* adapts ! p>ts to ea* o!r4 ,:5 !re=e we f9d t ! simple/ life sub/ance is a ma*9e1 we are =c$ to ask :at =ces exi/ 9 nature :i* c 9 a simil> way build ma*9es by ! adju/m5t ( p>ts to ea* o!r4 ,b ?is topic belongs to ! second "p ( our subject1 & mu/ be = ! pres5t po/pon$4 ,reaction aga9/ ! ,cell ,doctr9e4--,z ! k ( cells :i* we h outl9$ 0 sl[ly acquir$1 ! conception ( ! cell pass$ ?r\gh v>i\s modifications4 ,at fir/ ! cell wall 0 look$ ^u z ! fundam5tal "p1 b ?is idea soon gave place to ! belief t x 0 ! protoplasm t 0 alive4 ,"u ! influ5ce ( ?is ?\ght ! cell doctr9e develop$ into some?+ l ! foll[+3 ,! cell is simply a bit ( protoplasm & is ! unit ( liv+ matt]4 ,! bodies ( all l>g] animals & plants are made up ( great numb]s ( ^! units act+ toge!r1 & ! activities ( ! entire organism are simply ! sum ( ! activities ( its cells4 ,! organism is ?us simply ! sum ( ! cells :i* compose x1 & its activities ! sum ( ! activities ( ! individual cells4 ,z m facts 7 disclos$ ! idea *ang$ slightly4 ,! importance ( ! nucleus became m & m =cibly impress$ ^u microscopi/s1 & ?is body came aft] a little into su* prom95ce z to hide f view ! m famili> protoplasm4 ,! m>vell\s activities ( ! nucleus soon caus$ x to be reg>d$ z ! important "p ( ! cell1 :ile all ! re/ 0 second>y4 ,! cell 0 n[ ?\ght ( z a bit ( nucle> matt] surr\nd$ by second>y p>ts4 ,! m>vell\s activities ( ! nucleus1 & above all1 ! fact t ! nucleus alone is h&$ d[n f "o g5]ation to ! next 9 reproduction1 all atte/$ to its great importance & to ! second>y importance ( ! re/ ( ! cell4 ,?is 0 ! mo/ extreme position ( ! cell doctr9e4 ,! cell 0 ! unit ( liv+ action1 & ! high] animal or plant simply a colony ( su* units4 ,an animal 0 simply an association toge!r = mutual advantage ( indep5d5t units1 j z a city is an association ( indep5d5t individuals4 ,! organization ( ! animals 0 simply ! result ( ! comb9ation ( _m indep5d5t units4 ,!re 0 no activity ( ! organism z a :ole1 b only ( its indep5d5t p>ts4 ,cell life 0 sup]ior to organiz$ life4 ,j z1 9 a city1 ! city gov]nm5t is a "n giv5 to ! comb9$ action ( ! individuals1 s are ! actions ( organisms simply ! comb9$ action ( _! individual cells4 ,aga9/ su* an extreme position !re has be5 9 rec5t ye>s a decid$ reaction1 & to-day x is becom+ m & m evid5t t su* a position _c be ma9ta9$4 ,9 ! fir/ place1 x is becom+ evid5t t ! cell sub/ance is n to be entirely oblit]at$ by ! importance ( ! nucleus4 ,t ! nucleus is a mo/ important vital c5tre is cle> en\gh1 b x is equally cle> t nucleus & cell sub/ance mu/ be toge!r to con/itute ! life sub/ance4 ,! complicat$ /ructure ( ! cell sub/ance1 ! decid$ activity %[n by its fibres 9 ! process ( cell division1 cle>ly en\gh indicate t x is a "p ( ! cell :i* c n be neglect$ 9 ! /udy ( ! life sub/ance4 ,aga9 ! discov]y ( ! c5trosome z a di/9ct morphological elem5t has /ill fur!r add$ to ! complexity ( ! life sub/ance1 & prov$ t nei!r nucleus nor cell sub/ance c be reg>d$ z ! cell or z con/itut+ life4 ,x is true t we may n yet "k ! s\rce ( ?is c5trosome4 ,we d n "k :e!r x is h&$ d[n f g5]ation to g5]ation l ! nucleus1 or :e!r x c be made anew out ( ! cell sub/ance 9 ! life ( an ord9>y cell4 ,b ?is is n mat]ial to its recognition z an organ ( importance 9 ! cell activity4 ,?us ! cell proves itself n to2 be a bit ( nucle> matt] surr\nd$ by second>y p>ts1 b a community ( sev]al p]haps equally important int]relat$ memb]s4 ,ano!r s]ies ( obs]vations weak5$ ! cell doctr9e 9 an entirely diff]5t direction4 ,x _h be5 assum$ t ! body ( ! multicellul> animal or plant 0 made ( indep5d5t units4 ,microscopi/s ( a few ye>s ago began to sugge/ t ! cells are 9 reality n sep>at$ f ea* o!r1 b are all connect$ by protoplasmic fibres4 ,9 q a numb] ( diff]5t k9ds ( tissue x has be5 det]m9$ t f9e ?reads ( protoplasmic mat]ial lead f "o cell to ano!r 9 su* a way t ! cells are 9 vital connection4 ,! claim has be5 made t !re is ?us a protoplasmic connection betwe5 all ! cells ( ! body ( ! animal1 & t ?us ! animal or plant1 in/ead ( consi/+ ( a l>ge numb] ( sep>ate indep5d5t cells1 consi/s ( "o great mass ( liv+ matt] :i* is aggregat$ into little c5tres1 ea* commonly hold+ a nucleus4 ,su* a conclusion is n yet demon/rat$1 nor is its significance v cle> %\ld x prove to be a fact2 b x is pla9 t su* sugge/ions q decid$ly modify ! conception ( ! body z a community ( indep5d5t cells4 ,!re is yet ano!r l9e ( ?\ght :i* is weak5+ ?is e>ly conception ( ! cell doctr9e4 ,!re is a gr[+ conviction t ! view ( ! organism1 simply z ! sum ( ! activities ( ! individual cells1 is n a correct und]/&+ ( x4 ,accord+ to ?is extreme position1 a liv+ ?+ c h no organization until x appe>s z ! result ( cell multiplication4 ,to take a concrete case1 ! egg ( a />fi% c n possess any organization correspond+ to ! />fi%4 ,! egg is a s+le cell1 & ! />fi% a community ( cells4 ,! egg c1 !re=e1 no m conta9 ! organization ( a />fi% ?an a hunt] 9 ! backwoods c conta9 )9 himself ! organization ( a great metropolis4 ,! desc5dants ( individuals l ! hunt] may unite to =m a city1 & ! desc5dants ( ! egg cell may1 by comb9+1 give rise to ! />fi%4 ,b nei!r c ! man conta9 )9 himself ! organization ( ! city1 nor ! egg t ( ! />fi%4 ,x is1 p]haps1 true t su* an extreme position ( ! cell doctr9e has n be5 held by any "o1 b ?\ghts v closely approximat+ to ?is view h be5 held by ! lead+ advocates ( ! cell doctr9e1 & h beyond "q be5 ! inspiration ( ! developm5t ( t doctr9e4 ,b c]ta9ly no su* conception ( ! significance ( cell /ructure w\ld long] be held4 ,9 spite ( ! fact t ! egg is a s+le cell1 x is impossible to avoid ! belief t 9 "s way x conta9s ! />fi%4 ,we ne$ n1 ( c\rse1 ?9k ( x z conta9+ ! /ructure ( a />fi%1 b we are =c$ to conclude t 9 "s way its /ructure is su* t x conta9s ! />fi% pot5tially4 ,! relation ( its p>ts & ! =ces !re9 are su* t1 :5 plac$ "u prop] conditions1 x develops into a />fi%4 ,ano!r egg plac$ "u id5tical conditions w develop into a sea ur*91 & ano!r into an oy/]4 ,if ^! ?ree eggs h ! p[] ( develop+ into ?ree diff]5t animals "u id5tical conditions1 x is evid5t t !y mu/ h correspond+ diff]5ces 9 spite ( ! fact t ea* is a s+le cell4 ,ea* mu/ 9 "s way conta9 its correspond+ adult4 ,9 o!r words1 ! organization mu/ be )9 ! cells1 & h5ce n simply produc$ by ! associations ( cells4 ,ov] ?is subject !re has be5 a deal ( puzzl+ & n a little exp]im5tation4 ,! pres5ce ( "s sort ( organization 9 ! egg is cle>--b :at is meant by ?is /atem5t is n q s cle>4 ,is ?is adult organization 9 ! :ole egg or only 9 its nucleus1 & especially 9 ! *romosomes :i*1 z we h se51 conta9 ! h]$it>y traits8 ,:5 ! egg beg9s to divide does ea* ( ! fir/ two cells /ill conta9 pot5tially ! organization ( ! :ole adult1 or only "o half ( x8 ,is ! developm5t ( ! egg simply ! unfold+ ( "s /ructure already pres5t2 or is ! /ructure con/antly develop+ into m & m complicat$ conditions ow+ to ! br++ ( its p>ts into new relations8 ,to answ] ^! que/ions exp]im5t]s h be5 engag$ 9 divid+ develop+ eggs into pieces to det]m9e :at p[]s are /ill possess$ by ! fragm5ts4 ,! results ( su* exp]im5ts are z yet r conflict+1 b x is evid5t en\gh f !m t we c no long] look ^u ! egg cell z a simple undiff]5tiat$ cell4 ,9 "s way x already conta9s ! *>act]s ( ! adult1 & :5 we rememb] t ! *>act]s ( ! adult :i* are to be develop$ f ! egg are already det]m9$1 ev5 to _m m9ute details--su*1 = in/ance1 z ! inh]itance ( a cong5ital m>k--x becomes evid5t t ! egg is a body ( extraord9>y complexity4 ,& yet ! egg is no?+ m ?an a s+le cell agree+ ) o!r cells 9 all its g5]al *>act]s4 ,x is cle>1 !n1 t we mu/ look ^u organization z some?+ sup]ior to cells & some?+ exi/+ )9 !m1 or at lea/ )9 ! egg cell1 & controll+ its developm5t4 ,we are =c$ to believe1 fur!r1 t !re may be z important diff]5ces betwe5 two cells z !re are betwe5 two adult animals or plants4 ,9 "s way !re mu/ be conceal$ )9 ! two cells :i* con/itute ! egg ( ! />fi% & ! man diff]5ces :i* correspond to ! diff]5ces betwe5 ! />fi% & ! man4 ,organization1 9 o!r words1 is sup]ior to cell /ructure1 & ! cell itself is an organization ( small] units4 ,z ! result ( ^! v>i\s consid]ations !re has be51 9 rec5t ye>s1 some?+ ( a reaction aga9/ ! cell doctr9e z =m]ly held4 ,:ile ! /udy ( cells is /ill reg>d$ z ! key to ! int]pretation ( life ph5om5a1 biologi/s are see+ m & m cle>ly t !y mu/ look deep] ?an simple cell /ructure = _! explanation ( ! life processes4 ,:ile ! /udy ( cells has ?r[n an imm5se am\nt ( light ^u life1 we seem h>dly ne>] ! c5tre ( ! problem ?an we 7 be=e ! beg9n+ ( ! s]ies ( discov]ies inaugurat$ by ! =mulation ( ! doctr9e ( protoplasm4 ,fundam5tal ,vital ,activities z ,locat$ 9 ,cells4--,we are n[ 9 position to ask :e!r our k ( cells has aid$ u 9 f9d+ an explanation ( ! fundam5tal vital actions to :i*1 z we h se51 life processes are to be r$uc$4 ,! f\r prop]ties ( irritability1 contractibility1 assimilation1 & reproduction1 belong to ^! vital units--! cells1 & x is ^! prop]ties :i* we are try+ to trace to _! s\rce z a f\ndation ( vital activity4 ,we may fir/ ask :e!r we h any facts :i* indicate t any special p>ts ( ! cell are associat$ ) any ( ^! fundam5tal activities4 ,! fir/ fact t /&s out cle>ly is t ! nucleus is connect$ mo/ intimately ) ! process ( reproduction & especially ) h]$ity4 ,?is has long be5 believ$1 b has n[ be5 cle>ly demon/rat$ by ! exp]im5ts ( cutt+ into fragm5ts ! cell bodies ( unicellul> animals4 ,z already notic$1 ^? pieces :i* possess a nucleus are able to cont9ue _! life & reproduce !mselves1 :ile ^? )\t a nucleus are incapable ( reproduction4 ,) great] =ce /ill is ! fact %[n by ! process ( f]tilization ( ! egg4 ,! egg is v l>ge & ! male reproductive cell is v small1 & ! am\nt ( mat]ial :i* ! (fspr+ d]ives f its "m is v great comp>$ ) t :i* x d]ives f its fa!r4 ,b ! *ild inh]its equally f fa!r & "m1 & h5ce we mu/ f9d ! h]$it>y traits h&$ d[n 9 "s elem5t :i* ! (fspr+ obta9s equally f fa!r & "m4 ,z we h se5 7,figs4 #cd-dd71 ! only elem5t :i* answ]s ?is dem& is ! nucleus1 & m p>ticul>ly ! *romosomes ( ! nucleus4 ,cle>ly en\gh1 !n1 we mu/ look ^u ! nucleus z ! special ag5t 9 reproduction ( cells4 ,aga91 we h app>5tly conclusive evid5ce t ! nucleus controls t "p ( ! assimilative process :i* we h spok5 ( z ! con/ructive processes4 ,! metabolic processes ( life are bo? con/ructive & de/ructive4 ,by ! =m]1 ! mat]ial tak5 into ! cell 9 ! =m ( food is built up into cell tissue1 su* z l991 microsomes1 etc41 &1 by ! latt]1 ^! products are to a great] or less ext5t brok5 to pieces aga9 to lib]ate _! en]gy1 & ?us give rise to ! activities ( ! cell4 ,if ! de/ructive processes 7 to g on alone ! organism might cont9ue to manife/ its life activities = a "t until x _h exhau/$ ! products /or$ up 9 its body = su* purposes1 b x w\ld die f ! lack ( m mat]ial = de/ruction4 ,life is n complete )\t bo? processes4 ,n[1 9 ! life ( ! cell we may app>5tly attribute ! de/ructive processes to ! cell sub/ance & ! con/ructive processes to ! nucleus4 ,9 a cell :i* has be5 cut into fragm5ts ^? pieces )\t a nucleus cont9ue to %[ ! ord9>y activities ( life = a "t1 b !y d n live v long 7,fig4 #be74 ,! fragm5t is unable to assimilate its food suffici5tly to build up m mat]ial4 ,s long z x /ill reta9s )9 itself a suffici5cy ( already =m$ tissue = its de/ructive metabolism1 x c cont9ue to move ar\nd actively & behave l a complete cell1 b ev5tually x dies f />vation4 ,on ! o!r h&1 ^? fragm5ts :i* reta9 a piece ( ! nucleus1 ev5 ?\gh !y h only a small portion ( ! cell sub/ance1 fe$1 assimilate1 & gr[2 9 o!r words1 !y c>ry on n only ! de/ructive b also ! con/ructive *anges4 ,pla9ly1 ?is means t ! nucleus controls ! con/ructive processes1 al?\gh x does n necess>ily mean t ! cell sub/ance has no %>e 9 ^! con/ructive processes4 ,)\t ! nucleus ! cell is unable to p]=m ^? processes1 :ile x is able to c>ry on ! de/ructive processes readily en\gh4 ,! nucleus controls1 ?\gh x may n entirely c>ry on1 ! con/ructive metabolism4 ,x is equally cle> t ! cell sub/ance is ! seat ( mo/ ( ! de/ructive processes :i* con/itute vital action4 ,! cell sub/ance is irritable1 & is end[$ ) ! p[] ( contractility4 ,cell fragm5ts )\t nucleii are s5sitive en\gh1 & c move ar\nd z readily z normal cells4 ,moreov]1 ! v>i\s fibres :i* surr\nd ! c5trosomes 9 cell division & ^: contractions & expansions1 z we h se51 pull ! *romosomes ap>t 9 cell division1 are p>ts ( ! cell sub/ance4 ,all ( ^! are ! results ( de/ructive metabolism1 & we mu/1 !re=e1 conclude t de/ructive processes are seat$ 9 ! cell sub/ance4 ,! c5trosome is too problematical z yet = mu* comm5t4 ,x appe>s to be a piece ( ! ma*9]y = br++ ab\t cell division1 b beyond ?is x is n safe to make any /atem5ts4 ,9 brief1 !n1 ! cell body is a ma*9e = c>ry+ on de/ructive *emical *anges1 & lib]at+ f ! comp\nds ?us brok5 to pieces _! inclos$ en]gy1 :i* is at once conv]t$ into motion or heat or "s o!r =m ( active en]gy4 ,?is *emical de/ruction is1 h[ev]1 possible only aft] ! *emical comp\nds h become a "p ( ! cell4 ,! cell1 !re=e1 possesses a nucleus :i* has ! p[] ( enabl+ x to assimilate its food--t is1 to conv]t x into its own sub/ance4 ,! nucleus fur!r conta9s a m>vell\s mat]ial--*romat9--:i* 9 someway ex]cises a controll+ influ5ce 9 its life & is h&$ d[n f "o g5]ation to ano!r by cont9u\s desc5t4 ,la/ly1 ! cell has ! c5trosome1 :i* br+s ab\t cell division 9 su* a mann] t ?is *romat9 mat]ial is divid$ equally among ! subsequ5t desc5dants1 & ?us insures t ! daught] cells %all all be equival5t to ea* o!r & to ! "m cell4 ,we mu/ !re=e look ^u ! organic cell z a little eng9e ) admirably adapt$ p>ts4 ,)9 ?is eng9e *emical activity is excit$4 ,! fuel suppli$ to ! eng9e is comb9$ by *emical =ces ) ! oxyg5 ( ! air4 ,! vig\r ( ! oxidation is p>tly dep5d5t ^u temp]ature1 j z x is 9 any o!r oxidation process1 & is ( c\rse dep5d5t ^u ! pres5ce ( fuel to be oxidiz$1 & air to furni% ! oxyg54 ,unless ! fuel is suppli$ & ! air has free access to x1 ! ma*9e /ops1 ! cell dies4 ,! en]gy lib]at$ 9 ?is ma*9e is conv]t$ into motion or "s o!r =m4 ,we d n inde$ und]/& ! con/ruction ( ! ma*9e well en\gh to expla9 ! exact me*anism by :i* ?is conv]sion takes place1 b t !re is su* a me*anism c n be d\bt$1 & ! /ructure ( ! cell is c]ta9ly complex en\gh to give pl5ty ( room = x4 ,! irritability ( ! cell is easily und]/ood2 =1 s9ce x is made ( v un/able *emical comp\nds1 any slight di/urbance or /imulation on "o "p w t5d to upset its *emical /ability & produce reaction2 & ?is is :at is meant by irritability4 ,or1 aga91 we may look ^u ! cell z a little *emical laboratory1 :]e *emical *anges are con/antly occurr+4 ,^! *anges we d n inde$ und]/&1 b !y are und\bt$ly *emical *anges4 ,! result is t "s comp\nds are pull$ to pieces & "p ( ! fragm5ts lib]at$ or excret$1 :ile o!r p>ts are reta9$ & built into o!r m complex comp\nds4 ,! comp\nds ?us manufactur$ are reta9$ 9 ! cell body1 & x gr[s 9 bulk4 ,?is cont9ues until ! cell becomes too big1 & !n x divides4 ,if a ma*9e is brok5 x ceases to c>ry on its prop] duties1 & if ! p>ts are badly brok5 x is ru9$4 ,s ) ! cell4 ,if x is brok5 by any means1 me*anical1 !rmal1 or o!rwise1 x ceases to run--we say x dies4 ,x has )9 itself great p[] ( repair+ injury1 & !re=e x does n cease to act until ! injury is s great z to be beyond repair4 ,?us x only /ops its motion :5 ! ma*9]y has become s badly injur$ z to be beyond hope ( repair1 & h5ce ! cell1 aft] once ceas+ its action1 c nev] resume x aga94 ,!re are1 ( c\rse1 o!r functions ( liv+ ?+s besides ! few simple ones :i* we h consid]$4 ,b ^! are ! fundam5tal ones2 & if we c r$uce !m to an intelligible explanation1 we may feel t we h really grasp$ ! ess5ce ( life4 ,if we und]/& h[ ! cell c move & gr[ & reproduce itself1 we may re/ assur$ t ! o!r ph5om5a ( life foll[ z a natural consequ5ce4 ,if1 !re=e1 we h obta9$ an und]/&+ ( ^! fundam5tal vital ph5om5a1 we h accompli%$ our object ( compreh5d+ ! life ph5om5a 9 our *emical & me*anical laws4 ,b h we ?us r$uc$ ^! fundam5tal ph5om5a to an intelligible explanation8 ,x mu/ be ackn[l$g$ t we h n4 ,we h r$uc$ !m to ! action ( *emical =ces act+ 9 a ma*9e4 ,b ! ma*9e itself is un9telligible4 ,! organic cell is no m intelligible to u ?an is ! body z a :ole4 ,! *emical und]/&+ :i* we ?\ght we _h a few ye>s ago 9 protoplasm has fail$ u1 & no?+ has tak5 its place ,we h no conception ( :at may be ! primitive life sub/ance4 ,all we c say is t ?is mo/ m>vell\s ( all natural ph5om5a occurs only )9 t peculi> piece ( ma*9]y :i* we call ! cell1 & t x is ! result ( ! action ( physical =ces 9 t ma*9e4 ,h[ ! ma*9e acts1 or ev5 ! /ructure ( ! ma*9e1 we are z f> f und]/&+ z we 7 fifty ye>s ago4 ,! solution has retreat$ be=e u ev5 fa/] ?an we h advanc$ t[>d x4 ,summ>y4--,we may n[ notice 9 a brief summ>y ! position :i* we h rea*$4 ,9 our attempt to expla9 ! liv+ organism on ! pr9ciple ( ! ma*9e1 we are v successful s f> z second>y problems are conc]n$4 ,dige/ion1 circulation1 respiration1 & motion are readily solv$ ^u *emical & me*anical pr9ciples4 ,ev5 ! ph5om5a ( ! n]v\s sy/em are1 9 a measure1 capable ( compreh5sion )9 a me*anical =mula1 leav+ out ( acc\nt ! purely m5tal ph5om5a :i* c]ta9ly h n be5 t\*$ by ! inve/igation4 ,all ( ^! ph5om5a are r$ucible to a few simple fundam5tal activities1 & ^! fundam5tal activities we f9d manife/$ by simple bits ( liv+ matt] un9cumb]$ by ! complicat$ ma*9]y ( organisms4 ,) ! few fundam5tal prop]ties ( ^! bits ( organic matt] we c con/ruct ! complicat$ life ( ! high] organism4 ,:5 we come1 h[ev]1 to /udy ^! simple bits ( matt]1 !y prove to be any?+ b simple bits ( matt]4 ,!y1 too1 are pieces ( complicat$ me*anism ^: action we d n ev5 hope to und]/&4 ,t _! action is dep5d5t ^u _! ma*9]y is evid5t en\gh f ! simple description ( cell activity :i* we h notic$4 ,t ^! fundam5tal vital prop]ties are to be expla9$ z ! result ( *emical & me*anical =ces act+ ?r\gh ?is ma*9]y1 c n be d\bt$4 ,b h[ ?is occurs or :at con/itutes ! guid+ =ce :i* corresponds to ! eng9e] ( ! ma*9e1 we d n "k4 ,?us our me*anical explanation ( ! liv+ ma*9e lacks a f\ndation4 ,we c und]/& tol]ably well ! build+ ( ! sup]/ructure1 b ! f\ndation /ones ^u :i* t /ructure is built are un9telligible to u4 ,! runn+ ( ! liv+ ma*9e is ?us only 9 "p und]/ood4 ,! liv+ organism is a ma*9e or1 x is bett] to say1 x is a s]ies ( ma*9es "o )9 ! o!r4 ,z a :ole x is a ma*9e1 & its p>ts are sep>ate ma*9es4 ,ea* "p is fur!r made up ( /ill small] ma*9es until we rea* ! realm ( ! microscope4 ,"h /ill we f9d ! same /ory4 ,ev5 ! p>ts =m]ly call$ units1 prove to be ma*9es1 & :5 we recognize ! complexity ( ^! cells & _! m>vell\s activities1 we are ready to believe t we may f9d /ill fur!r ma*9es )94 ,& ?us vital activity is r$uc$ to a complex ( ma*9es1 all act+ 9 h>mony ) ea* o!r to produce toge!r ! "o result--life4 ,,"p ,,ii4 ,,! ,,build+ ,,( ,,! ,,liv+ ,,ma*9e4 99 99 99 99 99 ,,*apt] ,,iii4 ,,! ,,factors ,,conc]n$ ,,9 ,,! ,,build+ ,,( ,,! ,,liv+ ,,ma*9e4 ,hav+ n[ outl9$ ! results ( our /udy into ! me*anism ( ! liv+ ma*9e1 we turn our att5tion next to ! m difficult problem ( ! me?od by :i* ?is ma*9e 0 built4 ,f ! facts :i* we h be5 consid]+ 9 ! la/ two *apt]s x is evid5t t ! problem we h be=e u is a me*anical r ?an a *emical "o4 ,( c\rse1 *emical =ces lie at ! bottom ( vital activity1 & we mu/ look ^u ! =ce ( *emical aff9ity z ! fundam5tal p[] to :i* ! problems mu/ be ref]r$4 ,b a *emical explanation w evid5tly n suffice = our purpose2 = we h absolutely no reason = believ+ t ! ph5om5a ( life c occur z ! results ( ! *emical prop]ties ( any comp\nd1 h[ev] complex4 ,! simple/ kn[n =m ( matt] :i* manife/s life is a ma*9e1 & ! problem ( ! orig9 ( life mu/ be ( ! orig9 ( t ma*9e4 ,are !re any =ces 9 nature :i* are ( a sort z to enable u to use !m to expla9 ! build+ ( ma*9es8 ,plants & animals are ! only ma*9es :i* nature has produc$4 ,!y are ! only in/ances 9 nature ( a /ructure built ) its p>ts h>moni\sly adju/$ to ea* o!r to ! p]=mance ( c]ta9 ends4 ,all o!r ma*9es ) :i* we are acqua9t$ 7 made by man1 & 9 mak+ !m intellig5ce came 9 to adapt ! p>ts to ea* o!r4 ,b 9 ! liv+ organism is a simil>ly adapt$ ma*9e made by natural means r ?an artificial4 ,h[ 7 !y built8 ,does nature1 ap>t f human intellig5ce1 possess =ces :i* c a*ieve su* results8 ,"h aga9 we mu/ attack ! problem f :at seems to be ! wrong end4 ,app>5tly x w\ld be simpl] to discov] ! me?od ( ! manufacture ( ! simple/ ma*9e r ?an ! m complex ones4 ,b ?is has prov$ contr>y to ! fact4 ,p]haps ! *ief reason is t ! simple/ liv+ ma*9e is ! cell ^: /udy mu/ always involve ! use ( ! microscope1 & = ?is reason is m difficult4 ,p]haps x is because ! problem is really a m difficult "o ?an to expla9 ! build+ ( ! m complex ma*9es out ( ! simpl] ones4 ,at all ev5ts1 ! la/ fifty ye>s h told u mu* ( ! me?od ( ! build+ ( ! complex ma*9es out ( ! simpl] ones1 :ile we h z yet n ev5 a h9t z to ! solution ( ! build+ ( ! simple/ ma*9e f ! inanimate _w4 ,our att5tion mu/1 !re=e1 be fir/ direct$ to ! me?od by :i* nature has con/ruct$ ! complex ma*9es :i* we f9d fill+ ! _w to-day 9 ! =m ( animals & plants4 ,hi/ory ( ! ,liv+ ,ma*9e4--,9 ! fir/ place1 we mu/ notice t ^! ma*9es h n be5 fa%ion$ sudd5ly or rapidly1 b h be5 ! result ( a v sl[ gr[?4 ,!y h _h a hi/ory ext5d+ v f> back into ! pa/ = a p]iod ( ye>s :i* we c only indef9itely e/imate1 b c]ta9ly rea*+ into ! millions4 ,z we look ov] ?is pa/ hi/ory 9 ! light ( our pres5t k we see t :atev] h be5 ! =ces :i* h be5 conc]n$ 9 ! con/ruction ( ^! ma*9es !y h act$ v sl[ly4 ,x has tak5 c5turies1 &1 inde$1 ?\s&s ( ye>s1 to take ! successive /eps :i* h be5 necess>y 9 ?is con/ruction4 ,secondly1 we notice t ! ma*9es h be5 built up /ep by /ep1 "o feature be+ add$ to ano!r ) ! sl[ly progress+ ages4 ,?irdly1 we notice t 9 "o respect ?is con/ruction ( ! liv+ ma*9e by nature's processes has be5 diff]5t f our ord9>y me?od ( build+ ma*9es4 ,our me?od ( build+ puts ! p>ts gradually into place 9 su* a way t until ! ma*9e is f9i%$ x is incapable ( p]=m+ its functions4 ,! half-built eng9e is z useless & z p[]less z s mu* crude iron4 ,its p[] ( action only appe>s aft] ! la/ "p is fitt$ into place & ! ma*9e f9i%$4 ,b nature's process 9 ma*9e build+ is diff]5t4 ,e /ep 9 ! process1 s f> z we c trace x at lea/1 has produc$ a complete ma*9e4 ,s f> back z we c foll[ ?is hi/ory we f9d t at e po9t ! ma*9e 0 s complete z to be always end[$ ) motion & life activity4 ,nature's me?od has be5 to take simpl] types ( ma*9es & sl[ly *ange !m into m complicat$ ones )\t at any mom5t impair+ _! vig\r4 ,x is some?+ z if ! /eam eng9e ( ,watt %\ld be sl[ly *ang$ by add+ piece aft] piece until !re 0 f9ally produc$ ! mod]n quadruple expansion eng9e1 b all ?is *ange be+ made ^u ! orig9al eng9e )\t once /opp+ its motion4 ,illu/ration3 ,,fig4 #de4 ,a gr\p ( cells result+ f division1 repres5t+ ! fir/ /ep 9 ma*9e mak+4 ,?is gradual con/ruction ( ! liv+ ma*9es has be5 call$ ,organic ,evolution1 or ! ,!ory ( ,desc5t4 ,x w be necess>y = u1 9 ord] to compreh5d ! problem :i* we h be=e u1 to briefly outl9e ! c\rse ( ?is evolution4 ,our />t+ po9t 9 ?is hi/ory mu/ be ! cell1 = su* is ! e>lie/ & simple/ =m ( liv+ ?+ ( :i* we h any trace4 ,?is cell is1 ( c\rse1 already a ma*9e1 & we mu/ pres5tly return to ! problem ( its orig94 ,at pres5t we w assume ?is cell z a />t+ po9t end[$ ) its fundam5tal vital p[]s4 ,x 0 s5sitive1 x c\ld feel1 gr[1 & reproduce itself4 ,f su* a simple ma*9e1 ?us end[$1 ! hi/ory has be5 some?+ z foll[s3 ,9 reproduc+ itself ?is ma*9e1 z we h already se51 simply divid$ itself into two halves1 ea* l ! o!r4 ,at fir/ all ! p>ts ?us aris+ sep>at$ f ea* o!r & rema9$ indep5d5t4 ,b s long z ?is habit cont9u$ !re c\ld be little advance4 ,aft] a "t "s ( ! cells fail$ to sep>ate aft] division1 b rema9$ cl++ toge!r 7,fig4 #de74 ,! cells ( su* a mass mu/ h be5 at fir/ all alike2 b1 aft] a little1 diff]5ces began to appe> among !m4 ,^? on ! outside ( ! mass 7 diff]5tly affect$ by _! surr\nd+s f ^? 9 ! int]ior1 & soon ! cells began to %>e among !mselves ! diff]5t duties ( life4 ,! cells on ! outside 7 bett] situat$ = protection & captur+ food1 :ile ^? on ! inside c\ld n readily seize food = !mselves1 & took ^u !mselves ! duty ( dige/+ ! food :i* 0 h&$ to !m by ! out] cells4 ,ea* ( ^! sets ( cells c\ld n[ c>ry on its own special duties to bett] advantage1 s9ce x 0 fre$ f o!r duties1 & ?us ! :ole mass ( cells 0 bett] s]v$ ?an :5 ea* cell tri$ to d ev]y?+ = itself4 ,?is 0 ! fir/ /ep 9 ! build+ ( ! ma*9e out ( ! active cells 7,fig4 #df74 ,f su* a />t+ po9t ! subsequ5t hi/ory has be5 ev] bas$ ^u ! same pr9ciple4 ,!re has be5 a con/ant sep>ation ( ! diff]5t functions ( life among gr\ps ( cells1 & z ! hi/ory w5t on ?is division ( labor among ! diff]5t p>ts became great] & great]4 ,gr\p aft] gr\p ( cells 7 set ap>t = "o special duty aft] ano!r1 & ! result 0 a l>g] & ev] m complicat$ mass ( cells1 ) a great] & great] diff]5tiation among !m4 ,9 ?is build+ ( ! ma*9e !re 0 no "t :5 ! ma*9e 0 n active4 ,at all po9ts ! ma*9e 0 alive & functional1 b ea* /ep made ! total function ( ! ma*9e a little m accurately p]=m$1 & h5ce rais$ some:at ! totality ( life p[]s4 ,?is p>cell+ out ( ! diff]5t duties ( life to gr\ps ( cells cont9u$ age aft] age1 ea* /ep be+ a little advance ov] ! la/1 until ! result has be5 ! liv+ ma*9e z we "k x 9 its highe/ =m1 ) its num]\s organs1 all int]relat$ 9 su* a way z to =m a h>moni\sly act+ :ole4 ,illu/ration3 ,,fig4 #df4 ,a lat] /ep 9 ma*9e build+ 9 :i* ! out] cells h acquir$ diff]5t =m & function f ! inn] cells3 ec1 ! out] cells1 ^: duties are protective2 en1 ! inn] cells engag$ 9 dige/+ food4 ,b a second pr9ciple 9 ?is gr[? ( ! ma*9e 0 ne$$ to produce ! v>iety :i* is f\nd 9 nature4 ,z ! diff]5t cells 9 ! multicellul> mass became associat$ into gr\ps = diff]5t duties1 ! me?od ( su* division ( labor 0 n alike 9 all ma*9es4 ,a city 9 ,*9a & "o 9 ,am]ica are alike made up ( individuals1 & ! fundam5tal ne$s ( ! ,*9aman & ! ,am]ican are alike4 ,b diff]5ces 9 indu/rial & political conditions h produc$ diff]5t comb9ations & associations1 s t ,pek9 is wond]fully unlike ,new ,york4 ,s 9 ^! e>ly develop+ ma*9es1 q a v>iety ( me?od ( organization 0 adopt$ by ! diff]5t gr\ps4 ,n[ z soon z any special type ( organization 0 adopt$ by any animal or plant1 ! pr9ciple ( h]$ity transmitt$ ! same k9d ( organization to its desc5dants1 & !re ?us arose l9es ( desc5t diff]+ f ea* o!r1 ea* l9e hav+ its own me?od ( organization4 ,z we foll[ ! hi/ory ( ea* l9e ! same ?+ is repeat$4 ,we f9d t ! repres5tatives ( ea* l9e aga9 sep>ate into gr\ps1 ea* ( :i* has acquir$ "s new type ( organization1 & !re has ?us be5 a con/ant div]g5ce ( ^! l9es ( desc5t 9 an indef9ite numb] ( directions4 ,! memb]s ( ! diff]5t l9es ( desc5t all %[ a fundam5tal lik5ess ) ea* o!r s9ce !y reta9 ! fundam5tal *>act]s ( _! common ance/or1 b !y %[ also ! diff]5ces :i* !y h !mselves acquir$4 ,& ?us ! process is repeat$ ov] & ov] aga94 ,?is hi/ory ( ! gr[? ( ^! diff]5t ma*9es has ?us be5 "o ( div]g5ce f common c5tres1 & is to be diagrammatically express$ aft] ! fa%ion ( a bran*+ tree4 ,! end ( ea* bran* repres5ts ! highe/ /ate ( p]fection to :i* ea* l9e has be5 c>ri$4 ,"o o!r po9t 9 ?is hi/ory mu/ be not$4 ,z ! developm5t ( ! complication ( ! ma*9e progress$ ! possibility ( fur!r progress has be5 con/antly n>r[$4 ,:5 ! hi/ory ( ^! ma*9es began z a simple mass ( cells1 !re 0 a possibility ( an almo/ endless v>iety ( me?ods ( organization4 ,b z a di/9ct type ( organization 0 adopt$ by "o & ano!r l9e ( desc5dants all subsequ5t productions 7 limit$ ?r\gh ! law ( h]$ity to ! g5]al l9e ( organization adopt$ by _! ance/ors4 ,) ea* age ! fur!r gr[? ( su* ma*9es mu/ consi/ 9 ! fur!r developm5t 9 ! p]fection ( its p>ts1 & n 9 ! adoption ( any new sy/em ( organization4 ,h5ce x is t ! hi/ory ( ! liv+ ma*9e has %[n a t5d5cy t[>d developm5t along a few well-m>k$ l9es1 & al?\gh ?is complication becomes great]1 we /ill see ! same fundam5tal s*eme ( organization runn+ ?r\gh ! :ole4 ,z ! ages h progress$ ! ma*9es h become m p]fect 9 ! adju/m5t ( _! p>ts1 i4e41 !y h become m p]fect ma*9es1 b ! hi/ory has be5 simply t ( p]fect+ ! e>ly ma*9es r ?an ! production ( new types4 ,evid5ce = ?is ,hi/ory4--,z j outl9$1 we see t ! liv+ ma*9es h be5 gradually br\ght into _! pres5t condition by a process :i* has be5 call$ organic evolution4 ,b we mu/ pause = a mom5t to ask :at is our evid5ce t su* has be5 ! hi/ory ( ! liv+ ma*9e4 ,! :ole possibility ( und]/&+ liv+ nature dep5ds ^u our accept+ ?is hi/ory & f9d+ an explanation ( x4 ,at ! outset we h ! "q ( fact1 & we mu/ notice ! gr\nds ^u :i* we /& 9 assum+ ?is hi/ory to be z outl9$4 ,?is problem is ! "o :i* has occupi$ su* a prom95t place 9 ! sci5tific _w dur+ ! la/ =ty ye>s1 & :i* has contribut$ s l>gely t[>d mak+ mod]n biology su* a diff]5t subject f ! e>li] /udies ( natural hi/ory4 ,x is simply ! evid5ce = organic evolution1 or ! !ory ( desc5t4 ,! subject has = =ty ye>s be5 ?or\ghly sift$ & te/$ by e conceivable sort ( te/4 ,z a result ( ! int]e/ 9 ! "q !re has be5 disclos$ an imm5se mass ( evid5ce1 relevant & irrelevant4 ,z ! evid5ce has accumulat$ x has become m & m evid5t t ! evolution !ory mu/ be recogniz$ z ! only "o :i* is 9 accord ) ! facts1 & ! outcome has be5 a practical unanimity among ?9k]s t ! !ory ( desc5t mu/ be ! f\ndation ( our fur!r /udy4 ,! evid5ce :i* has =c$ ?is conclusion ^u sci5ti/s we mu/ /op = a mom5t to consid]1 s9ce x be>s v directly ^u ! subject we are /udy+4 ,hi/orical4--,! fir/ s\rce ( evid5ce is naturally a hi/orical "o4 ,?is long hi/ory ( ! con/ruction ( ! liv+ ma*9e has left its record 9 ! rocks :i* =m ! e>?'s surface4 ,dur+ ?is long p]iod ! rocks ( ! e>?'s cru/ h be5 deposit$1 & 9 ^! rocks h be5 left samples ( _m ( ! /eps 9 ?is hi/ory ( ma*9e build+4 ,! hi/ory c be trac$ by ! /udy ( ^! samples j z ! hi/ory ( any ma*9e might be trac$ f a /udy ( ! models 9 a pat5t (fice4 ,"o might v easily trace1 ) mo/ /rict accuracy & m9ute detail1 ! hi/ory ( ! pr9t+ ma*9e f ! models :i* are pres]v$ 9 ! pat5t (fices & else:]e4 ,s is x ) ! hi/ory ( ! liv+ ma*9e4 ,to be sure1 ! hi/ory is r incomplete & at times difficult to read4 ,_m a p]iod 9 ! developm5t has left no samples = our inspection & mu/ be int]pret$ 9 our hi/ory betwe5 :at w5t be=e & :at comes aft]4 ,_m ( ! ma*9es1 especially ! e>ly ones1 7 made ( su* fragile mat]ial t !y c\ld n be pres]v$ 9 ! rocks4 ,9 _m a case1 too1 ! rocks 9 :i* ! specim5s 7 deposit$ h be5 subject$ to su* a v>iety ( heat+s & pressures1 t !y h be5 twi/$ out ( %ape & ev5 cru%$ out ( recognizable =m4 ,b 9 spite ( ?is ! record is %[+ itself m complete ea* ye>4 ,our paleontologi/s are op5+ lay] aft] lay] ( ^! rocks1 & ?us exam9+ ea* ye> new pages 9 nature's hi/ory4 ,! m rec5t epo*s 9 ! hi/ory h be5 already read ) almo/ hi/oric accuracy4 ,f !m we h le>n$ 9 great detail h[ ! f9i%+ t\*es 7 giv5 to ^! ma*9es1 & are able to trace ) accuracy h[ ! some:at m g5]aliz$ =ms ( e>li] days 7 *ang$ to produce our mod]n animals4 ,?is fossil record has giv5 u our be/ k ( ! c\rse by :i* ! pres5t liv+ _w has be5 br\ght into its exi/+ condition4 ,b its accuracy is l>gely conf9$ to ! rec5t p]iods4 ,( ! v e>ly hi/ory fossils tell u little or no?+4 ,all ! e>ly rocks1 :i* we may believe 7 =m$ dur+ ! p]iod :5 ! fir/ /eps 9 ?is ma*9e build+ 7 tak51 h be5 s *ang$ by heat & pressure t :atev] specim5s !y may h orig9ally conta9$ h be5 cru%$ out ( %ape4 ,fur!rmore1 ! e>lie/ organisms _h no h>d skeletons1 & x 0 n until liv+ be+s _h develop$ f> en\gh to h h>d p>ts t x 0 possible = !m to leave traces ( !mselves 9 ! rocks4 ,h5ce1 s f> z conc]ns ?is e>lie/ hi/ory1 we c get no record ( x 9 ! rocks4 ,embryological4--,b "h comes 9 ano!r s\rce ( evid5ce :i* helps to fill up ! gap4 ,9 its developm5t e animal to-day beg9s z an egg4 ,?is is a simple cell1 & ! animal goes ?r\gh a s]ies ( *anges :i* ev5tually lead to ! adult4 ,n[ ^! *anges appe> = ! mo/ "p to be p>allel to ! *anges ?r\gh :i* ! e>li] =ms ( life pass$ 9 _! developm5t f ! simple to ! m complicat$ =ms4 ,:]e x is possible to foll[ ! hi/ory ( ! gr\ps ( animals f _! fossil rema9s & comp>e x ) ! hi/ory ( ! individual animal z x progresses f ! egg to ! adult1 !re is f\nd a v decid$ p>allelism4 ,?is p>allelism betwe5 embryology & pa/ hi/ory has be5 ( great s]vice 9 help+ u t[>d ! hi/ory ( ! pa/4 ,at "o "t x 0 believ$ t x 0 ! key :i* w\ld unlock all doors1 & = a decade biologi/s eag]ly pursu$ embryology ) ! expectation t x w\ld solve all problems 9 connection ) ! hi/ory ( animals4 ,! result has be5 some:at disappo9t+4 ,embryology has1 x is true1 be5 ( ! utmo/ s]vice 9 %[+ relation%ips ( =ms to ea* o!r1 & 9 ?us reveal+ pa/ hi/ory4 ,b :ile ?is record is a valuable "o1 x is a record :i* has un=tunately be5 subject to su* modify+ conditions t 9 _m cases its orig9al mean+ has be5 entirely oblit]at$ & x has become wor?less z a hi/orical record4 ,^! imp]fections 9 reg>d to ! record 7 e>ly se5 aft] ! att5tion ( biologi/s 0 s]i\sly turn$ to ! /udy ( embryology1 b x 0 expect$ t x w\ld be possible to correct !m & discov] ! true mean+ und]ly+ ! m app>5t "o4 ,inde$1 9 _m cases ?is has be5 f\nd possible4 ,b _m ( ! modifications are s pr(\nd z to r5d] x impossible to untangle !m & discov] ! true mean+4 ,z a result ! biologi/ to-day is %[+ less confid5ce 9 embryology1 & is turn+ 8 att5tion 9 diff]5t directions z m promis+ ( results 9 ! l9e desir$4 ,b al?\gh ! tea*+s ( embryology h fail$ to realize ! great hopes t 7 plac$ ^u !m1 _! assi/ance 9 ! =mulation ( ?is hi/ory ( ! ma*9e has be5 ( extreme value4 ,_m a bit ( obscurity has be5 cle>$ up :5 ! embryology ( puzzl+ animals has be5 /udi$4 ,_m a relation%ip has be5 made cle>1 & ?is is simply ano!r way ( say+ t a portion ( ?is hi/ory ( life has be5 read4 ,?is aid ( embryology has be5 p>ticul>ly valuable 9 j t "p ( ! hi/ory :]e ! evid5ce f ! /udy ( fossils is want+4 ,! /udy ( fossils1 z we h se51 gives little or no data conc]n+ ! e>ly hi/ory ( liv+ ma*9es2 & x is j "h t embryology has prov$ to be ( ! mo/ value4 ,x is a s\rce ( evid5ce t has told u ( mo/ ( ! /eps 9 ! progress f ! s+le-cell$ animal to ! multicellul> organisms1 & gives u ! cle>e/ idea ( ! fundam5tal pr9ciples :i* h be5 conc]n$ 9 ! evolution ( life & ! con/ruction ( ! complicat$ ma*9e out ( ! simple bit ( protoplasm4 ,9 spite ( its limits1 !re=e1 embryology has contribut$ a l>ge quota ( ! evid5ce :i* we h ( ! evolution ( life4 ,anatomical4--,a ?ird s\rce ( ?is hi/ory is obta9$ f ! facts ( comp>ative anatomy4 ,! ess5tial feature ( ?is subject is ! fact t animals & plants %[ relation%ips4 ,?is fact is "o ( ! mo/ pat5t & yet "o ( ! mo/ sugge/ive facts ( biology4 ,x has be5 recogniz$ f ! v beg9n+ ( ! /udy ( animals & plants4 ,"o _c be ev5 ! mo/ sup]ficial obs]v] )\t see+ t c]ta9 =ms %[ great lik5ess to ea* o!r :ile o!rs are mu* m unlike4 ,! gr\p+ ( animals & plants into ord]s1 g5]a1 & species is dep5d5t ^u ?is relation%ip4 ,if two =ms are alike 9 ev]y?+ except "s slight detail1 !y are commonly plac$ 9 ! same g5us b 9 diff]5t species1 :ile if !y %[ a great] unlik5ess !y may be plac$ 9 sep>ate g5]a4 ,by ?us gr\p+ toge!r =ms accord+ to _! resemblance ! animal & vegetable k+doms are classifi$ into gr\ps subord9ate to gr\ps4 ,! pr9ciple ( relation%ip1 i4e41 fundam5tal simil>ity ( /ructure1 runs ?r\gh ! :ole animal & vegetable k+dom4 ,ev5 ! animals mo/ unlike ea* o!r %[ c]ta9 po9ts ( simil>ity :i* indicates a relation%ip1 al?\gh ( c\rse a di/ant "o4 ,! fact ( su* a relation%ip is too pat5t to dem& m words1 b its significance ne$s to be po9t$ out4 ,:5 we speak ( relation%ip among m5 we always mean hi/orical connection4 ,two bro!rs are closely relat$ because !y h sprung f common p>5ts1 :ile two c\s9s are less closely relat$ because _! common po9t ( orig9 0 f>!r back 9 "t4 ,m widely we speak ( ! relation%ip ( ! ,indo-,european races1 mean+ !reby t back 9 ! hi/ory ( man ^! races _h a common po9t ( orig94 ,we nev] speak ( any real relation ( objects unless !reby we mean to imply hi/orical connection4 ,we are !re=e ju/ifi$ 9 int]pret+ ! manife/ relation%ips ( organisms z po9t+ to hi/ory4 ,p>ticul>ly are we ju/ifi$ 9 ?is conclusion :5 we f9d t ! relation%ips :i* we draw betwe5 ! types ( life n[ 9 exi/5ce run p>allel to ! hi/ory ( ^! types z reveal$ to u by fossils & at ! same "t disclos$ by ! /udy ( embryology4 ,?is subject ( comp>ative anatomy includes a consid]ation ( :at is call$ homology1 & p]haps a concrete example may be in/ructive bo? 9 illu/ration & z sugge/+ ! c\rse :i* nature adopts 9 con/ruct+ h] ma*9es4 ,we speak ( a monkey's arm & a bird's w+ z homolog\s1 al?\gh !y are wond]fully diff]5t 9 appe>ance & adapt$ to diff]5t duties4 ,!y are call$ homolog\s because !y h simil> p>ts 9 simil> relations4 ,?is c be se5 9 ,figs4 #dg & #dh1 :]e x w be se5 t ea* has ! same bones1 al?\gh 9 ! bird's w+ "s ( ! bones h be5 fus$ toge!r & o!rs lo/4 ,_! simil>ity po9ts to a relation%ip1 b _! dissimil>ity tells u t ! relation%ip is a di/ant "o1 & t _! common po9t ( orig9 mu/ h be5 q f> back 9 hi/ory4 ,n[ if we foll[ back ! hi/ory ( ^! two k9ds ( app5dages1 z %[n to u by fossils1 we f9d !m approa*+ a common po9t4 ,! arm c readily be trac$ to a walk+ app5dage1 :ile ! bird's w+1 by means ( "s int]e/+ connect+ l9ks1 c 9 a simil> way be trac$ to an app5dage ) its five f+]s all free & us$ = walk+4 ,fig4 #di %[s "o ( ^! connect+ l9ks repres5t+ ! e>lie/ type ( bird1 :]e ! f+]s & bones ( ! arm 7 /ill di/9ct1 & yet ! :ole =m$ a true w+4 ,?us we see t ! common po9t ( orig9 :i* is sugge/$ by ! lik5esses betwe5 an arm & a w+ is no m]e imag9>y "o1 = ! fossil record has %[n u ! pa? lead+ to t po9t ( orig94 ,! :ole tells u fur!r t nature's me?od ( produc+ a grasp+ or fly+ organ 0 "h1 n to build a new organ1 b to take "o t _h hi!rto be5 us$ = o!r purposes1 & by sl[ *anges modify its =m & function until x 0 adapt$ to new duties4 ,illu/ration3 ,,fig4 #dg4--,! arm ( a monkey1 a preh5sile app5dage4 ,illu/ration3 ,,fig4 #dh4--,! arm ( a bird1 a fly+ app5dage4 ,9 life cov]$ ) fea!rs4 ,illu/ration3 ,,fig4 #di4--,! arm ( an anci5t half-bird half-reptile animal4 ,9 life cov]$ ) fea!rs & s]v+ z a w+4 ,significance ( ^! ,s\rces ( ,hi/ory4--,! real =ce ( ^! s\rces ( evid5ce comes to u only :5 we comp>e !m ) ea* o!r4 ,!y agree 9 a mo/ rem>kable fa%ion4 ,! hi/ory z disclos$ by fossils & t told by embryology agree ) ea* o!r1 & ^! are 9 close h>mony ) ! hi/ory z x c be read f comp>ative anatomy4 ,if ar*ologi/s 7 to f9d1 9 diff]5t c\ntries & entirely unconnect$ ) ea* o!r two or m diff]5t records ( a lo/ nation1 ! belief 9 ! actual exi/5ce ( t nation w\ld be irresi/ible4 ,:5 rese>*es at ,n9eveh1 = example1 une>? tablets :i* give ! hi/ory ( anci5t nations1 & :5 x proves t among ! nations ?us m5tion$ are "s ) ! same names & hav+ ! same facts ( hi/ory z ^? m5tion$ 9 ! ,bible1 x is absolutely impossible to avoid ! conclusion t su* a nation ) su* a hi/ory did actually exi/4 ,two indep5d5t s\rces ( record c\ld n be false 9 reg>d to su* a matt] z ?is4 ,n[1 our s\rces ( evid5ce = ?is hi/ory ( ! liv+ ma*9e prove to be ( exactly ?is k9d4 ,we h ?ree indep5d5t s\rces ( evid5ce :i* are s entirely diff]5t f ea* o!r t !re is almo/ no lik5ess betwe5 !m4 ,"o is writt5 9 ! rocks1 "o 9 bone & muscle1 :ile ! ?ird is record$ 9 ! evanesc5t & *ang+ pages ( embryology & metamorphosis4 ,yet ea* tells ! same /ory4 ,ea* tells ( a hi/ory ( ?is ma*9e f simple =ms to m complex4 ,ea* tells ( its great] & great] diff]5tiation ( lab\r & /ructure z ! p]iods ( "t pass$4 ,ea* tells ( a gr[+ complexity & an increas+ p]fection ( ! organisms z successive p]iods pass4 ,ea* tells u ( common po9ts ( orig9 & div]g5ce f ^! po9ts4 ,ea* tells u h[ ! m complicat$ =ms h aris5 z ! results ( *anges 9 & modifications ( ! simpl] =ms4 ,ea* %[s u h[ ! individual p>ts ( ! organisms h be5 enl>g$ or dim9i%$ or *ang$ 9 %ape to adapt !m to new duties4 ,ea*1 9 %ort1 tells ! same /ory ( ! gradual con/ruction ( ! liv+ ma*9e by sl[ /eps & ?r\gh long ages ( "t4 ,:5 ^! ?ree s\rces ( hi/ory s accurately agree ) ea* o!r1 x is z impossible to disbelieve 9 ! exi/5ce ( su* hi/ory z x is to disbelieve 9 ! exi/5ce ( ! anci5t ,hittite nation1 aft] its hi/ory has be5 told to u by two diff]5t s\rces ( record4 ,n[ all ?is is v g]mane to our subject4 ,we are try+ to le>n h[ ?is liv+ ma*9e1 ) its wond]ful capabilities1 0 built4 ,! hi/ory :i* we h outl9$ is und\bt$ly ! hi/ory ( ! build+ ( ?is ma*9e1 & ! k t ^! complicat$ ma*9es h be5 produc$ z ! result ( sl[ gr[? is ( ! utmo/ importance to u4 ,?is k gives u at ! v />t "s idea ( ! nature ( ! =ces :i* h be5 at "w4 ,x tells u t 9 se>*+ = ^! =ces we mu/ look = ^? :i* h be5 act+ con/antly4 ,we mu/ look = =ces :i* produce _! effects n by sudd5 additions to ! complication ( ! ma*9e4 ,!y mu/ be con/ant =ces ^: effect at any "o "t is comp>atively slight1 b ^: total effect is to increase ! complexity ( ! ma*9e4 ,!y mu/ be =ces :i* produce new types ?r\gh ! modification ( ! old ones4 ,we mu/ look = =ces :i* d n adapt ! ma*9e = its future1 b only = its pres5t ne$4 ,ea* /ep 9 ! hi/ory has be5 a complete animal ) its own fully develop$ p[]s4 ,we are n to expect to f9d =ces :i* plann$ ! p]fect ma*9e f ! />t1 nor =ces :i* 7 engag$ 9 con/ruct+ p>ts = future use4 ,ea* /ep 9 ! build+ ( ! ma*9e 0 tak5 = ! good ( ! ma*9e at ! p>ticul> mom5t1 & ! =ces :i* we are to look = mu/ !re=e be only su* z c adapt ! organisms = its pres5t ne$s4 ,9 o!r words1 no?+ has be5 produc$ 9 ?is ma*9e = ! purpose ( be+ develop$ lat] into some?+ ( value1 b all p>ts t h be5 produc$ are ( value at ! "t ( _! appe>ance4 ,we mu/1 9 %ort1 look = =ces con/antly 9 action & always t5d+ 9 ! same direction ( great] complexity ( /ructure4 ,is x possible to discov] ^! =ces & compreh5d _! action8 ,be=e ! mod]n developm5t ( evolution ?is "q w\ld unhesitat+ly h be5 answ]$ 9 ! negative4 ,to-day1 "u ! influ5ce ( ! desc5t !ory1 /imulat$1 9 ! fir/ place1 by ,d>w91 ! "q w be answ]$ by _m ) equal promptness 9 ! affirmative4 ,at all ev5ts1 we h le>n$ 9 ! la/ =ty ye>s to recognize "s ( ! factors :i* h be5 at "w 9 ! con/ruction ( ?is ma*9e4 ,we mu/ turn1 !re=e1 to ! consid]ation ( ^! factors4 ,=ces at ,"w 9 ! ,build+ ( ! ,liv+ ,ma*9e4--,!re are ?ree prim>y factors :i* lie at ! bottom ( ! :ole process4 ,!y are-- #a4 ,reproduction1 :i* pres]ves type f g5]ation to g5]ation4 #b4 ,v>iation1 :i* modifies type f g5]ation to g5]ation4 #c4 ,h]$ity1 :i* transmits *>act]s f g5]ation to g5]ation4 ,ea* mu/ be consid]$ by itself4 ,reproduction4--,reproduction is ! prim>y factor 9 ?is process ( ma*9e build+1 h]$ity & v>iation be+ simply phases ( reproduction4 ,! liv+ ma*9e has develop$ by natural processes1 all o!r ma*9es by artificial me?ods4 ,reproduction is ! "o ess5tial po9t ( diff]5ce betwe5 ! liv+ ma*9e & ! o!rs :i* has made _! con/ruction by natural processes a possibility4 ,:at1 !n1 is reproduction8 ,reproduction is 9 all cases at ! bottom simple division4 ,:e!r we consid] ! plant t multiplies by buds or ! unicellul> animal t simply divides into two equal p>ts1 or ! l>g] animal t multiplies by eggs1 we f9d t 9 all cases ! fundam5tal feature ( ! process is division4 ,9 all cases ! organism divides into two or m p>ts1 ea* ( :i* becomes 9 "t l ! orig9al4 ,moreov]1 :5 we trace ?is division fur!r we f9d t 9 all cases x is to be ref]r$ back to ! division ( ! cell1 su* z we h describ$ 9 a previ\s *apt]4 ,! egg is a s+le cell :i* has come f ! p>5t by ! division ( "o ( ! cells 9 ! body ( ! p>5t4 ,a bud is simply a mass ( cells :i* h all aris5 f ! p>5t cells by division4 ,! f\ndation ( reproduction is ?us 9 all cases cell division4 ,n[1 ?is process ( division is dep5d5t ^u ! prop]ties ( ! cell4 ,fir/ly1 x is a result ( ! assimilative p[]s ( ! cell1 = only ?r\gh assimilation c ! cell increase 9 size1 & only z x increases 9 size c x ga9 su/5ance = cell division4 ,secondly1 x is dep5d5t1 z we h se51 ^u ! me*anism ( ! cell body1 & especially ! nucleus & c5trosome4 ,^! /ructures regulate ! cell division1 & h5ce ! reproduction ( all animals & plants4 ,we c n1 !re=e1 f9d any explanation ( reproduction until we h expla9$ ! me*anism ( ! cell4 ,! fundam5tal feature1 ( nature's ma*9e build+ is ?us bas$ ^u ! ma*9]y ( ! nucleus & c5trosome ( ! organic cell4 ,aside f ! simple fact t x pres]ves ! race1 ! mo/ important feature connect$ ) ?is reproduction is its wond]ful fruitfulness4 ,s9ce x results f division1 x always t5ds to increase ! (fspr+ 9 geometrical ratio4 ,9 ! simple/ case1 t ( ! unicellul> animals1 ! cell divides1 giv+ rise to two animals1 ea* ( :i* divides aga91 produc+ f\r1 & ^! aga91 giv+ eight1 etc4 ,! rapidity ( ?is multiplication is sometimes inconceivable4 ,x dep5ds1 ( c\rse1 ^u ! int]val ( "t betwe5 ! successive divisions1 b among ! l[] organisms ?is int]val is sometimes n m ?an half an h\r1 ! result ( :i* is t a s+le individual c\ld give rise 9 ! c\rse ( tw5ty-f\r h\rs to sixte5 million (fspr+4 ,?is is d\btless an extreme case1 b among all ! l[] animals ! rate is v great4 ,among l>g] animals ! process is m complicat$2 b "h1 too1 !re is ! same t5d5cy to geometrical progression1 al?\gh ! int]vals betwe5 ! successive reproductions may be q long & irregul>4 ,b x is always s great t if all[$ to progress unh9d]$ at its normal rate ! (fspr+ w\ld1 9 a few ye>s1 become s num]\s z to cr[d o!r life out ( exi/5ce4 ,ev5 ! sl[-bre$+ elephant w\ld1 if all[$ to bre$ unh9d]$ = sev5 hundr$ & fifty ye>s1 produce n9ete5 million (fspr+--a rate ( increase pla9ly incompatible ) ! cont9u$ exi/5ce ( o!r animals4 ,"h1 !n1 we h ! f\ndation ( nature's me?od ( build+ animals & plants ( ! high] classes4 ,9 ! ma*9]y ( ! cell %e has a p[] ( reproduction :i* produces an increase 9 geometrical ratio f> beyond ! possibility = ! surface ( ! e>? to ma9ta94 ,h]$ity4--,! (fspr+ :i* arise by ^! processes ( division are l ea* o!r1 & l ! p>5t f :i* !y sprung4 ,?is is ! ess5ce ( :at is call$ h]$ity4 ,its significance 9 ! process ( ma*9e build+ is evid5t at once4 ,x is ! cons]v+ =ce :i* pres]ves ! =ms already produc$ & makes x possible = ea* g5]ation to build ^u ! /ructures ( ! e>li] ones4 ,)\t x ea* g5]ation w\ld h to beg9 anew at ! beg9n+1 & no?+ c\ld be accompli%$4 ,b s9ce ?is pr9ciple br+s ea* individual to ! same place :]e its p>5ts /&1 & ?us always builds ! (fspr+ into a ma*9e l ! p>5t1 x makes x possible = ! successive g5]ations to advance4 ,h]$ity is ?us l ! p[] ( memory1 or bett] /ill1 l ! inv5tion ( pr9t+ 9 ! developm5t ( civilization4 ,x is a record ( pa/ a*ievem5ts4 ,by means ( pr9t+ ea* age is enabl$ to b5efit by ! discov]ies ( ! previ\s age1 & )\t x ! developm5t ( civilization w\ld be impossible4 ,9 ! same way h]$ity enables ea* g5]ation to b5efit by ! a*ievem5ts ( its ance/ors 9 ! process ( ma*9e build+1 & ?us to devote its own en]gies to advancem5t4 ,! fact ( h]$ity is pat5t en\gh4 ,x has be5 always cle>ly recogniz$ t ! *ild has ! *>act]s ( its p>5ts1 & ?is belief is s well atte/$ z to ne$ no pro(4 ,x is /ill a "q z to j :at *>act]s may be inh]it$1 & :at influ5ces may affect ! inh]itance4 ,!re are pl5ty ( puzzl+ problems connect$ ) h]$ity1 b ! fact ( h]$ity is "o ( ! f\ndation /ones ( biological sci5ce4 ,^u x mu/ be built all !ories :i* look t[>d ! explanation ( ! orig9 ( ! liv+ ma*9e4 ,?is factor ( h]$ity aga9 we mu/ trace back to ! ma*9]y ( ! cell4 ,we h se5 9 ! previ\s pages evid5ce = ! wond]ful nature ( ! *romosomes ( ! cells4 ,we c n pret5d to und]/& !m1 b !y mu/ be extraord9>ily complex4 ,we h se5 pro( t ^! *romosomes are probably ! physical basis ( h]$ity1 s9ce !y are ! only p>ts ( ea* p>5t :i* are h&$ d[n to subsequ5t g5]ations4 ,) ^! v>i\s facts ( cell division & cell f]tilization 9 m9d1 we c rea* a v simple explanation ( fundam5tal features ( h]$ity4 ,! foll[+ is an outl9e ( ! mo/ widely accept$ view ( ! h]$it>y process4 ,recogniz+ t ! *romosomes are ! physical basis ( h]$it>y transmission1 we c picture to ourselves ! transmission ( h]$it>y *>act]s some?+ z foll[s3 ,z we h se51 ! f]tiliz$ egg conta9s an equal numb] ( *romosomes f ea* p>5t 7,fig4 #db74 ,n[ :5 ?is f]tiliz$ cell divides1 ea* ( ! rods splits l5g?wise1 half ( ea* ent]+ ea* ( ! two cells aris+ f ! cell division4 ,f ?is me?od ( division ( ! *romosomes x foll[s t ! daught] cells w\ld be equival5t to ea* o!r & equival5t also to ! undivid$ egg4 ,if ! orig9al *romosomes conta9$ pot5tially all ! h]$it>y traits h&$ d[n f p>5t to *ild1 ! *romosomes ( ea* daught] cell w conta9 simil> h]$it>y traits4 ,if1 !re=e1 ! orig9al f]tiliz$ egg possess$ ! p[] ( develop+ into an adult l ! p>5t1 ea* ( ! daught] cells %\ld likewise possess ! p[] ( develop+ into a simil> adult4 ,& ?us ea* cell :i* arises z ! result ( su* division %\ld possess simil> *>act]s s long z ?is me?od ( division cont9ues4 ,b aft] a little 9 ! developm5t ( ! egg a diff]5tiation among ! daught] cells arises4 ,!y beg9 to acquire diff]5t %apes & diff]5t functions4 ,?is we c only believe to be ! result ( a diff]5tiation 9 _! *romat9 mat]ial4 ,9 ! cell division ! *romosomes no long] split into equival5t halves1 b "s *>act]s are portion$ (f to "s cells & o!rs to o!r cells4 ,^? cells :i* are to c>ry on dige/ive functions :5 !y are =m$ receive *romat9 mat]ial :i* especially controls !m 9 ! p]=mance ( ?is dige/ive function1 :ile ^? :i* are to produce s5sory organs receive a diff]5t portion ( ! *romat9 mat]ial4 ,?us ! adult individual is built up z ! cells receive diff]5t portions ( ?is h]$it>y sub/ance conta9$ 9 ! orig9al *romosomes4 ,! orig9al *romosomes conta9$ all h]$it>y *>act]s1 b z developm5t proce$s ^! are gradually portion$ out among ! daught] cells until ! adult is =m$4 ,f ?is me?od ( division x w be se5 t ea* cell ( ! adult does n conta9 all ! *>act]s conceal$ 9 ! orig9al *romosomes ( ! egg1 al?\gh ea* conta9s a "p :i* may h be5 d]iv$ f ea* p>5t4 ,x is ?\ght1 h[ev]1 t a "p ( ! orig9al *romat9 mat]ial does n ?us become diff]5tiat$1 b rema9s entirely un*ang$ z ! individual is develop+4 ,?is *romat9 mat]ial may increase 9 am\nt by assimilation1 b x rema9s un*ang$ dur+ ! entire gr[? ( ! individual4 ,x ?us foll[s t ! adult w conta91 along ) its diff]5tiat$ mat]ial1 a c]ta9 am\nt ( ! orig9al physical basis ( h]$ity :i* /ill reta9s its orig9al p[]s4 ,?is undiff]5tiat$ *romat9 mat]ial orig9ally possess$ p[]s ( produc+ a new individual1 & ( c\rse x /ill possesses ^! p[]s1 s9ce x has rema9$ dormant )\t alt]ation4 ,fur!r1 x w foll[ t if ?is dormant undiff]5tiat$ *romat9 %\ld />t into activity & produce a new individual1 ! new individual ?us produc$ w\ld be id5tical 9 all *>act]s ) ! "o :i* actually did develop f ! egg1 s9ce bo? individuals w\ld h come f a bit ( ! same *romat94 ,! *ild w\ld be l ! p>5t4 ,?is w\ld be true no matt] h[ mu* ?is undiff]5tiat$ mat]ial %\ld increase 9 am\nt by assimilation1 s long z x rema9$ unalt]$ 9 "*1 & x h5ce foll[s t e individual c>ries ar\nd a c]ta9 am\nt ( undiff]5tiat$ *romat9 mat]ial 9 all respects id5tical ) t f :i* he develop$4 ,n[ :e!r ?is undiff]5tiat$ g]m plasm1 z we w n[ call x1 is di/ribut$ all ov] ! body1 or is collect$ at c]ta9 po9ts1 is immat]ial to our purpose4 ,x is c]ta9 t portions ( x f9d _! way into ! reproductive organs ( ! animal or plant4 ,?us we see t "p ( ! *romat9 mat]ial 9 ! egg ( ! fir/ g5]ation develops into ! second g5]ation1 :ile ano!r "p ( x rema9s dormant 9 t second g5]ation1 ev5tually becom+ ! *romat9 ( its eggs & sp]matozoa4 ,?us ea* egg ( ! second g5]ation receives *romosomes :i* h come directly f ! fir/ g5]ation1 & ?us x w foll[ t ea* ( ^! eggs w h id5tical prop]ties ) ! egg ( ! fir/ g5]ation4 ,h5ce if "o ( ^! new eggs develops into an adult x w produce an adult exactly l ! second g5]ation1 s9ce x conta9s *romosomes :i* are absolutely id5tical ) ^? f :i* ! second g5]ation sprung4 ,!re is ?us no difficulty 9 und]/&+ :y ! second g5]ation w be l ! fir/1 & s9ce ! process is simply repeat$ aga9 9 ! next reproduction1 ! ?ird g5]ation w be l ! second1 & s on1 g5]ation aft] g5]ation4 ,a /udy ( ! accompany+ diagram w make ?is cle>4 ,9 o!r words1 we h "h a simple und]/&+ ( at lea/ "s ( ! features ( h]$ity4 ,?is explanation is t "s ( ! *romat9 mat]ial or g]m plasm is h&$ d[n f "o g5]ation to ano!r1 & is /or$ tempor>ily 9 ! nucleii ( ! reproductive cells4 ,dur+ ! life ( ! individual ?is g]m plasm is capable ( increas+ 9 am\nt )\t *ang+ its nature1 & x ?us cont9ues to gr[ & is h&$ d[n f g5]ation to g5]ation1 always end[$ ) ! p[] ( develop+ into a new individual "u prop] conditions1 & ( c\rse :5 x does ?us give rise to new individuals !y w all be alike4 ,we c ?us easily und]/& :y a *ild is l its p>5t4 ,x is n because ! *ild c inh]it directly f its p>5t1 b r because bo? *ild & p>5t h come f ! unfold+ ( two bits ( ! same g]m plasm4 ,?is fact ( ! transmission ( ! h]$it>y sub/ance f g5]ation to g5]ation is kn[n z ! !ory ( ! cont9uity ( g]m plasm4 ,su* appe>s to be1 at lea/ 9 "p1 ! ma*9]y ( h]$ity4 ,?is und]/&+ makes ! g]m sub/ance p]petual & cont9u\s1 & expla9s :y successive g5]ations are alike4 ,x does n expla91 inde$1 :y an individual inh]its f its p>5ts1 b :y x is l its p>5ts4 ,:ile biologi/s are /ill 9 dispute ov] _m problems connect$ ) h]$ity1 all are agre$ to-day t ?is pr9ciple ( ! cont9uity ( ! h]$ity sub/ance mu/ be ! basis ( all attempts to und]/& ! ma*9]y ( h]$ity4 ,b pla9ly ?is :ole process is a function ( ! cell ma*9]y4 ,:ile1 !re=e1 ! idea ( ! cont9uity ( g]m sub/ance greatly simplifies our problem1 we mu/ ackn[l$ge t once m we are ?r[n back ^u ! my/]ies ( ! cell4 ,until we c m fully expla9 ! cell ma*9e we mu/ recognize our inability to solve ! fundam5tal "q ( :y an individual is l its p>5ts4 ,illu/ration3 ,,fig4 #ej4--;,diagram illu/rat+ ! pr9ciple ( h]$ity4 ,a repres5ts an egg ( a />fi%4 ,f "o half1 ! un%ad$ portion1 develops ! />fi% ( ! next g5]ation1 ,b4 ,! o!r is di/ribut$ )\t *ange 9 ! ov>ies1 ov1 ( ! individual1 ,b4 ,f ^! ov>ies arises ! next egg1 ,a'1 ) its g]m plasm4 ,?is g]m plasm is evid5tly id5tical ) t 9 ,a1 s9ce x is m]ely a bit ( ! same h&$ d[n ?r\gh ! individual1 ,b4 ,9 ! developm5t ( ! next g5]ation ! process is repeat$1 & h5ce ,b' w be l ,b1 & ! ?ird g5]ation ( eggs id5tical ) ! fir/ & second4 ,! undiff]5tiat$ "p ( ! g]m plasm is ?us simply h&$ on f "o g5]ation to ! next4 ,b pla9ly reproduction & h]$ity1 z we h ?us f> consid]$ !m1 w be unable to acc\nt = ! sl[ modification ( ! ma*9e2 = 9 accordance ) ! facts ?us f> outl9$1 ea* g5]ation w\ld be precisely l ! la/1 & !re w\ld be no *ance = developm5t & *ange f g5]ation to g5]ation4 ,if ! individual is simply ! unfold+ ( ! p[]s possess$ by a bit ( g]m plasm1 & if ?is g]m plasm is simply h&$ on f g5]ation to g5]ation1 ! successive g5]ations mu/ ( necessity be id5tical4 ,b ! liv+ ma*9e has be5 built by *anges 9 ! successive g5]ation1 & h5ce pla9ly "s o!r factor is ne$$4 ,?is factor is v>iation4 ,v>iation4--,v>iation is ! pr9ciple t produces modification ( type4 ,h]$ity1 z j expla9$1 w\ld make all g5]ations alike4 ,b no?+ is m c]ta9 ?an t !y are n alike4 ,! fact ( v>iation is pat5t on e side1 = no two individuals are alike4 ,successive g5]ations diff] f ea* o!r 9 "o respect or ano!r4 ,birds v>y 9 ! l5g? ( _! bills or toes2 butt]flies1 9 _! col\rs2 dogs1 9 _! size & %ape & m>k+s2 & s on ?r\gh an endless category4 ,plants & animals alike ?r\gh\t nature %[ v>iations 9 ! greate/ pr(usion4 ,x is ^! v>iations :i* mu/ furni% u ) ! f\ndation ( ! *anges :i* h gradually built up ! liv+ ma*9e4 ,( ! fact ( ^! v>iations !re is no "q1 & ! matt] ne$ n deta9 u4 ,e "o has _h too _m exp]i5ces to ask = pro(4 ,( ! nature ( ! v>iations1 h[ev]1 !re are "s po9ts to be consid]$ :i* are v g]mane to our subject4 ,9 ! fir/ place1 we mu/ notice t ^! v>iations are ( two k9ds4 ,!re is "o class :i* is born ) ! individual1 s t !y are pres5t f ! "t ( bir?4 ,9 say+ t ^! v>iations are born ) ! individual we d n necess>ily mean t !y are ext]nally app>5t at bir?4 ,a *ild may inh]it f its p>5ts *>act]s :i* d n appe> till adult life4 ,= example1 a *ild may inh]it ! col\r ( its fa!r's hair1 b ?is col\r is n app>5t at bir?4 ,x appe>s only 9 lat] life1 b x is none ! less an inborn "*4 ,9 ! same way1 we may h _m inborn v>iations among individuals :i* d n make !mselves se5 until adult life1 b :i* are none ! less innate4 ,! (fspr+ ( ! same p>5ts may %[ decid$ diff]5ces1 al?\gh !y are put "u simil> conditions1 & su* diff]5ces are ( c\rse inh]5t 9 ! nature ( ! individual4 ,su* v>iations are call$ cong5ital v>iations4 ,!re is1 h[ev]1 a second class ( v>iations :i* are n born 9 ! individual1 b :i* arise z ! result ( "s conditions affect+ its aft]-life4 ,! mo/ extreme in/ances ( ?is k9d are mutilations4 ,"s m5 h only "o leg because ! o!r has be5 lo/ by accid5t4 ,"h is a v>iation acquir$ z ! result ( circum/ances4 ,a blacksmi? diff]s f o!r memb]s ( 8 race 9 hav+ exceptionally l>ge arm muscles2 b "h1 aga91 ! l>ge muscles h be5 produc$ by use4 ,a ,european :o has liv$ "u a tropical sun has a d>k5$ sk91 b ?is sk9 has evid5tly be5 d>k5$ by ! action ( ! sun1 & is q a diff]5t ?+ f ! d>k sk9 ( ! d>k races ( m54 ,9 su* in/ances we h v>iations produc$ 9 individuals z ! result ( outside influ5ces act+ ^u !m4 ,!y are n inborn1 b are second>ily acquir$ by ea* individual4 ,we call !m acquir$ v>iations4 ,x is n always possible to di/+ui% betwe5 ^! two types ( v>iation4 ,frequ5tly a "* w be f\nd 9 reg>d to :i* x is impossible to det]m9e :e!r x is cong5ital or acquir$4 ,if a *ild is born "u ! tropical sun1 h[ c we tell :e!r its d>k sk9 0 ! result ( direct action ( ! sun on its own sk91 or 0 an inh]itance f its d>k-sk9n$ p>5ts8 ,we might suppose t ?is c\ld be answ]$ by tak+ a simil> *ild1 br++ x up away f ! tropical sun1 & see+ :e!r 8 sk9 rema9$ d>k4 ,?is w\ld n suffice1 h[ev]2 = if su* a *ild did !n develop a :ite sk91 we c\ld n tell b t ?is light]-col\r$ sk9 _h be5 produc$ by ! direct blea*+ effect ( ! nor!rn climate ^u a sk9 :i* o!rwise w\ld h be5 d>k4 ,9 o!r words1 a conclusive answ] c n "h be giv54 ,x is n our purpose1 h[ev]1 to attempt to di/+ui% betwe5 ^! two k9ds ( v>iations1 b simply to recognize t !y occur4 ,our next problem mu/ be to se>* = an explanation ( ^! v>iations4 ,) ! acquir$ v>iations we h no p>ticul> tr\ble1 = !y are easily expla9$ z due to ! direct action ( ! environm5t ^u animals4 ,"o ( ! fundam5tal *>act]s ( ! liv+ protoplasm 7us+ ! ^w n[ 9 its wide/ s5se7 is its extreme in/ability4 ,s un/able is x t any di/urb+ influ5ce w affect x4 ,if two simil> unicellul> organisms are plac$ "u diff]5t conditions !y become unlike1 s9ce _! un/able protoplasm is directly affect$ by ! surr\nd+ conditions4 ,) high] animals ! process is naturally a little m complicat$2 b "h1 too1 !y are easily und]/ood z "p ( ! function ( ! ma*9e4 ,"o ( ! adju/m5ts ( ! ma*9e is su* t :5 any organ is us$ m ?an usual ! :ole ma*9e reacts 9 su* a way z to s5d m blood to ?is special organ4 ,! result is a *ange 9 ! nutrition ( ! organ & a correspond+ v>iation 9 ! individual4 ,?us acquir$ v>iations are simply functions ( ! action ( ! ma*9e4 ,cong5ital v>iations1 h[ev]1 c n receive su* an explanation4 ,be+ born ) ! individual1 !y c n be produc$ by conditions affect+ him1 b r to some?+ affect+ ! g]m plasm f :i* he sprung4 ,! nature ( ! g]m plasm controls ! nature ( ! individual1 & cong5ital v>iations mu/ consequ5tly be due to its v>iations4 ,b x is n s easy to see h[ ?is g]m plasm c und]go v>iation4 ,! conditions :i* surr\nd ! individual w\ld affect its body1 b x is n easy to believe t !y w\ld affect ! g]m9al sub/ance4 ,inde$1 x is n easy to see h[ any ext]nal conditions c h influ5ce ^u ?is g]m9al mat]ial if x is n an active "p ( ! body1 b is simply /or$ )9 x = future use 9 reproduction4 ,h[ c\ld any *anges 9 ! environm5t ( ! individual h any effect ^u ?is dormant mat]ial /or$ )9 x8 ,b if we are correct 9 reg>d+ ?is g]m mat]ial 9 ! reproductive bodies z ! basis ( h]$ity & ! guid+ =ce 9 developm5t1 !n x foll[s t ! only way 9 :i* cong5ital v>iations c occur is by "s v>iations 9 ! g]m plasm4 ,if a *ild develop$ f g]m plasm id5tical ) t f :i* its p>5ts develop$1 x w\ld inh]it id5tical *>act]s2 & if !re are any cong5ital v>iations f its p>5ts1 !y mu/ be due to "s v>iations 9 ! g]m plasm4 ,9 o!r words1 9 ord] to expla9 cong5ital v>iations we mu/ acc\nt = v>iations 9 ! g]m plasm4 ,n[1 !re are two me?ods by :i* we may suppose t ^! v>iations 9 ! g]m may arise4 ,! fir/ is by ! direct influ5ce ^u ! g]m plasm ( c]ta9 unkn[n ext]nal conditions4 ,! life sub/ance ( organisms is always v un/able1 &1 z we h se51 acquir$ v>iations are caus$ by ext]nal influ5ces directly affect+ x4 ,n[1 ! h]$it>y mat]ial is also life sub/ance1 & x is pla9ly a possibility = u to imag9e t ?is g]m mat]ial is also subject to influ5ces f ! conditions surr\nd+ x4 ,t su* v>iations d occur appe>s to be h>dly d\btful1 al?\gh we d n "k :at sort ( influ5ces c produce !m4 ,if ! g]m plasm is :olly /or$ )9 ! reproductive gl&1 x is c]ta9ly 9 a position to be only slightly affect$ by surr\nd+ conditions :i* affect ! animal4 ,we c readily und]/& t ! use ( an organ l ! arm w affect x 9 su* a way z to produce *anges 9 its protoplasm1 b we c h>dly imag9e t su* use ( ! arm w\ld produce any *ange 9 ! h]$it>y sub/ance :i* is /or$ 9 ! reproductive organs4 ,ext]nal conditions may ?us readily affect ! body1 b n s readily ! g]m mat]ial4 ,ev5 if su* mat]ial is di/ribut$ m or less ov] ! body in/ead ( be+ conf9$ to ! reproductive gl&s1 z "s believe1 ! difficulty is h>dly less5$4 ,?is difficulty ( und]/&+ h[ ! g]m plasm c be affect$ by ext]nal conditions has l$ "o s*ool ( biologi/s to d5y t x is subject to any v>iation by ext]nal conditions1 & h5ce t all modification ( ! g]m plasm mu/ come f "s o!r s\rce4 ,probably no "o1 h[ev]1 holds ?is position to-day1 & x is ! g5]al belief t ! g]m plasm may be to "s slight ext5t modifi$ by ext]nal conditions4 ,( c\rse1 if su* v>iations d occur 9 ! g]m plasm !y w become cong5ital v>iations ( ! next g5]ation1 s9ce ! next g5]ation is ! unfold+ ( ! g]m plasm4 ,! second me?od by :i* ! v>iations ( g]m plasm may arise is app>5tly ( m importance4 ,x is bas$ ^u ! fact t1 ) all high] animals & plants at lea/1 ea* individual has two p>5ts in/ead ( "o4 ,9 our /udy ( cells we h se5 t ! ma*9]y ( ! cell is su* t x requires 9 ! ord9>y process ( reproduction ! union ( g]m9al mat]ial f two diff]5t individuals to produce a cell :i* c develop into a new individual4 ,z we h se51 ! egg gets rid ( half its *romosomes 9 ord] to receive an equal numb] f a male p>5t2 & ?us ! f]tiliz$ egg conta9s *romosomes1 & h5ce h]$it>y mat]ial1 f two diff]5t individuals4 ,n[1 ?is sexual reproduction occurs v widely 9 ! organic _w4 ,among "s ( ! l[e/ =ms ( unicellul> organisms x is n kn[n1 b 9 mo/ o!rs "s =m ( su* union is univ]sal4 ,n[1 "h is pla9ly an abundant opportunity = cong5ital v>iations2 = x is se5 t ea* individual does n come f g]m mat]ial id5tical ) t f :i* ei!r p>5t came1 b f "s ( ?is mat]ial mix$ ) a simil> am\nt f a diff]5t p>5t4 ,n[1 ! two p>5ts are nev] exactly alike1 & h5ce ! g]m plasm :i* ea* contributes to ! (fspr+ w n be exactly alike4 ,! (fspr+ w ?us be ! result ( ! unfold+ ( a bit ( g]m plasm :i* w be diff]5t f t f :i* ei!r ( its p>5ts develop$1 & ^! diff]5ces w result 9 cong5ital v>iations4 ,sexual reproduction ?us results 9 cong5ital v>iations2 & if cong5ital v>iations are necess>y = ! evolution ( ! liv+ ma*9e--& we %all soon see reason = believ+ t !y are--we f9d t sexual reproduction is a device adopt$ = br++ out su* cong5ital v>iations4 ,inh]itance ( ,v>iations4--,! reason :y cong5ital v>iations are ne$$ = ! evolution ( ! liv+ ma*9e is cle> en\gh4 ,evanesc5t v>iations c h no effect ^u ?is ma*9e1 = !y w\ld disappe> ) ! individual 9 :i* !y appe>$4 ,9 ord] t !y %\ld h any influ5ce 9 ! process ( ma*9e build+ !y mu/ be p]man5t ones2 or1 9 o!r words1 !y mu/ be inh]it$ f g5]ation to g5]ation4 ,only z su* v>iations are transmitt$ by h]$ity c !y be add$ to ! /ructure ( ! develop+ ma*9e4 ,!re=e we mu/ ask :e!r ! v>iations are inh]it$4 ,9 reg>d to ! cong5ital v>iations !re c be no difficulty4 ,! v fact t !y are cong5ital %[s u t !y h be5 produc$ by v>iations 9 ! g]m plasm1 & z su* !y mu/ be transmitt$1 n only to ! next g5]ation1 b to all foll[+ g5]ations1 until ! g]m plasm becomes aga9 modifi$4 ,?is g]m plasm is h&$ on f g5]ation to g5]ation ) all its v>iations1 & h5ce ! v>iations w be add$ p]man5tly to ! ma*9e4 ,cong5ital v>iations are ?us a means = p]man5tly modify+ ! organism1 & by _! ag5cy mu/ we 9 l>ge measure believe t evolution ?r\gh ! ages has tak5 place4 ,) ! acquir$ v>iations ! matt] /&s q diff]5tly4 ,we c readily und]/& h[ influ5ces surr\nd+ an animal may affect its organs4 ,! increase 9 ! size ( ! muscles ( ! blacksmi?'s arm by use we und]/& readily en\gh4 ,b ) our und]/&+ ( ! ma*9]y ( h]$ity we c n see h[ su* an effect c ext5d to ! next g5]ation4 ,x is only ! organ directly affect$ t is modifi$ by ext]nal conditions4 ,acquir$ v>iations w appe> 9 ! "p ( ! body influ5c$ by ! *ang$ conditions4 ,b ! g]m plasm )9 ! reproductive gl&s is n1 s f> z we c see1 subject to ! influ5ce ( an increas$ use1 = example1 9 ! arm muscles4 ,! g]m mat]ial is d]iv$ f ! p>5ts1 &1 if x is simply /or$ 9 ! individual1 h[ c\ld an acquir$ v>iation affect x8 ,if an individual lose a limb 8 (fspr+ w n be )\t a correspond+ limb1 = ! h]$it>y mat]ial is 9 ! reproductive organs1 & x is impossible to believe t ! loss ( ! limb c remove f ! h]$it>y mat]ial 9 ! reproductive gl&s j t "p ( ! g]m plasm :i* 0 design$ = ! production ( ! limb4 ,s1 too1 if ! g]m plasm is simply /or$ 9 ! individual1 x is impossible to conceive any way t x c be affect$ by ! conditions ar\nd ! individual 9 su* a way z to expla9 ! inh]itance ( acquir$ v>iations4 ,if acquir$ v>iations d n affect ! g]m plasm !y _c be inh]it$1 & if ! g]m plasm is only a bit ( protoplasmic sub/ance h&$ d[n f g5]ation to g5]ation1 we c n believe t acquir$ v>iations c influ5ce x4 ,f su* consid]ations z ^! h aris5 two q diff]5t views among biologi/s2 &1 :ile x is n our purpose to deal ) disput$ po9ts1 ^! views are s ess5tial to our subject t !y mu/ be briefly ref]r$ to4 ,"o class ( biologi/s adh]e closely to ! view already outl9$1 & insi/ = ?is reason t acquir$ v>iations c n "u any conditions be inh]it$4 ,!y insi/ t all inh]it$ v>iations are cong5ital1 & due !re=e to direct v>iations 9 ! g]m plasm1 & t all in/ances ( seem+ inh]itance ( acquir$ v>iations are capable ( o!r explanation4 ,! o!r s*ool is equally insi/5t t !re are abundant in/ances ( ! inh]itance ( acquir$ *>act]s1 claim+ t ^! pro(s are s /rong z to dem& _! acceptance4 ,h5ce ?is class ( biologi/s insi/ t ! explanation ( h]$ity giv5 z a simple h&+ d[n f g5]ation to g5]ation ( a g]m plasm is n complete1 & t :ile x is d\btless ! f\ndation ( h]$ity1 x mu/ be modifi$ 9 "s way s z to admit ( ! inh]itance ( acquir$ *>act]s4 ,!re is no "q t has excit$ su* a wide int]e/ 9 ! biological _w dur+ ! la/ fifte5 ye>s z ?is "o ( ! inh]itance ( acquir$ *>act]s4 ,until ab\t #ahhd ! "q 0 n s]i\sly rais$4 ,h]$ity 0 kn[n to be a fact1 & x 0 believ$ t :ile cong5ital *>act]s are m commonly inh]it$1 acquir$ *>act]s may also frequ5tly be h&$ d[n f g5]ation to g5]ation4 ,! facts :i* we h not$ ( ! cont9uity ( g]m plasm h dur+ ! la/ fifte5 ye>s l$ _m biologi/s to d5y ! possibility ( ! latt]4 ,! debate :i* arose has cont9u$ vigor\sly1 & c n be reg>d$ z settl$ at ! pres5t "t4 ,"o result ( ?is debate is cle>4 ,x has be5 %[n beyond "q t :ile ! inh]itance ( cong5ital *>act]s is ! rule1 ! inh]itance ( acquir$ *>act]s is at all ev5ts unusual4 ,at ! pres5t "t _m naturali/s w\ld be incl9$ to ?9k t ! balance ( evid5ce indicates t "u c]ta9 conditions c]ta9 k9ds ( acquir$ *>act]s may be inh]it$1 al?\gh ?is is /ill disput$ by o!rs4 ,into ?is discussion we _c ent] "h4 ,! reason = ref]r+ to x at all is1 h[ev]1 evid5t4 ,we are se>*+ = nature's me?od ( build+ ma*9es4 ,x is p]fectly cle> t v>iations among animals & plants are ! f\ndations ( ! successive /eps 9 advance made 9 ?is ma*9e build+1 b ( c\rse only su* v>iations z c be transmitt$ to po/]ity c s]ve any purpose 9 ?is developm5t4 ,if !re=e x %\ld prove t acquir$ *>act]s c n be inh]it$1 !n we %\ld no long] be able to look ^u ! direct influ5ce ( ! surr\nd+s z a factor 9 ! ma*9e build+4 ,we %\ld !n h no?+ left except ! cong5ital v>iations produc$ by sexual union1 or ! direct v>iation ( ! g]m plasm z a factor = advance4 ,if1 h[ev]1 x %all prove t acquir$ *>act]s may ev5 occasionally be inh]it$1 !n ! direct effect ( ! environm5t ^u ! individual w s]ve z a decid$ assi/ance 9 our problem4 ,"h1 !n1 we h be=e u ! factors :i* h be5 conc]n$ 9 ! build+ ( ! liv+ ma*9e "u nature's h&s4 ,reproduction keeps 9 exi/5ce a con/antly active1 un/able1 readily modifi$ organism z a basis ^u :i* to build4 ,v>iation (f]s con/antly new modifications ( ! type1 :ile h]$ity insures t ! modifications produc$ 9 ! ma*9e by ! influ5ces :i* give rise to ! v>iations %all be p]man5tly fix$4 ,me?od ( ,ma*9e ,build+4--,natural ,selection4 ,! me?od by :i* ^! factors h work$ toge!r to build up ! liv+ ma*9es is easily und]/ood 9 its g5]al aspects1 al?\gh !re are _m details z yet unsolv$4 ,! g5]al facts connect$ ) ! evolution ( animals are matt]s ( common k4 ,we ne$ d no m ?an outl9e ! subject1 s9ce x is well und]/ood by all4 ,! basis ( ! me?od is natural selection1 :i* acts 9 ?is ma*9e build+ some?+ z foll[s3 ,! law ( reproduction1 z we h se51 produces new individuals ) extraord9>y rapidity1 & z a result m individuals are born ?an c possibly f9d su/5ance 9 ! _w4 ,h5ce only a few ( ! (fspr+ ( any animal or plant c live long en\gh to produce (fspr+ 9 turn4 ,! _m mu/ die t ! few may live2 & !re is1 !re=e1 a con/ant /ruggle among ! individuals t are born = food or = room 9 ! _w4 ,9 ?is /ruggle = exi/5ce ( c\rse ! weake/ w g to ! wall1 :ile ^? t are be/ adapt$ = _! place 9 life w be ! ones to get food1 live1 & reproduce _! k9d4 ,?is is at all ev5ts true among ! l[] animals1 al?\gh ) mank9d ! law h>dly applies4 ,n[1 among ! individuals t are born !re w be no two exactly alike1 s9ce v>iations are univ]sal1 _m ( :i* are cong5ital & ?us born ) ! individual & transmitt$ by inh]itance4 ,cle>ly en\gh ^? animals t h a v>iation :i* makes !m a little bett] adapt$ = ! /ruggle w be ! ones to live & h5ce to produce (fspr+1 :ile ^? )\t su* advantage w be ! ones to die4 ,we may suppose1 = example1 t "s ( ! individuals _h long] necks ?an ! av]age4 ,9 "t ( sc>city ( food ^! individuals w\ld be able to get food t ! %ort-neck$ individuals c\ld n rea*4 ,h5ce 9 times ( fam9e ! long-neck$ individuals w\ld be ! ones to survive4 ,n[ if ?is peculi>ity 7 a cong5ital v>iation x w\ld be already repres5t$ 9 ! g]m plasm1 & consequ5tly x w\ld be inh]it$ by ! next g5]ation4 ,! %ort-neck$ individuals be+ l>gely de/roy$ 9 ?is /ruggle = food1 x w\ld foll[ t ! next g5]ation w\ld be a little bett] (f ?an ! la/1 s9ce all w\ld inh]it ?is t5d5cy t[>d a long neck4 ,a few g5]ations w\ld !n see ! disappe>ance ( all individuals :i* did n %[ ei!r ?is or "s o!r correspond+ advantage1 & 9 ?is way ! l5g!n$ neck w\ld be add$ p]man5tly z a "p ( ! ma*9e4 ,:5 ?is "t came ?is peculi>ity w\ld no long] give its possessors any advantage ov] its rivals1 s9ce all w\ld possess x4 ,n[1 !re=e1 "s new v>iation w\ld 9 ! same way det]m9e :i* animals %\ld live & :i* %\ld die 9 ! /ruggle1 & 9 "t a new modification w\ld be add$ to ! ma*9e4 ,& ?us ?is process cont9ues1 "o v>iation aft] ano!r be+ add$1 until ! ma*9e is sl[ly built into a m & m complicat$ /ructure1 always active b ) a con/antly increas+ effici5cy4 ,! con/ruction is a natural "o4 ,a mix+ ( g]m plasm 9 sexual reproduction or "s o!r ag5cies produce cong5ital v>iations2 natural selection act+ ^u ! num]\s prog5y selects ! be/ ( ! new v>iations1 & h]$ity pres]ves & h&s !m d[n to po/]ity4 ,all /ud5ts ( :atev] s*ool recognize ! =ce ( ?is pr9ciple & look ^u natural selection z an effici5t ag5cy 9 ma*9e build+4 ,x is probably ! mo/ fundam5tal ( ! ext]nal laws t h guid$ ! process4 ,!re are1 h[ev]1 c]ta9 o!r laws :i* h play$ a m or less subord9ate "p4 ,! *ief ( ^! are ! influ5ce ( migration & isolation1 & ! direct influ5ce ( ! environm5t4 ,ea* ( ^! laws has its own s*ool ( advocates1 & ea* has be5 giv5 by its advocates ! *ief role 9 ! process ( ma*9e build+4 ,migration & ,isolation4--,! production ( ! v>i\s types ( ma*9es has be5 und\bt$ly facilitat$ by ! migrations ( animals & ! isolation ( diff]5t gr\ps ( desc5dants f ea* o!r by v>i\s natural b>ri]s4 ,! v>iations :i* occur 9 organisms are s great t !y w\ld sometimes run into abnormal /ructures 7 x n = ! fact t sexual reproduction con/antly t5ds to r$uce !m4 ,9 an op5 c\ntry :]e animals & plants int]bre$ freely1 x w commonly happ5 t individuals ) c]ta9 peculi>ities w mate ) o!rs )\t su* peculi>ities1 & ! (fspr+ w !re=e inh]it ! peculi>ity n 9 increas$ degree b 9 decreas$ degree4 ,?is con/ant int]bre$+ ( individuals w t5d to prev5t ! =mation ( _m modifications 9 ! ma*9e :i* become />t$ by v>iations4 ,n[ pla9ly if "s su* individuals1 ) a peculi> v>iation1 %\ld migrate into a new t]ritory or become isolat$ f _! relatives :i* d n h simil> v>iations1 ^! individuals w be oblig$ to bre$ ) ea* o!r4 ,! result w be t ! next g5]ation1 aris+ ?us f two p>5ts ea* ( :i* %[s ! same v>iation1 w %[ x also 9 equal or increas$ degree4 ,migrations & isolations w ?us t5d to fix 9 ! ma*9e v>iations :i* sexual union or o!r influ5ces inaugurate4 ,n[ 9 ! hi/ory ( ! e>?'s surface !re h be5 _m *anges :i* t5d to br+ ab\t su* migration & isolations1 & ?is factor has d\btless play$ a m or less important "p 9 ! build+ ( ! ma*9es4 ,h[ great a "p we _c say1 nor is x necess>y = our purpose to decide2 = 9 all ^! cases ! ma*9e build+ has only be5 ! result ( ! h]$it>y transmission ( cong5ital v>iation "u c]ta9 peculi> conditions4 ,! fundam5tal process is ! same z already consid]$1 only ! details ( its work+ be+ 9 "q4 ,direct ,influ5ce ( ! ,environm5t4--,"u ?is head we h a subject ( great importance4 ,x is an und\bt$ fact t ! environm5t has a v decid$ effect ^u ! ma*9e4 ,^! direct effects ( ! environm5t are v positive & 9 great v>iety4 ,! tropical sun d>k5s ! human sk92 cold climate /unts ! gr[? ( plants2 lack ( food dw>fs all animals & plants1 & hundr$s ( o!r simil> examples c\ld be select$4 ,ano!r class ( simil> influ5ces are ^? produc$ by use & disuse4 ,beyond "q ! use ( an organ t5ds to increase its size1 & disuse to decrease x4 ,combats ( animals ) ea* o!r t5d to increase _! /r5g?1 flight f enemies _! runn+ p[]s1 etc4 ,n[ all ^! effects are direct modifications ( ! ma*9e1 & if !y are only transmitt$ to foll[+ g5]ations s z to become p]man5t modifications1 !y w be mo/ important ag5cies 9 ! ma*9e build+4 ,if1 on ! o!r h&1 !y are n transmitt$ by h]$ity1 !y c h no p]man5t effect4 ,we h "h ?us aga9 ! problem ( ! inh]itance ( acquir$ *>act]s4 ,we h already notic$ ! unc]ta9ty surr\nd+ ?is subject1 b ! almo/ univ]sal belief 9 ! inh]itance ( su* *>act]s requires u to ref] to x aga94 ,x is unc]ta9 :e!r su* direct effects h any influ5ce ^u ! (fspr+1 & !re=e :e!r !y h any?+ to d ) ?is ma*9e build+4 ,/ill1 !re are _m facts :i* po9t /rongly 9 ?is direction4 ,= example1 z we /udy ! hi/ory ( ! horse family we f9d t an orig9ally five-to$ animal began to walk m & m on its middle toe1 9 su* a way t ?is toe receiv$ m & m use1 :ile ! out] toes 7 us$ less & less4 ,n[ t su* a habit w\ld produce an effect ^u ! toes 9 any g5]ation is evid5t2 b app>5tly ?is influ5ce ext5d$ f g5]ation to g5]ation1 =1 z ! hi/ory ( ! animals is foll[$1 x is f\nd t ! out] toes became small] & small] ) ! lapse ( ages1 :ile ! middle "o became correspond+ly l>g]1 until !re 0 f9ally produc$ ! horse ) its "o toe only on ea* foot4 ,n[ "h is a l9e ( desc5t or ma*9e build+ 9 ! direct l9e ( ! effects ( use & disuse1 & x seems v natural to suppose t ! modification has be5 produc$ by ! direct effect ( ! use ( ! organs4 ,!re are _m o!r simil> in/ances :]e ! l9e ( ma*9e build+ has be5 q p>allel to ! effects ( use & disuse4 ,if1 !re=e1 acquir$ *>act]s c be inh]it$ to any ext5t1 we h1 9 ! direct influ5ces ( ! environm5t an important ag5cy 9 ma*9e build+4 ,?is direct effect ( ! conditions is app>5tly s manife/ t "o s*ool ( biologi/s f9ds 9 x ! *ief cause ( ! v>iations :i* occur1 tell+ u t ! conditions surr\nd+ ! organism produce *anges 9 x1 & t ^! v>iations1 be+ h&$ d[n to subsequ5t g5]ations1 con/itute ! basis ( ! developm5t ( ! ma*9e4 ,if ?is factor is entirely exclud$1 we are driv5 back ^u ! natural selection ( cong5ital v>iations z ! only k9d ( v>iations :i* c p]man5tly effect ! modification ( ! ma*9e4 ,consci\sness4--,x may be well "h to ref] to "o o!r factor 9 ! problem1 because x has some:at rec5tly be5 br\ght into prom95ce4 ,?is factor is consci\sness on ! "p ( ! animal4 ,among plants & ! l[] animals ?is factor c h no significance1 b consci\sness c]ta9ly occurs among ! high] animals4 ,j :5 or h[ x appe>$ are que/ions :i* are n answ]$1 & p]haps nev] w be4 ,b consci\sness1 aft] x _h once made its appe>ance1 became a controll+ factor 9 ! developm5t ( ! ma*9e4 ,x mu/ n be und]/ood by ?is t animals h _h any consci\sness ( ! developm5t ( _! body1 or t !y h made any consci\s endeav\rs to modify its developm5t4 ,?is has n always be5 und]/ood4 ,x has be5 frequ5tly suppos$ t ! claim t consci\sness has an influ5ce ^u ! developm5t ( an animal means t ! animal has made consci\s ef=ts to develop 9 c]ta9 directions4 ,= example1 x has be5 sugge/$ t ! tig]1 consci\s ( ! advantage ( be+ /rip$1 _h a desire to possess /ripes1 & ! desire caus$ _! appe>ance4 ,?is is absurd4 ,consci\sness has be5 a factor 9 ! developm5t ( ! ma*9e1 b an indirect "o4 ,consci\sness leads to ef=t1 & ef=t has a direct influ5ce 9 developm5t4 ,= example1 an animal is consci\s ( hung]1 & ?is leads to ef=ts on 8 "p to obta9 food4 ,8 ef=ts to obta9 food may lead to migration or to ! adoption ( new k9ds ( food or to conflicts ) v>i\s k9ds ( rivals1 & all ( ^! ef=ts are pot5t factors 9 det]m9+ ! direction ( developm5t4 ,consci\sness1 aga91 may lead c]ta9 animals to take pleasure 9 ea* o!r's society1 or to recognize t 9 mutual association !y h protection aga9/ common enemies4 ,su* a consci\sness w give rise to social habits1 & social habits are a v pot5t factor 9 det]m9+ ! direction 9 :i* ! inh]it$ v>iations w t5d2 n1 p]haps1 because x effects ! v>iations !mselves1 b r because x det]m9es :i* v>iations among ! _m %all be pres]v$ & :i* reject$ by natural selection4 ,consci\sness may lead ! antelope to recognize t he has no *ance 9 a combat ) a lion1 & ?is w induce him to flee4 ,! habit ( flight w\ld !n develop ! p[] ( flight1 n because ! antelope desir$ su* p[]1 b because ! animals ) v>iations :i* gave increas$ p[] ( flight w\ld be ! ones to escape ! lion1 :ile ! sl[] ones w\ld die )\t (fspr+4 ,?us consci\sness w\ld indirectly1 ?\gh n directly1 result 9 ! l5g!n+ ( ! legs ( ! animal & 9 ! /r5g!n+ ( 8 runn+ muscles4 ,beyond a d\bt ?is factor ( consci\sness has be5 a factor ( no little mom5t 9 ! developm5t ( ! high] types ( organic ma*9es4 ,we c z yet only dimly und]/& its action1 b x mu/ h]eaft] be c\nt$ z "o ( ! influ5ces 9 ! evolution ( ! liv+ ma*9e4 ,b1 aft] all1 ^! are only que/ions ( ! me?od ( ! action ( c]ta9 well demon/rat$1 fundam5tal factors4 ,:e!r by natural selection1 or by ! inh]itance ( acquir$ *>act]s produc$ by ! environm5t1 or :e!r by ! effect ( isolation ( gr\ps ( individuals1 ! ma*9e build+ has always be5 produc$ 9 ! same way4 ,a ma*9e1 ei!r ?r\gh ! direct influ5ce ( ! environm5t1 or z a result ( sexual comb9ation ( g]m plasm1 %[s a v>iation f its p>5ts4 ,?is v>iation proves ( value to its possessor1 :o lives & transmits x p]man5tly to po/]ity4 ,?us /ep by /ep1 "o "p is add$ to ano!r1 until ! ma*9e has gr[n into ! intricately adapt$ /ructure :i* we call ! animal or plant4 ,?is has be5 nature's me?od ( build+ ma*9es1 all bas$ ^u ! ?ree prop]ties possess$ by ! liv+ cell--reproduction1 v>iation1 & h]$ity4 ,summ>y ( ,nature's ,p[] ( ,build+ ,ma*9es4--,let u n[ notice ! position we h rea*$4 ,our problem 9 ! pres5t *apt] has be5 to f9d out :e!r nature possesses =ces adequate to expla9 ! build+ ( ma*9es ) _! p>ts accurately adapt$ to ea* o!r s z to act h>moni\sly = c]ta9 ends4 ,a/ronomy has %[n t %e has =ces = ! build+ ( worlds2 geology1 t %e has =ces = mak+ m\nta9 & valley2 & *emi/ry1 t %e has =ces = build+ *emical comp\nds4 ,b ! organism is nei!r a _w1 nor a mass ( matt]1 nor a *emical comp\nd4 ,x is a ma*9e4 ,has nature any =ces = ma*9e build+8 ,we h f\nd t by ! use ( ! ?ree factors1 reproduction1 v>iation1 & h]$ity1 nature is able to produce a ma*9e ( ev] great] & great] complexity1 ) ! p>ts all adapt$ to ea* o!r4 ,n[ ! diff]5ce betwe5 a ma*9e & a mass ( matt] is simply 9 ! adaptation ( p>ts to act h>moni\sly = def9ite ends4 ,h5ce if we are all[$ ^! ?ree factors1 we c say t nature does possess =ces adequate to ! manufacture ( ma*9es4 ,^! =ces are n *emical =ces1 & ! con/ruction ( ! ma*9e has ?us be5 br\ght ab\t by =ces entirely diff]5t f ^? :i* produc$ ! *emical molecule4 ,b we h pla9ly n rea*$ ! bottom ( ! matt] 9 our attempt to expla9 ! ma*9]y ( liv+ ?+s4 ,we h bas$ ! :ole process ^u ?ree factors4 ,reproduction1 v>iation1 & h]$ity are ! prop]ties ( all liv+ matt]2 b !y are n1 l gravity & *emism1 univ]sal =ces ( nature4 ,!y occur 9 liv+ organisms only4 ,:y %\ld !y occur 9 liv+ organisms1 & "h alone8 ,^! ?ree prop]ties are p]haps ! mo/ m>vell\s prop]ties ( nature2 & surely we h n f9i%$ our task if we h bas$ ! :ole process ( ma*9e build+ ^u ^! my/]i\s ph5om5a1 leav+ !m un9telligible4 ,we mu/ !re=e n[ ask :e!r we c proce$ any f>!r & f9d any explanation ( ^! fundam5tal p[]s ( ! liv+ ma*9e4 ,x mu/ be confess$ t "h we are at pres5t =c$ to /op4 ,we c proce$ no fur!r ) any c]ta9ty1 or ev5 probability4 ,we may say t v>iation & h]$ity are only phases ( reproduction1 & reproduction is a prop]ty ( ! liv+ cell4 ,we may say t ?is p[] ( reproduction is dep5d5t ^u ! p[] ( assimilation & gr[?1 = cell division is a result ( cell gr[?4 ,we may fur!r say t gr[? & assimilation are *emical processes result+ f ! oxidation ( food1 & t ?us all ( ^! processes are to be r$uc$ to *emical =ces4 ,9 ?is way we may seem to h a *emical f\ndation = life ph5om5a4 ,b cle>ly ?is is f> f satisfactory4 ,9 ! fir/ place1 x utt]ly fails to expla9 :y ! liv+ cell has ^! prop]ties1 :ile no o!r body possesses !m1 nor :y !y are possess$ by liv+ protoplasms alone1 ceas+ in/antly ) dea?4 ,inde$ x does n tell u :at dea? c be4 ,secondly1 x utt]ly fails to expla9 ! m>vels ( cell division ) result+ h]$it>y transmission4 ,= all ?is we mu/ fall back ^u ! /ructure ( protoplasm1 & say t ! cell ma*9]y is s adju/$ t ! ma*9e1 :5 act+ z a :ole1 is capable ( trans=m+ ! en]gy ( *emical composition 9 c]ta9 directions4 ,^! fundam5tal prop]ties are !n ! prop]ties ( ! cell ma*9e j z surely z pr9t+ is ! prop]ty ( ! pr9t+ press4 ,we c no m acc\nt = ! life ph5om5a by *emical p[]s ?an we c = pr9t+ by *emical =ces manife/$ 9 ! burn+ ( ! coal 9 ! eng9e room4 ,to be sure1 x is ! *emical =ces 9 ! eng9e room t furni%es ! en]gy1 b x is ! ma*9]y ( ! press t expla9s ! pr9t+4 ,s1 :ile *emical =ces supply life en]gy1 x is ! cell ma*9]y t mu/ expla9 ! fundam5tal liv+ factors4 ,s long z ?is ma*9e is intact x c cont9ue to run & p]=m its duties4 ,b x is a v delicate ma*9e & is easily brok54 ,:5 x is brok5 its activities cease4 ,a brok5 ma*9e c n run4 ,x is dead4 ,9 %ort1 we come back once m to ! idea ( ! ma*9]y ( protoplasm1 & mu/ base our und]/&+ ( its prop]ties ^u its /ructure4 ,x is prop] to /ate t !re are /ill "s biologi/s :o insi/ t ! ultimate explanation ( protoplasm is purely *emical & t life ph5om5a may be manife/$ 9 mixtures ( comp\nds t are purely physical mixtures & n ma*9es4 ,x is claim$ t mu* ( ?is cell /ructure describ$ above is due to imp]fection 9 microscopic me?ods & does n really exi/ 9 liv+ protoplasm1 :ile ! m>vell\s activities describ$ are f\nd only 9 ! highly organiz$ cell1 b d n belong to simple protoplasm4 ,x is claim$ t simple protoplasm consi/s ( a physical mixture ( two diff]5t comp\nds :i* =m a foam :5 ?us mix$1 & t mu* ( ! describ$ /ructure ( protoplasm is only ! appe>ance ( ?is foam4 ,?is conception is c]ta9ly n ! preval5t "o to-day2 & ev5 if x %\ld be ! prop] "o1 x w\ld /ill leave ! cell z an extremely complicat$ ma*9e4 ,"u any view ! cell is a me*anism & mu/ be resolv$ into subord9ate p>ts4 ,x may be unc]ta9 :e!r ^! subord9ate p>ts are to be reg>d$ simply z *emical comp\nds physically mix$1 or z small] units ea* ( :i* is a small] me*anism4 ,at all ev5ts1 at ! pres5t "t we "k ( no su* simple protoplasm capable ( liv+ activities ap>t f ma*9]y1 & ! problem ( expla9+ life1 ev5 9 ! simple/ =m kn[n1 rema9s ! problem ( expla9+ a me*anism4 ,! ,orig9 ( ! ,cell ,ma*9e4--,we h ?us set be=e u ano!r problem1 :i* is aft] all ! fundam5tal "o1 namely1 to ask :e!r we c tell any?+ ( nature's me?od ( build+ ! protoplasmic ma*9e4 ,! build+ ( ! high] animal & plant1 z we h se51 is ! result ( ! p[]s ( protoplasm2 b protoplasm itself is a ma*9e4 ,:at has be5 its hi/ory8 ,we mu/ fir/ notice t no notion ( *emical evolution helps u out4 ,x has be5 a fav\rite ?\ght ) "s t ! orig9 ( ! fir/ liv+ ?+ 0 ! result ( *emical evolution4 ,z ! result ( physical =ces !re 0 produc$1 f ! orig9al nebul\s mass1 a m & m complicat$ sy/em until ! _w 0 =m$4 ,!n *emical ph5om5a became m & m complicat$ until1 ) ! production ( m & m complicat$ comp\nds1 protoplasm 0 f9ally produc$4 ,a few ye>s ago1 "u ! impulse ( ! idea t protoplasm 0 a comp\nd1 or at lea/ a simple mixture ( comp\nds1 ?is ?\ght ( protoplasm z ! result ( *emical evolution 0 q significant4 ,physical =ces1 *emical =ces1 & vital =ces1 expla9 successively ! orig9 ( worlds1 protoplasm1 & organisms4 ,?is conception has1 h[ev]1 no long] mu* significance4 ,we "k ( no su* liv+ *emical comp\nd ap>t f cell ma*9]y4 ,a new conception ( protoplasm has aris5 :i* dem&s a diff]5t explanation ( its orig94 ,s9ce x is a ma*9e r ?an a comp\nd1 me*anical r ?an *emical =ces are requir$ = its explanation4 ,h we !n any sugge/ion z to ! me?od ( ! orig9 ( ?is protoplasmic ma*9e8 ,our answ] mu/1 at ! pres5t1 be c]ta9ly 9 ! negative4 ,! complexity ( ! cell tells u pla9ly t x c n be ! ultimate liv+ sub/ance :i* may h aris5 f *emical evolution4 ,x is made up ( p>ts delicately adapt$ to act 9 h>mony ) ea* o!r1 & its activity dep5ds ^u ! relation ( ^! p>ts4 ,:atev] *emical =ces may h accompli%$1 !y nev] c\ld h comb9$ diff]5t bodies into l991 c5trosomes1 *romosomes1 etc41 :i*1 z we h se51 are ! basis ( cell life4 ,to acc\nt = ?is ma*9e1 !re=e1 we are driv5 to assume ei!r t x 0 produc$ by "s unkn[n intellig5t p[] 9 its pres5t condition ( complex adju/m5t1 or to assume t x has _h a long hi/ory ( build+ by successive /eps1 j z we h se5 to be ! case ) ! high] organisms4 ,! latt] assumption is1 ( c\rse1 9 h>mony ) ! g5]al tr5d ( ?\ght4 ,to-day protoplasm is produc$ only f o!r protoplasm2 b1 pla9ly1 ! fir/ protoplasm on ! e>? mu/ h _h a diff]5t orig94 ,we mu/ !re=e next look = facts :i* w enable u to und]/& its orig94 ,we h se5 t ! animal & plant ma*9es h be5 built up f ! simple cell z ! result ( its p[]s act+ "u ! ord9>y conditions ( nature4 ,n[1 9 accordance ) ?is g5]al l9e ( ?\ght1 we %all be compell$ to assume t previ\s to ! p]iod ( build+ ma*9]y :i* we h be5 consid]+1 !re 0 ano!r p]iod ( ma*9e build+ dur+ :i* ?is cell ma*9e 0 built by c]ta9 natural =ces4 ,b "h we are =c$ to /op1 = no?+ :i* we yet "k gives ev5 a h9t z to ! me?od by :i* ?is ma*9e 0 produc$4 ,we h1 h[ev]1 se5 t !re are =ces 9 nature effici5t 9 build+ ma*9es1 z well z ^? = produc+ *emical comp\nds2 & ?is1 d\btless1 sugge/s to u t !re may be simil> =ces at "w 9 build+ protoplasm4 ,if we c f9d natural =ces by :i* ! simple/ bit ( liv+ matt] c be built up into a complicat$ ma*9e l ! ox1 ) its _m delicately adju/$ p>ts1 x is c]ta9ly natural to imag9e t ! same =ces may h built ?is simpl] ma*9e ) :i* we />t$4 ,b su* a conclusion is = a simple reason impossible4 ,we h se5 t ! ess5tial factor 9 ?is ma*9e build+ is reproduction1 ) ! correlat$ p[]s ( v>iation & h]$ity4 ,)\t ^! =ces we c\ld n h advanc$ 9 ?is ma*9e build+ at all4 ,b ^! prop]ties are !mselves ! result ( ! ma*9]y ( protoplasm4 ,we h no reason = ?9k+ t ?is prop]ty ( reproduction c occur 9 any o!r object 9 nature except ?is protoplasmic ma*9e4 ,( c\rse1 !n1 if reproduction is ! result ( ! /ructure ( protoplasm we c n use ?is factor 9 expla9+ ! orig9 ( ?is protoplasm4 ,! p[]s ( ! complet$ ma*9e c n be br\ght =w>d to acc\nt = its orig94 ,?us ! "o fundam5tal factor = ma*9e build+ is lack+1 & if we are to expla9 nature's me?od ( produc+ protoplasm f simpl] /ructures1 we mu/ ei!r suppose t ! p>ts ( ! cell are capable ( reproduction & subject to h]$ity1 or we mu/ look = "s o!r me?od4 ,su* a road has h[ev] n yet be5 f\nd1 nor h we any idea 9 :at direction to look4 ,b ! fact t nature has me?ods ( ma*9e build+1 z we h se51 may hold out ! possibility t "s day we may discov] h] me?od ( build+ ?is primitive liv+ ma*9e1 ! cell4 ,x is useless to try to g fur!r at pres5t4 ,! orig9 ( liv+ matt] is %r\d$ 9 z great obscurity z ev]4 ,we mu/ admit t ! disclosures ( ! mod]n microscope h complicat$ r ?an simplifi$ ?is problem4 ,:ile a few ye>s ago *emi/s & biologi/s 7 eag]ly expect+ to discov] a me?od ( manufactur+ a bit ( liv+ matt] by artificial means1 t hope has n[ be5 practically ab&on$4 ,! task is app>5tly hopeless4 ,we c manipulate *emical =ces & produce an endless s]ies ( *emical comp\nds4 ,b we c n manipulate ! m9ute bits ( matt] :i* make up ! liv+ ma*9e4 ,s9ce liv+ matt] is made ( ! adju/m5t ( ^! microscopic p>ts ( matt]1 we c n hope to make a bit ( liv+ matt] until we f9d "s way ( mak+ ^! little p>ts & adju/+ !m toge!r4 ,mo/ /ud5ts ( protoplasm h !re=e ab&on$ all expectation ( mak+ ev5 ! simple/ liv+ ?+4 ,we are app>5tly z f> f ! real goal ( a natural explanation ( life z we 7 be=e ! discov]y ( protoplasm4 ,g5]al ,summ>y4--,x is n[ desirable to close ?is discussion ( seem+ly some:at unconnect$ topics by br++ !m toge!r 9 a brief summ>y4 ,?is w enable u to see m cle>ly ! position 9 :i* sci5ce /&s to-day ^u ?is matt] ( ! natural explanation ( liv+ ph5om5a1 & to picture to ourselves m concisely our k ( ! liv+ ma*9e4 ,! problem we h set be=e u is to f9d out to :at ext5t x is possible to acc\nt = vital ph5om5a by ! application ( ord9>y natural laws & =ces1 & !re=e to f9d out :e!r x is necess>y to assume t !re are =ces ne$$ to expla9 life :i* are diff]5t f ^? f\nd 9 o!r realms ( nature1 or :e!r vital =ces are all correlat$ ) physical =ces4 ,x has be5 evid5t at a glance t ! liv+ body is a ma*9e4 ,l o!r ma*9es x consi/s ( p>ts adju/$ to ea* o!r = ! accompli%m5t ( def9ite ends1 & its action dep5ds ^u ! adju/m5t ( its p>ts4 ,l o!r ma*9es1 x nei!r creates nor de/roys en]gy1 b simply conv]ts ! pot5tial en]gy ( its foods into "s =m ( active en]gy1 &1 l o!r ma*9es1 its p[] ceases :5 ! ma*9e is brok54 ,) ?is und]/&+ ! problem cle>ly resolv$ itself into two sep>ate ones4 ,! fir/ 0 to det]m9e to :at ext5t kn[n physical & *emical laws & =ces are adequate to an explanation ( ! v>i\s ph5om5a ( life4 ,! second 0 to det]m9e :e!r !re are any kn[n =ces :i* c furni% a natural explanation ( ! orig9 ( ! liv+ ma*9e4 ,manife/ly1 if ! fir/ ( ^! problems is insolvable1 ! second is insolvable also4 ,9 ! /udy ( ! fir/ problem we h rea*$ ! g5]al conclusion t ! second>y ph5om5a ( life are readily expla9$ by ! application ( physical & *emical =ces act+ 9 ! liv+ ma*9e4 ,^! second>y ph5om5a include su* processes z ! dige/ion & absorption ( food1 circulation1 respiration1 excretion1 bodily motion1 etc4 ,n]v\s ph5om5a also d\btless come "u ?is head1 at lea/ s f> z conc]ns n]v\s =ce4 ,we h be5 oblig$1 h[ev]1 to exclude f ?is correlation ! m5tal ph5om5a4 ,m5tal ph5om5a c n z yet be measur$1 & h n yet be5 %[n to be correlat$ ) physical en]gy4 ,9 o!r words1 x has n yet be5 prov$ t m5tal =ce is en]gy at all2 & if x is n en]gy1 !n ( c\rse x c n be includ$ 9 ! laws :i* gov]n ! physical en]gy ( ! univ]se4 ,al?\gh a close relation exi/s betwe5 physical *anges 9 ! bra9 cells & m5tal ph5om5a1 no fur!r connection has yet be5 drawn betwe5 m5tal p[] & physical =ce4 ,all o!r second>y ph5om5a1 h[ev]1 are intellig5tly expla9$ by ! action ( natural =ces 9 ! ma*9]y ( ! liv+ organism4 ,:ile we h ?us f\nd t ! second>y ph5om5a ( life are intelligible z ! result ( ! /ructure ( ! ma*9e1 c]ta9 o!r fundam5tal ph5om5a h be5 con/antly =c+ !mselves ^u our att5tion z a f\ndation ( ^! second>y activities4 ,! p[] ( contraction1 ! p[] ( caus+ c]ta9 k9ds ( *emical *ange to occur :i* result 9 metabolism1 ! prop]ty ( s5sibility1 ! prop]ty ( reproduction--^! are fundam5tal to all liv+ activity1 & are1 aft] all1 ! real ph5om5a :i* we wi% to expla94 ,b ^! are n peculi> to ! complicat$ ma*9es4 ,we c disc>d all ! app>5t ma*9]y ( ! animal or plant & f9d ^! prop]ties /ill develop$ 9 ! simple/ bit ( liv+ matt]4 ,to le>n _! significance1 !re=e1 we h turn$ to ! /udy ( ! simple/ =m ( matt] 9 :i* ^! fundam5tal prop]ties are manife/$4 ,?is l$ u at once to ! /udy ( ! s-call$ protoplasm1 = protoplasm is ! simple/ kn[n =m ( matt] t is alive4 ,protoplasm itself at fir/ seem$ to be a homog5e\s body1 & 0 look$ ^u z a *emical comp\nd ( high complexity4 ,if ?is 7 true its prop]ties w\ld dep5d ^u its composition & w\ld be expla9$ by ! action ( *emical =ces4 ,su* a conception w\ld h quickly solv$ ! problem1 = x w\ld r$uce liv+ prop]ties to *emical p[]s4 ,b ! conception prov$ to be delusive4 ,protoplasm1 at lea/ ! simple/ =m kn[n to possess ! fundam5tal life prop]ties1 soon %[$ itself to be no *emical comp\nd1 b a ma*9e ( wond]ful intricacy4 ,! fundam5tal ph5om5a ( life & ( protoplasm h prov$ to be bo? *emical & me*anical4 ,metabolism is ! result ( ! oxidation ( food1 & motion is an in/ance ( transf]5ce ( =ce4 ,our problem !n resolv$ itself into f9d+ ! p[] t guides ! action ( ^! natural =ces4 ,food w n und]go su* an oxidation except 9 ! pres5ce ( protoplasm1 nor w ! ph5om5a ( metabolism occur except 9 ! pres5ce ( liv+ protoplasm4 ,cle>ly1 !n1 ! liv+ protoplasm conta9s )9 itself ! p[] ( guid+ ?is play ( *emical =ce 9 su* a way z to give rise to vital ph5om5a1 & our se>* mu/ be n = *emical =ce b = ?is guid+ pr9ciple4 ,our /udy ( protoplasm has told u cle>ly en\gh t we mu/ f9d ?is guid+ pr9ciple 9 ! int]action ( ! ma*9]y )9 ! protoplasm4 ,! microscope has told u pla9ly t ^! fundam5tal pr9ciples are bas$ ^u ma*9]y4 ,! cell division 7reproduction7 is app>5tly controll$ by ! c5trosomes2 ! h]$ity by ! *romosomes2 ! con/ructive metabolism by ! nucleus 9 g5]al1 :ile ! de/ructive metabolism is also seat$ 9 ! cell sub/ance outside ! nucleus4 ,:e!r ^! /atem5ts are /rictly accurate 9 detail does n p>ticul>ly affect ! g5]al conclusion4 ,x is cle>ly en\gh demon/rat$ t ! activities ( ! protoplasmic body are dep5d5t ^u ! relation ( its diff]5t p>ts4 ,al?\gh we h got rid ( ! complicat$ ma*9]y ( ! organism 9 g5]al1 we are /ill confront$ ) ! ma*9]y ( ! cell4 ,b our analysis c n1 at pres5t1 g fur!r4 ,our k ( ?is ma*9e has n z yet enabl$ u to ga9 any insight z to its me?od ( action4 ,we c n yet conceive h[ ?is ma*9e controls ! *emical & physical =ces at its disposal 9 su* a way z to produce ! ord]ly result ( life4 ,! /rict correlation betwe5 ! =ces ( ! physical univ]se & ^? manife/$ by ?is protoplasm tells u t a trans=mation ( en]gy occurs )9 x1 b ( ! me?od ( t trans=mation we z yet "k no?+4 ,irritability1 movem5t1 metabolism1 & reproduction appe> to be n *emical prop]ties ( a comp\nd1 b me*anical prop]ties ( a ma*9e4 ,our me*anical analysis ( ! liv+ ma*9e /ops %ort be=e x rea*es any f\ndation 9 ! *emical =ces ( nature4 ,x is ?us cle>ly app>5t t ! ph5om5a ( life are dep5d5t ^u ! ma*9]y ( liv+ ?+s1 & we h !re=e ! second "q ( ! orig9 ( ?is ma*9]y to answ]4 ,*emical =ces & me*anical =ces h be5 labori\sly inve/igat$1 b nei!r appe> adequate to ! manufacture ( ma*9es4 ,!y produce only *emical comp\nds & worlds ) _! m\nta9s & seas4 ,! con/ruction ( artificial ma*9es has dem&$ intellig5ce4 ,b "h is a natural ma*9e--! organism4 ,x is ! only ma*9e produc$ by natural me?ods1 s f> z we "k2 & we h !re=e next ask$ :e!r !re are1 9 nature1 simple =ces compet5t to build ma*9es su* z liv+ animals & plants8 ,9 pursuance ( ?is "q we h f\nd t ! complicat$ ma*9es h be5 built out ( ! simpl] ones by ! action ( kn[n =ces & laws4 ,! factors 9 ?is ma*9e build+ are simply ^? ( ! fundam5tal vital prop]ties ( ! simple/ protoplasmic ma*9e4 ,reproduction1 h]$ity1 & v>iation1 act+ "u ! ev]-*ang+ conditions ( ! e>?'s surface1 are app>5tly all t are ne$$ to expla9 ! build+ ( ! complex ma*9es out ( ! simpl] ones4 ,nature has =ces adequate to ! build+ ( ma*9es z well z =ces adequate to ! =mation ( *emical comp\nds & worlds4 ,b "h aga9 we are unable to base our explanation ^u *emical & physical =ces4 ,reproduction1 h]$ity1 & v>iation are prop]ties ( ! cell ma*9e1 & we are !re=e ?r[n back ^u ! necessity ( expla9+ ! orig9 ( ?is ma*9e4 ,c we f9d a me*anical or *emical explanation ( ! orig9 ( protoplasm8 ,a *emical explanation ( ! cell is impossible1 s9ce x is n a *emical comp\nd1 b a piece ( me*anism4 ,! explanation giv5 = ! orig9 ( animals & plants is also "h app>5tly impossible4 ,! factors ^u :i* t explanation dep5d$ are factors ( ?is complet$ ma*9e itself1 & c n be us$ to expla9 its orig94 ,we are left at pres5t !re=e )\t any f\ndation = fur!r advance4 ,! cells mu/ h _h a hi/ory ( con/ruction1 b we d n z yet conceive any =ces :i* may be look$ ^u z contribut+ to t hi/ory4 ,:e!r life ph5om5a c be manife/$ by any mixture ( comp\nds simpl] ?an ! cell we d n yet "k4 ,! great problems /ill rema9+ = solution1 :i* h h>dly be5 t\*$ by mod]n biology 9 all its endeav\rs to f9d a me*anical explanation ( ! liv+ ma*9e1 are1 !re=e1 ?ree4 ,fir/1 ! relation ( m5tality to ! g5]al ph5om5a ( ! correlation ( =ce2 second1 ! intelligible und]/&+ ( ! me*anism ( protoplasm :i* enables x to guide ! bl9d *emical & physical =ces ( nature s z to produce def9ite results2 ?ird1 ! k9d ( =ces :i* may h contribut$ to ! orig9 ( t simple/ liv+ ma*9e ^u ^: activities all vital ph5om5a re/--! liv+ cell4 ,,index4 ,a4 ,absorption ( food1 #bj4 ,acquir$ *>act]s1 inh]itance (1 #afd1 #afe1 #aff1 #afg1 #aga4 --v>iations1 #aei1 #afj4 ,amoeba1 #gc4 ,anatomical evid5ce = evolution1 #adb4 ,aquacity1 #hj4 ,arm comp>$ ) w+1 #add4 ,ari/otle1 #a4 ,assimilation1 #hj1 #abd1 #adi1 #agf4 ,a/]s ( divid+ cells1 #ih4 ,b4 ,b>ry1 #fc1 #fd4 ,ba?ybias1 #hd4 ,biology a new sci5ce1 #a1 #e1 #ae4 ,blood1 #ce1 #cf1 #ch1 #fi1 #gc4 ,blood-vessels1 #ce1 #cf4 ,body z a ma*9e1 #bb1 #be1 #di4 ,bone cells1 #fi4 ,build+ ( ! liv+ ma*9e1 #aca1 #acd1 #acf1 #acg1 #afg1 #age1 #ahj4 ,c4 ,c>tilage cells1 #fh4 ,cell z a ma*9e1 #abf1 #abh4 --description (1 #fi4 --division1 #ie1 #if1 #aja4 --discov]y (1 #eh4 --doctr9e1 #fj4 --sub/ance1 #fe1 #abe4 ,cells1 #ef1 #hd1 #hf1 #aah1 #aai4 ,cellul> /ructure ( organisms1 #fe4 ,cell wall1 #fd1 #gb4 ,c5trosome1 #id1 #if1 #ig1 #aja1 #ajc1 #aje1 #aaj4 ,*all5g] exp$ition1 #hc4 ,*emical evolution1 #agi4 ,*emical !ory ( vitality1 #ad2 ( life1 #gh1 #aaf4 ,*emism or me*anism1 #eg1 #agf4 ,*emi/ry ( dige/ion1 #bg1 #bh2 ( protoplasm1 #gf2 ( respiration1 #ch4 ,*romat91 #ib1 #id1 #if1 #ajb1 #adi1 #aec4 ,*romosomes1 #ig1 #ih1 #aja1 #aje1 #ajh1 #aaj1 #aac1 #aeb4 ,circulation1 #cd4 ,colonies ( cells1 #he4 ,comp>ison ( ! body & a ma*9e1 #bb4 ,cong5ital v>iations1 #aeh1 #afj1 #afc2 inh]itance (1 #afd4 ,connective-tissue cells1 #gj4 ,cons]vation ( en]gy1 #g1 #ag4 ,consci\sness z a factor 9 ma*9e build+1 #agc4 ,con/ructive *emical processes1 #ej1 #ea1 #eb1 #abd4 ,cont9uity ( g]m plasm1 #aee4 ,correlation ( vital & physical =ces1 #ac1 #af1 #bb1 #bc1 #bd1 #be4 ,cytobla/ema4 #fb4 ,cytology1 #aj4 ,d4 ,d>w91 #ha4 ,dea? ( ! cell1 #abg4 ,decl9e ( ! reign ( protoplasm1 #he4 ,de/ructive *emical processes1 #ej1 #ea1 #eb1 #abe4 ,dialysis1 #bi1 #cj1 #ca4 ,dige/ion1 #bg4 ,e4 ,egg1 #ajc1 #abj1 #aeb4 division (1 #fc4 ,egg1 f]tilization (1 #ajb4 ,embryological evid5ce = evolution1 #adj4 ,en]gy ( n]v\s impulse1 #dc1 #ed4 ,environm5t1 #aga4 ,evid5ce = evolution z a me?od ( ma*9e build+1 #aci1 #ade4 ,evolution1 #i1 #af1 #ha1 #acd4 ,exp]im5ts ) develop+ eggs1 #aba4 ,f4 ,fat1 absorption (1 #cb4 ,female pronucleus1 #aaj4 ,f]n cells1 section (1 #fg4 ,f]tilization ( ! egg1 #ie1 #ajb2 significance (1 #aab4 ,fibres 9 protoplasm1 #hg2 --9 sp9dle1 #ih1 #aja4 ,=ces at "w 9 ma*9e build+1 #adh1 #agf1 #aha4 ,=m$ mat]ial1 #fd4 ,free cell =mation1 #fd4 ,g4 ,geological evid5ce = evolution1 #aci4 ,g]m plasm1 #aed4 ,h4 ,he>t z a pump1 #ce4 ,heat1 #bd1 #dd1 #de4 ,h]$ity1 #adh1 #aej1 #agf2 --explanation (1 #aeb4 ,h]$it>y traits1 #aac1 #aec4 ,hi/orical geology1 #f4 ,hi/ory ( ! liv+ ma*9e1 #acc1 #adg4 ,horses' toes1 loss (1 #agb4 ,huxley1 #aa1 #ge1 #hc1 #hd4 ,i4 ,irritability1 #ed4 ,isolation1 !ory (1 #agj4 ,k4 ,k>yok9esis1 #if1 #aja4 ,kidneys1 #da4 ,l4 ,leaf1 section (1 #ff4 ,life ! result ( a me*anism1 #aae1 #agg4 ,l991 #ib1 #ajc4 ,l9nu1 #a4 ,lyell1 #f4 ,lymph1 #cf1 #cg4 ,m4 ,ma*9e def9$1 #bj4 ,ma*9es ! result ( me*anical =ces1 #aaf4 ,male cell1 #ajd1 #ajg4 ---- pronucleus1 #aji4 ,maturation ( ! egg1 #ajd4 ,me*anical nature ( liv+ organisms1 #ab4 ,me*anical !ory ( life1 #ha1 #add4 ,membrane ( ! nucleus1 #ib1 #aja4 ,m5tal ph5om5a1 #dg1 #dh4 ,metabolism1 #ed4 ,microsomes1 #hg4 ,migration1 !ory (1 #agj4 ,mon]a1 #hh4 ,movem5t1 #ed4 ,muscle1 #cf1 #ga4 ,n4 ,natural selection1 #afg4 ,n]ve-fibre cell1 #gj4 ,n]v\s en]gy1 #db1 #dd4 ---- sy/em1 #da4 ,new biological problems1 #ae4 ,nucleolus1 #fe1 #ib1 #id4 ,nucleus1 #fe1 #hd1 #hg1 #ic1 #aja1 #ajc1 #aac1 #abd1 #adi2 =mation ( new1 #aja4 ---- function (1 #hi1 #ij1 #ie4 ---- pres5ce (1 #hg1 #hh1 #hi4 ---- /ructure (1 #ia4 ,o4 ,organic *emi/ry1 #gh4 ,organic comp\nds1 artificial manufacture (1 #gh1 #hb4 ,orig9 ( cell ma*9e1 #agh1 #agi1 #ahj4 ,orig9 ( life1 #ha1 #ahb4 ,osmosis1 #bi4 ,oxidation1 #hj1 #agf4 ---- z a vital process1 #ci1 #ef4 ,p4 ,philosophical biology1 #d4 ,physical basis ( life1 #ge4 ,pol> cells1 #ajg4 ,potato1 section ( cells1 #fg4 ,prop]ties ( *emical comp\nds1 #gi4 ,protoplasm1 #ad1 #gd1 #hb1 #hc1 #hd1 #aad1 #aae1 #agi4 ---- artificial manufacture (1 #hb4 ---- z a ma*9e1 #hf1 #agh4 ---- discov]y (1 #gd4 ---- nature (1 #gf4 ---- /ructure (1 #hf1 #hg4 ,purpose vs4 cause1 #aa1 #ab4 ,r4 ,reaction aga9/ ! cell doctr9e1 #aag4 ,reign ( law1 #d4 ---- ( ! nucleus1 #ia4 ---- ( protoplasm1 #ha1 #he4 ,relation%ip1 significance (1 #adc4 ,removal ( wa/e1 #ci1 #dj4 ,reproduction1 #ed1 #hj1 #abd1 #adh1 #agf2 --rapidity (1 #adi4 ,respiration1 #cg4 ,reticulum ( cell1 #hg2 --( nucleus1 #ib4 ,root tip1 section (1 #ff4 ,s4 ,s*ultze1 #gd1 #ge4 ,s*wann1 #fa1 #fb1 #gb4 ,secretion1 #ci1 #dj4 ,segm5tation nucleus1 #aaj4 ,s5sations1 #df4 ,sep>ation ( *romosomes1 #ajj4 ,sexual reproduction1 #ajb4 ,sp]matozoan1 #ajg1 #aji1 #aed4 ,splitt+ ( *romosomes1 #ii4 ,sp9dle fibres1 #aja4 ,/ruggle = exi/5ce1 #afh4 ,summ>y ( ,"p ,i1 #abh4 ---- g5]al1 #ahb4 ,u4 ,undiff]5tiat$ protoplasm1 #hc4 ,unicellul> animals1 #ga4 ,units ( vital activity1 #ec4 ,use & disuse1 #aga1 #agb4 ,v4 ,v>iation1 #adh1 #aeg1 #afj1 #agf4 ,v>iation f sexual union1 #afb4 ,v>iation 9 g]m plasm1 #afa4 ,vegetative functions1 #da4 ,villi1 #ca4 ,vital =ce1 vitality1 #ac1 #ae1 #cd1 #cg1 #eb1 #hj1 #he4 ,vital prop]ties1 #ed2 --locat$ 9 cells1 #abc4 ,w4 ,w+ comp>$ ) arm1 #add4 ,wood cells1 #fh4 ,,! ,,end4 ,,! ,,libr>y ,,( ,,useful ,,/ories4 ,illu/rat$4 #afmo4 ,clo?1 #ce c5ts net p] volume2 po/age1 #d c5ts p] volume additional4 ,! ,/ory ( a ,gra9 ( ,:eat4 ,by ,w4,c4 ,,edg>4 ,! ,/ory ( ,al*emy4 ,by ,m4,m4 ,,pattison ,,muir4 ,! ,/ory ( ,animal ,life4 ,by ,b4 ,,l9dsay4 ,! ,/ory ( ! ,art ( ,music4 ,by ,f4,j4 ,,cr[e/4 ,! ,/ory ( ! ,art ( ,build+4 ,by ,p4,l4 ,,wat]h\se4 ,! ,/ory ( ,k+ ,alfr$4 ,by ,sir ,,walt] ,,besant4 ,! ,/ory ( ,books4 ,by ,,g]trude ,b4 ,,rawl+s4 ,! ,/ory ( ! ,alphabet4 ,by ,,edw>d ,,clodd4 ,! ,/ory ( ,eclipses4 ,by ,g4,f4 ,,*amb]s1 ,f4,r4,a4,s4 ,! ,/ory ( ! ,liv+ ,ma*9e4 ,by ,h4,w4 ,,conn4 ,! ,/ory ( ! ,briti% ,race4 ,by ,,john ,,munro1 ,c4,e4 ,! ,/ory ( ,geographical ,discov]y4 ,by ,,joseph ,,jacobs4 ,! ,/ory ( ! ,cotton ,plant4 ,by ,f4 ,,wilk9son1 ,f4,g4,s4 ,! ,/ory ( ! ,m9d4 ,by ,pr(4 ,j4 ,,m>k ,,baldw94 ,! ,/ory ( ,photography4 ,by ,,alfr$ ,t4 ,,/ory4 ,! ,/ory ( ,life 9 ! ,seas4 ,by ,,sydney ,j4 ,,hickson4 ,! ,/ory ( ,g]m ,life4 ,by ,pr(4 ,h4,w4 ,,conn4 ,! ,/ory ( ! ,e>?'s ,atmosph]e4 ,by ,,d\glas ,,ar*ibald4 ,! ,/ory ( ,ext9ct ,civilizations ( ! ,ea/4 ,by ,,rob]t ,,&]son1 ,m4,a41 ,f4,a4,s4 ,! ,/ory ( ,electricity4 ,by ,,john ,,munro1 ,c4,e4 ,! ,/ory ( a ,piece ( ,coal4 ,by ,e4,a4 ,,m>t91 ,f4,g4,s4 ,! ,/ory ( ! ,sol> ,sy/em4 ,by ,g4,f4 ,,*amb]s1 ,f4,r4,a4,s4 ,! ,/ory ( ! ,e>?4 ,by ,h4,g4 ,,seeley1 ,f4,r4,s4 ,! ,/ory ( ! ,plants4 ,by ,,grant ,,all54 ,! ,/ory ( ,primitive ,man4 ,by ,,edw>d ,,clodd4 ,! ,/ory ( ! ,/>s4 ,by ,g4,f4 ,,*amb]s1 ,f4,r4,a4,s4 ,,o!rs ,,9 ,,prep>ation4 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4 ,,new ,,edition ,,( ,,huxley',s ,,essays4 ,collect$ ,essays4 ,by ,,?omas ,h4 ,,huxley4 ,new complete edition1 ) revisions1 ! ,essays be+ gr\p$ accord+ to g5]al subject4 ,9 n9e volumes1 a new ,introduction accompany+ ea* volume4 #abmo4 ,clo?1 #a4be p] volume4 ,,volume4 ,i4 ,me?ods & ,results4 ,,ii4 ,d>w9iana4 ,,iii4 ,sci5ce & ,education4 ,,iv4 ,sci5ce & ,hebrew ,tradition4 ,v4 ,sci5ce & ,*ri/ian ,tradition4 ,,vi4 ,hume4 ,,vii4 ,man's ,place 9 ,nature4 ,,viii4 ,disc\rses1 ,biological & ,geological4 ,,ix4 ,evolution & ,e?ics1 & ,o!r ,essays4 ,mr4 ,huxley has cov]$ a va/ v>iety ( topics dur+ ! la/ qu>t] ( a c5tury4 ,x gives "o an agreeable surprise to look ov] ! tables ( cont5ts & note ! imm5se t]ritory :i* he has explor$4 ,to read ^! books c>efully & /udi\sly is to become ?or\ghly acqua9t$ ) ! mo/ advanc$ ?\ght on a l>ge numb] ( topics4--,new ,york ,h]ald4 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4 ,d4 ,,appleton ,,& ,,company',s ,,publications4 ,,pione]s ,,( ,,evolution1 f ,?ales to ,huxley ,by ,,edw>d ,,clodd1 ,presid5t ( ! ,folk-,lore ,society2 ,au?or ( ,! ,/ory ( ,creation1 ,! ,/ory ( ',primitive' ,man1 etc4 ,) ,portraits1 #abmo4 ,clo?1 #a4ej4 ,! mass ( int]e/+ mat]ial :i* ,mr4 ,clodd has got toge!r & wov5 into a symmetrical /ory ( ! progress f ignorance & !ory to k & ! intellig5t record+ ( fact is prodigi\s4444 ,! 'goal' to :i* ,mr4 ,clodd leads u 9 s ma/]ly a fa%ion is b ! />t+ po9t ( fre% a*ievem5ts1 &1 9 due c\rse1 fre% !ories4 ,8 book furni%es an important contribution to a lib]al education4--,london ,daily ,*ronicle4 ,we are always glad to meet ,mr4 ,clodd4 ,he is nev] dull2 he is always well in=m$1 & he says :at he has to say ) cle>ness & precision4444 ,! int]e/ int5sifies z ,mr4 ,clodd attempts to %[ ! "p really play$ 9 ! gr[? ( ! doctr9e ( evolution by m5 l ,wallace1 ,d>w91 ,huxley1 & ,sp5c]4444 ,we comm5d ! book to ^? :o want to "k :at evolution really means4--,london ,times4 ,?is is a book :i* 0 ne$$4444 ,altoge!r1 ! book c\ld h>dly be bett] done4 ,x is lum9\s1 lucid1 ord]ly1 & temp]ate4 ,above all1 x is entirely free f p]sonal p>tisan%ip4 ,ea* *ief actor is sympa!tically treat$1 & fri5d%ip is seldom or nev] all[$ to ov]weight s\nd judgm5t--,london ,academy4 ,we c assure ! read] t he w f9d 9 ?is "w a v useful guide to ! lives & labors ( lead+ evolutioni/s ( ! pa/ & pres5t4 ,especially s]viceable is ! acc\nt ( ,mr4 ,h]b]t ,sp5c] & 8 %>e 9 r$iscov]+ evolution1 & illu/rat+ its relations to ! :ole field ( human k4 ,8 =cible /yle & weal? ( metaphor make all t ,mr4 ,clodd writes arre/ive & int]e/+4--,london ,lit]>y ,_w4 ,c n b prove welcome to fair-m9d$ m54444 ,to read x is to h an object-lesson 9 ! mean+ ( evolution4444 ,!re is no bett] book on ! subject = ! g5]al read]4444 ,no "o c\ld g ?r\gh ! book )\t be+ bo? refre%$ & newly in/ruct$ by its ma/]ly survey ( ! gr[? ( ! mo/ p[]ful idea ( mod]n times4--,! ,scotsman4 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4 ,,books ,,on ,,social ,,sci5ce4 ,socialism ,new & ,old4 ,by ,pr(4 ,,william ,,graham1 #abmo4 ,clo?1 #a4ge4 ,pr(essor ,graham's book may be confid5tly recomm5d$ to all :o are int]e/$ 9 ! /udy ( socialism1 & n s intoxicat$ ) its promises ( a new heav5 & a new e>? z to be impati5t ( temp]ate & reason$ criticism4--,london ,times4 ,pr(essor ,graham pres5ts an outl9e ( ! successive s*emes ( ?ree writ]s :o h *iefly influ5c$ ! developm5t ( socialism1 & dwells at l5g? ^u ! sy/em ( ,r\sseau1 t ( ,/4 ,simon1 & on t ( ,k>l ,m>x1 ! f\nd] ( ! new socialism1 ':i* has ga9$ favor ) ! work+ classes 9 all civiliz$ c\ntries1' :i* agrees ) ,r\sseau's plan 9 be+ democratic1 & ) ,/4 ,simon's 9 aim+ at collective own]%ip4444 ,! pr(essor is an indep5d5t ?9k]1 ^: endeavor to be cle> has result$ 9 ! /atem5t ( def9ite conclusions4 ,! book is a rem>kably fair dige/ ( ! subject "u consid]ation4--,philadelphia ,l$g]4 ,dynamic ,sociology3 ,or1 ,appli$ ,social ,sci5ce1 z bas$ ^u ,/atical ,sociology & ! less ,complex ,sci5ces4 ,by ,,le/] ,f4 ,,w>d1 ,a4,m4 ,9 #b vols4 #abmo4 ,clo?1 #d4jj4 ,a book t w amply repay p]usal4444 ,recogniz+ ! dang] 9 :i* sociology is1 ( fall+ into ! class ( dead sci5ces or polite amusem5ts1 ,mr4 ,w>d has und]tak5 to 'po9t out a me?od by :i* ! brea? ( life c be brea!d into its no/rils4'--,ro*e/] ,po/-,express4 ,mr4 ,w>d has evid5tly put great labor & ?\ght into 8 two volumes1 & has produc$ a "w ( int]e/ & importance4 ,he does n limit 8 ef=t to a contribution to ! sci5ce ( sociology4444 ,he believes t sociology has already rea*$ ! po9t at :i* x c be & ought to be appli$1 treat$ z an art1 & he urges t '! ,/ate' or ,gov]nm5t n[ has a new1 legitimate1 & peculi> field = ! ex]cise ( intellig5ce to promote ! welf>e ( m54--,new ,york ,times4 ,crim9al ,sociology4 ,by ,pr(4 ,e4 ,,f]ri4 ,a new volume 9 ! ,crim9ology ,s]ies1 edit$ by ,w4 ,d\glas ,morrison1 #abmo4 ,clo?1 #a4ej4 ,9 ?is volume ,pr(essor ,f]ri1 a di/+ui%$ memb] ( ! ,italian ,p>liam5t1 deals ) ! conditions :i* produce ! crim9al population1 & ) ! me?ods by :i* ?is anti-social section ( ! community may be dim9i%$4 ,he divides ! causes ( crime into two great classes1 individual & social4 ,! individual causes consi/ ( physical & m5tal defects2 ! social causes consi/ ( social disadvantages ( e description4 ,8 view is t ! true rem$y aga9/ crime is to remove individual defects & social disadvantages :]e x is possible to remove !m4 ,he %[s t puni%m5t has comp>atively little effect 9 ?is direction1 & is apt to div]t att5tion f ! true rem$y--! individual & social amelioration ( ! population z a :ole4 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4 ,,books ,,= ,,nature ,,lov]s4 ,insect ,life4 7,new ,edition 9 ,colors47 ,by ,,john ,,h5ry ,,com/ock1 ,pr(essor ( ,entomology 9 ,cornell ,univ]sity4 ,) #ab full-page plates reproduc+ butt]flies & v>i\s insects 9 _! natural colors1 & ) _m wood engrav+s by ,anna ,bots=d ,com/ock1 ,memb] ( ! ,society ( ,am]ican ,wood ,engrav]s1 #abmo4 ,clo?1 #a4ge net2 po/age1 #bj c5ts additional4 ,! volume is admirably writt51 & ! simple & lucid /yle is a con/ant delight4444 ,x is sure to s]ve an excell5t purpose 9 ! direction ( popul> culture1 & ! love ( natural sci5ce :i* x w develop 9 y\?ful m9ds c h>dly fail to be> ri* fruit4--,bo/on ,beacon4 ,famili> ,fi%3 ,_! ,habits & ,capture4 ,a ,practical ,book on ,fre%-,wat] ,game ,fi%4 ,by ,,eug5e ,,mcc>?y4 ,) an ,introduction by ,dr4 ,david ,/>r ,jordan1 ,presid5t ( ,lel& ,/an=d ,junior ,univ]sity1 & num]\s ,illu/rations1 #abmo4 ,clo?1 #a4ej4 ,"o ( ! h&some/1 mo/ practical1 mo/ in=m+ books t we "k4 ,! au?or treats 8 subject ) sci5tific ?or\ghness1 b ) a light t\* t makes ! book easy read+4444 ,! book %\ld be ! companion ( all :o g a-fi%+4--,new ,york ,mail & ,express4 ,! ,art ( ,taxid]my4 ,by ,,john ,,r[ley1 ,*ief ( ! ,dep>tm5t ( ,taxid]my 9 ! ,am]ican ,museum ( ,natural ,hi/ory4 ,illu/rat$1 #abmo4 ,clo?1 #b4jj4 ,mr4 ,r[ley w long be gratefully rememb]$ by taxid]mi/s1 amateurs1 & o!rs1 = ! c>e he has us$ 9 ?us meet+ a long-felt want4--,bangor1 ,me41 ,sportsman4 ,! book is n an elaborate treatise ^u ! ab/ract pr9ciples :i* lie at ! f\ndation ( arti/ic taxid]my1 b is r a comp5dium full ( practical h9ts & sugge/ions1 recipes1 & =mulas = ! work+ taxid]mi/4--,! ,dial4 ,plants4 7,plant ,relations & ,plant ,/ructures 9 "o volume47 ,by ,,john ,m4 ,,c\lt]1 ,a4,m41 ,ph4,d41 ,head ( ,dep>tm5t ( ,botany1 ,univ]sity ( ,*icago1 #abmo4 ,clo?1 #a4hj net4 7,"o ( ! ,tw5tie? ,c5tury ,text-,books47 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4 ,,evolution ,,( ,,man ,,& ,,*ri/ianity4 ,new edition4 ,by ! ,rev4 ,,h[>d ,,macque>y4 ,) a new ,preface1 9 :i* ! ,au?or answ]s 8 ,critics1 & ) "s important ,additions1 #abmo4 ,clo?1 #a4ge4 ,?is is a revis$ & enl>g$ edition ( a book publi%$ la/ ye>4 ,! au?or reviews criticisms ^u ! fir/ edition1 d5ies t he rejects ! doctr9e ( ! inc>nation1 admits 8 d\bts ( ! physical resurrection ( ,*ri/1 & 8 belief 9 evolution4 ,! volume is to be m>k$ z "o ( ! mo/ pr(\nd expressions ( ! mod]n movem5t t[>d broad] !ological positions4--,brooklyn ,times4 ,,hi/ory ,,( ,,! ,,conflict ,,betwe5 ,,religion ,,& ,,sci5ce4 ,by ,dr4 ,,john ,,william ,,drap]4 #abmo4 ,clo?1 #a4ge4 ,! keynote to ?is volume is f\nd 9 ! antagonism betwe5 ! progressive t5d5cies ( ! human m9d & ! pret5sions ( ecclesia/ical au?ority1 z develop$ 9 ! hi/ory ( mod]n sci5ce4 ,no previ\s writ] has treat$ ! subject f ?is po9t ( view1 & ! pres5t monograph w be f\nd to possess no less orig9ality ( conception ?an vigor ( reason+ & weal? ( erudition4--,new ,york ,tribune4 ,a ,,critical ,,hi/ory ,,( ,,free ,,?\ght ,,9 ,,ref]5ce ,,to ,,! ,,*ri/ian ,,religion4 ,by ,rev4 ,canon ,,adam ,,/orey ,,f>r>1 ,d4,d41 ,f4,r4,s41 etc4 #abmo4 ,clo?1 #a4ej4 ,a conflict might naturally be anticipat$ betwe5 ! reason+ faculties ( man & a religion :i* claims ! "r1 on sup]human au?ority1 to impose limits on ! field or mann] ( _! ex]cise4 ,x is ! *ief ( ! movem5ts ( free ?\ght :i* x is my purpose to describe1 9 _! hi/oric succession & _! connection ) intellectual causes4 ,we mu/ asc]ta9 ! facts1 discov] ! causes1 & read ! moral4--,! ,au?or4 ,,creation ,,or ,,evolution8 ,a ,philosophical ,inquiry4 ,by ,,george ,,ticnor ,,curtis4 #abmo4 ,clo?1 #b4jj4 ,a treatise on ! great "q ( ,creation or ,evolution by "o :o is nei!r a naturali/ nor !ologian1 & :o does n pr(ess to br+ to ! discussion a special equipm5t 9 ei!r ( ! sci5ces :i* ! controv]sy arrays aga9/ ea* o!r1 may seem /range at fir/ sight2 b ,mr4 ,curtis w satisfy ! read]1 be=e _m pages h be5 turn$1 t he has a sub/antial contribution to make to ! debate1 & t 8 book is "o to be treat$ ) respect4 ,8 "p is to apply to ! reason+s ( ! m5 ( sci5ce ! rigid scrut9y ) :i* ! lawy] is accu/om$ to te/ ! value & p]t95cy ( te/imony1 & ! legitimacy ( inf]5ces f e/abli%$ facts4--,new ,york ,tribune4 ,d4 ,,appleton ,,& ,,company1 ,,new ,,york4