,,! ,,commonweal? ,,( ,,cells ,"s ,popul> ,essays on ,human ,physiology ,,by ,h4 ,g4 ,f4 ,,spurrell1 ,b4,a4 ,,oxon4 ,illu/ration ,,london ,,bailli,,re1 ,,t9dall ,,& ,,cox #h1 ,,h5rietta ,,/reet1 ,,/r& #aija ,all rights res]v$ ,to ,,my ,,e/eem$ ,,fri5d ,,& ,,tutor1 ,,gu/av ,,mann1 ,m4,d41 ,,etc4 ,,preface ,ev] s9ce ! v beg9n+ ( my /ud5t days1 :5 my contempor>ies took to ply+ me ) emb>rass+ dem&s = in=mation ^u all matt]s m$ical1 ,i h be5 con/antly impress$ by ! int]e/ :i* ! unsci5tific public take 9 ! work+s ( _! bodies & ! mat]ial basis ( _! m9ds4 ,x is ?is g5]al display ( int]e/ among my fri5ds t has embold5$ me to add yet ano!r book to ! _m already deal+ ) ! subject4 ,9 us+ ! ^w #8unsci5tific' ,i imply1 ( c\rse1 no reproa*4 ,i mean simply to d5ote ^? p :o h specializ$ 9 "s bran* ( k o!r ?an ^? collectively kn[n z ,natural ,sci5ce4 ,i usually f9d1 :5 discuss+ physiology ) su* p1 t !y take m int]e/ 9 g5]al pr9ciples ?an 9 details1 :i* !y frequ5tly f9d repell5t1 & t !y frame _! que/ions 9 an appall+ly compreh5sive mann]4 ,my object ?r\gh\t ?is little "w has !re=e be5 to pres5t ! fundam5tal pr9ciples ( physiology 9 a brief1 consecutive & readable =m1 = ^? :o d n c>e to /udy ! text-books4 ,!re is no lack ( excell5t books already1 books illu/rat$ by c>eful draw+s q gruesome 9 _! accuracy1 b !y are almo/ all int5d$ = 8/ud5ts10 & ! casual read]1 f9d+ ! organs divid$ up = exhau/ive treatm5t1 fails to =m a conception ( ! body z an organic :ole1 & misses ! v pr9ciples he is 9 se>* (1 9 ! heap ( details "u :i* !y are buri$4 ,x may cause "s surprise t1 ?\gh 9 my ef=ts to be up-to-date ,i h 9 places out/ripp$ ! text-books1 ,i quote no au?orities4 ,b a mom5t's consid]ation w %[ t x w\ld defeat ! v object ( a sket* l ?is to burd5 ! text ) an acc\nt ( h[ my views 7 =m$1 :ile1 on ! o!r h&1 ! pione]s ( sci5ce w =give me4 ,_! pap]s w be quot$ 9 m durable works1 & _! names hon\r$ long aft] ?is little book has be5 =gott54 ,h4 ,g4 ,f4 ,s4 ,,ox=d1 ,m>*1 #aija4 ,,cont5ts ,,page ,,introduction ix ,,essay ,i4 ,,liv+ ,,matt] #a ,,essay ,,ii4 ,,! ,,*emi/ry ,,( ,,! ,,body #h ,,essay ,,iii4 ,,! ,,me*anics ,,& ,,physics ,,( ,,! ,,body #ca ,,essay ,,iv4 ,,! ,,n]v\s ,,sy/em #eh ,,essay ,v4 ,,! ,,body #id ,,conclusion #ajg ,,index #aac ,,introduction ,! unsci5tific public is extremely prone1 & n altoge!r )\t reason1 to take m$ic9e z a />t+-po9t1 & arrange all biological sci5ce ar\nd x4 ,z x is1 moreov]1 apt to gauge ! int]e/ & utility ( e bran* ( ?is sci5ce f a practical po9t ( view1 & be/[s mo/ att5tion ^u t :i* x imag9es is ( ! greate/ s]vice to ! doctor1 ,i ?9k a s]ies ( popul> essays on physiology c\ld n comm5ce ) m advantage1 at any rate to physiology1 ?an by briefly discuss+1 n ) :at x deals1 = t is pretty g5]ally kn[n1 b :at is its relation to m$ic9e4 ,fur!r1 z ! doctor is m easily discuss$ ?an m$ic9e1 ! physiologi/ w be m manageable = our imm$iate purpose ?an physiology 9 ! ab/ract1 s we w devote ! fir/ few pages to ! "q ( h[ 8 lab\rs b5efit ! pati5t4 ,ev]yone kn[s ! doctor1 & ev]yone kn[s t physiology deals ) ! #8functions ( diff]5t organs ( ! body'2 b ! public r>ely meet ! physiologi/1 except 9 ! fanciful c>icatures ( 8 enemies1 :i* ?\gh frequ5tly p]sonal are r>ely accurate4 ,^! rancor\s libels1 if anyone he$$ !m1 w\ld t5d to raise d\bts z to :e!r ! physiologi/ 0 a good companion = ! doctor1 & if x 7 n z well = !m to see z little ( ea* o!r z possible4 ,! doctor1 h[ev]1 _c move a /ep )\t ! physiologi/4 ,8 bus9ess is to correct ! revolt ( any organ f its allott$ task1 & repair ! damage done by its deviation f ! normal pa?4 ,?is he _c possibly d if he does n "k :at t organ's normal conditions are1 & :at !y are x is ! physiologi/'s duty to tell him4 ,a doctor1 !re=e1 %\ld be an enlight5$ physiologi/1 kn[+ h[ ! body ought to "w1 & ref]r+ diseases to _! real cause1 su* z ! poisons =m$ by an invasion ( bact]ia or o!rwise1 or wrong fe$+--t is to say1 defici5cy or excess ( fuel = "o ( ! body's _m eng9es4 ,m$ic9e is /ill to a l>ge ext5t rule ( ?umb4 ,we don't "k to :at _m diseases are due1 or :y c]ta9 ?+s relieve !m1 if any rem$y is kn[n2 & until ^! que/ions are satisfactorily settl$1 x is va9 to hope t disease z a :ole c be successfully combat$4 ,x is no use kn[+ :at w /op c]ta9 unpleasant symptoms if we d n "k h[ to remove _! real cause1 & = ?is end ! :ole body & e individual compon5t organ is be+ /udi$1 t ! process ( life may be accurately und]/ood2 & ! man :o is do+ ?is = 8 fri5d ! doctor is ! physiologi/4 ,! physiologi/ has _m enemies1 a motley array ( cranks held toge!r by su* noble bonds z g5]al hatr$ ( sci5ce & prejudic$ ignorance masqu]ad+ z scepticism2 b he c af=d to ignore !m1 = ! v good reason t p _c get on )\t him4 ,x is only on acc\nt ( ?is t !y are m5tion$4 ,p say1 #8,! doctor is ! p]son :o requires a k ( physiology2 he is ! man :o is mo/ likely to /udy x successfully'--presumably by 8 mi/akes--#8& n wa/e m "t on x ?an is necess>y1' a po9t ab\t :i* !y are mo/ solicit\s4 ,! doctor1 h[ev]1 pref]s to tru/ ! physiologi/4 ,if he did n1 he w\ld h v little "t to d any?+ else4 ,y might z well expect a tailor to make 8 own clo? be=e he makes a coat4 ,he w d\btless be able to make bett] coats if ! quality ( ! clo? suppli$ him is improv$2 b if 9 ord] to improve ! f9i%$ article he lays d[n 8 scissors & applies 8 f+]s to weav+1 8 bus9ess w be sure to suff]4 ,t physiology is a ?+ :i* c take up a man's :ole en]gies w1 ,i ?9k1 be admitt$ by anyone :o realizes h[ wide is its scope4 ,! physiologi/ himself mu/ specialize1 = ! subject is too va/ = "o man to und]take ! :ole4 ,! body is compos$ ( ! same elem5ts z ! re/ ( ! _w1 & _! arrangem5t is v important1 s he mu/ be a pr(ici5t *emi/4 ,x is compos$ ( solids1 liquids & gases1 & diffusion1 filtration1 lev]age1 are frequ5t processes1 & e motion is accompani$ by an electric manife/ation1 s t me*anics & physics mu/ h be5 "p ( 8 tra9+4 ,he c sc>cely /udy organs if he does n "k _! %ape1 s he %\ld "k "s anatomy4 ,&1 la/ly1 z 8 bus9ess is to /udy life & all its att5dant ph5om5a--& ! basis ( life is ! cell--he mu/ be a hi/ologi/4 ,to be all ^! ?+s is a great deal to require ( "o man2 b ?\gh he may specialize = ! advancem5t ( a p>ticul> bran* ( 8 sci5ce1 he mu/ be au fait ) ! re/1 z no vital function is dep5d5t ^u "o alone ( ! factors enum]at$4 ,h>d "w is requir$ ( him1 ?\gh "s p say he has done b little4 ,:at he has discov]$ is briefly1 v briefly1 set =? 9 ! ensu+ essays1 ) a h9t or two at ! knots he w\ld l & is try+ n[ to unravel4 ,,! ,,commonweal? ,,( ,,cells4 ,"s ,popul> ,essays on ,human ,physiology4 ,,essay ,i4 ,,liv+ ,,matt]4 ,physiology is ! /udy ( life1 & ! ?+ ( all o!rs :i* ! physiologi/ w\ld l to discov] is :at life really is4 ,if ?is 7 fully kn[n1 all physiological processes c\ld probably be d$uc$ f x1 & disease1 :i* is an int]f]5ce ) "o or o!r ( !m1 c\ld be sci5tifically treat$4 ,s f> he has n got beyond describ+ ! consequ5ces ( life1 & 8 d$uctions c>ry him no fur!r ?an ?is3 life is a prop]ty ( a sub/ance1 protoplasm1 & protoplasm c only cont9ue to exi/ 9 ! =m ( a cell4 ,?is def9ition may seem a little cryptic to "s p1 & v %ock+ to o!rs4 #8,life1' _m p are accu/om$ to say1 #8means ! pres5ce ( a s\l1 & is sup]natural2 & z to its be+ a "q ( *emical composition1 t is absurd4 ,my be+ made ( cells1 too1 w n acc\nt = my ?9k+4' ,b :5 p dogmatize ?us ab\t :at !y h n consid]$1 !y usually f9d !mselves l&$ 9 difficulties4 ,!y g s fa/3 ! mo/ spiritual ( m5 is s dep5d5t ^u matt] & its prop]ties t 8 s\l w spe$ily quit 8 body if he is prev5t$ f brea?+4 ,& ! reason ( ?is is1 t if he _c get air1 ! *emi/ry ( ! cells ( :i* 8 body is made becomes alt]$2 he no long] consi/s ( protoplasm1 !re=e he no long] lives4 ,life1 t x may exi/ 9 a mat]ial _w1 mu/ h a mat]ial basis1 & if t is int]f]$ ) x becomes ext9ct or quits ! mat]ial plane2 9 any case1 ceases to int]e/ ! physiologi/ z a physiologi/4 ,i d n ?9k anyone ne$ be %ock$ at ?is be+ recognis$4 ,x is1 ( c\rse1 ! ambition ( ! physiologi/ to make protoplasm1 b s f> he has got no fur!r ?an mak+ "s ( ! complicat$ bodies into :i* protoplasm breaks up :5 x dies4 ,a little :ile ago ?is b>e possibility 0 l\dly d]id$1 b ! advance 9 organic *emi/ry has be5 s great ( late ye>s1 & s _m complicat$ sub/ances :i* once seem$ z unobta9able z protoplasm itself h be5 made 9 ! laboratory1 t we n[ h hope ( a precise k ( ! *emi/ry ( life "s day1 ?\gh t day may be yet v di/ant4 ,to give an acc\nt ( life is to describe z f> z we are able ! nature ( ! liv+ sub/ance1 protoplasm2 & z protoplasm is a #8/ructure ( comp\nds1' a ^w or two ab\t *emical comp\nds may cle> ! gr\nd = discuss+ x4 ,if y 7 to take a comp\nd1 say a lump ( sug>1 & />t break+ x up1 y c\ld hamm] = a v long "t & x w\ld be /ill sug>2 b if a t9y fairy ) a m9ute hamm] & *isel 7 to g on break+ up ! gra9s1 he w\ld ultimately h molecules ( sug> be=e him4 ,ea* molecule w\ld consi/ ( exactly ! same numb] ( atoms ( c>bon1 hydrog5 & oxyg51 & if he divid$ x fur!r by ! removal ( a s+le atom1 x w\ld no long] be sug>4 ,he c\ld hamm] away at ! atoms z h>d z he lik$1 = !y are incapable ( fur!r division4 ,!re are sev5ty odd diff]5t k9ds ( atoms4 ,:5 ! molecules ( a sub/ance are compos$ ( only "o k9d1 x is said to be simple2 :5 ( sev]al k9ds1 comp\nd4 ,n[1 ! diff]5ce betwe5 ! v>i\s sub/ances we see ar\nd u consi/s n only 9 :at diff]5t k9ds ( atoms _! molecules are compos$ ( & _! numb]1 b 9 _! arrangem5t4 ,?is arrangem5t may be 9 *a9s or r+s1 & ! relative position :i* ! diff]5t atoms occupy 9 ! /ructure ( a molecule makes all ! diff]5ce 9 ! _w4 ,?is diff]5ce ( composition gives ! diff]5ce ( prop]ties to comp\nds2 s a comp\nd mu/ consi/ only ( molecules :i* are all alike4 ,if a sub/ance is made up ( molecules ( diff]5t k9ds1 ununit$ by *emical bonds1 & !re=e capable ( be+ mix$ 9 any proportions1 x is call$1 n a comp\nd1 b a mixture ( comp\nds4 ,b j z atoms comb9e to =m molecules1 s ! small] molecules sometimes ent] into comb9ations ) "o ano!r to =m new comp\nds hav+ l>g] & m complex molecules4 ,su* a comp\nd is said to be compos$ ( radicles1 or gr\ps ( atoms1 & on be+ decompos$ c be brok5 up1 fir/ into simpl] comp\nds1 :i* c aft]w>ds be fur!r divid$ into _! con/itu5t elem5ts4 ,n[1 ( all sub/ances1 protoplasm seems to consi/ ( ! l>ge/ numb] ( compon5ts1 & to h !m arrang$ 9 ! mo/ complicat$ way kn[n2 ?\gh #8kn[n' is really n ! "r ^w to use 9 ?is connection4 ,! reason :y we d n "k :at life is1 is t we _c f9d out 9 :at way ! con/itu5t comp\nds 9 ! protoplasmic /ructure are comb9$4 ,directly we try to analyze protoplasm1 x dies2 t is1 x splits up into a numb] ( simpl] bodies & is alt]$ beyond recon/ruction4 ,^! comp\nds into :i* protoplasm breaks up :5 x dies are !mselves extremely complex2 b ?\gh mu* c>eful /udy has be5 be/[$ ^u !m1 we _c z yet say h[ !y are put toge!r to =m ! liv+ sub/ance4 ,protoplasm is too v>iable a body to be consid]$ a s+le comp\nd1 :ile1 on ! o!r h&1 ! *emical relation%ips ( its compon5ts mu/ be too close to admit ( its be+ call$ a mixture4 ,its *emical position is !re=e unique1 & we c only speak ( x z a sub/ance ( unkn[n composition4 ,:at1 !n1 is x t makes protoplasm unmi/akable & diff]5t to all o!r sub/ances8 ,! complexity ( its /ructure is1 aft] all1 m]ely a matt] ( degree4 ,! diff]5ce is n easily def9$1 b x r\ghly am\nts to ?is3 ,protoplasm is always *ang+1 yet always rema9s ! same4 ,life is ! *ange 9 ! molecules4 ,if our def9ition ( life seem$ obscure1 ?is s\nds l a p>adox2 b p]haps ! foll[+ fact may help to expla9 x3 ,"u c]ta9 conditions "s ( ! simpl] comp\nds behave 9 a some:at simil> way4 ,= in/ance1 !re is "o :i* is s gre$y ( oxyg5 t x grabs x f :atev] w readily give x up1 & 9 ord] to d s is oblig$ to rel9qui% t :i* x has already got 9 its molecule to make room = t fre%ly acquir$4 ,protoplasm is always behav+ 9 ?is sort ( way z long z x is protect$ f extremes ( heat & cold1 & f active *emicals :i* split up its molecules to =m fre% comp\nds4 ,!n x dies1 or ceases to be protoplasm4 ,b ! importance ( ?is con/ant *ange lies 9 ! fact t by cont9ually break+ d[n its own molecules protoplasm obta9s ! en]gy to rebuild !m out ( non-liv+ comp\nds ( high pot5tial en]gy1 to modify its environm5t1 &1 9 fact1 to d ! "w ( life4 ,x 0 said above t protoplasm only cont9u$ to exi/ 9 ! =m ( a cell2 !re=e1 :at is a cell1 & :y its necessity8 ,we h se5 t protoplasm has a v complicat$ /ructure1 & t its normal condition is "o ( *ange4 ,?is be+ s1 x obvi\sly _c exi/ 9 l>ge masses1 = if x did ! *ange w\ld be sure to be unev5 9 diff]5t p>ts f its v complexity2 & ! c5tre ( ! lump w\ld ei!r be />v$ or poison$ by ! products ( its own life4 ,to avoid ?is1 ! mass is divid$ up into a va/ numb] ( small units ea* complete 9 itself1 9 communication m or less direct ) its neighb\rs1 & all equally accessible to fluids :i* bo? fe$ & cleanse !m4 ,b !re is ano!r & /ill m important reason = su* a division4 ,! protoplasm is con/antly dis*>g+ decomposition products1 & ne$s to be repair+ its wa/e by build+ 9 fre% comp\nds4 ,! raw mat]ial ar\nd x requires dress+ be=e x c be ( use1 & ! build+ 9 is a difficult bus9ess4 ,9 ea* cell !re is1 !re=e1 a place set ap>t1 :]e ! protoplasm has peculi> capabilities1 & x is "h t ?is elaboration is c>ri$ out4 ,?is spot is call$ ! nucleus4 ,?us x w be se5 t ! =mation ( an animal's body by ! aggregation ( cells is a necess>y & +5i\s way ( avoid+ a difficulty4 ,to say1 h[ev]1 t an animal's body consi/s ( cells is to take an entirely wrong />t+-po9t4 ,a cell is complete 9 itself1 & c live if prop]ly f$1 ev5 ?\gh sep>at$ f its neighb\rs4 ,_m :ole animals consi/ ( only "o cell4 ,a cell is1 moreov]1 capable ( gr[+ & divid+1 ?us giv+ rise to two cells ) two nuclei1 & x is only because cells f9d t x pays bett] n to sep>ate1 b to =m masses & specialize at diff]5t k9ds ( "w1 t we h l>ge animals compos$ ( millions ( cells l ourselves4 ,giv5 a cell1 x is necess>y to keep t cell "u fav\rable conditions4 ,o!rwise ! un/able protoplasm breaks up4 ,x mu/ h ! elem5ts necess>y to keep up its cycle ( *anges 9 ! prop] =m1 :i* we may n[ call food1 & _m cells h to g & f9d ?is requisite4 ,x mu/ keep away f injuri\s influ5ces1 & x mu/ race o!r cells = localities fav\rable to its gr[? & multiplication2 9 fact1 ! cell mu/ "w4 ,t a cell c1 9 virtue ( its *emical aff9ities alone1 move ab\t1 seek+ fav\rable conditions1 %[+ discrim9ation & do+ "w1 seems incompreh5sible4 ,9 ! fir/ place1 h[ c x move8 ,!re is only "o way3 x mu/ effect a r$i/ribution ( its sub/ance1 & contrive t ^? p>ts ( ! cell ^: activity is appli$ to ?is end %all be s situat$ z to produce def9ite *anges 9 its %ape accord+ to ! cause :i* evokes !m4 ,( ! way 9 :i* diff]5t cells move we %all h a good deal m to say lat]4 ,:y protoplasm %\ld be influ5c$ to move /ill requires explanation4 ,yet ! gap betwe5 protoplasm & o!r sub/ances is really n s great1 aft] all4 ,heat & magnetism cause movem5t 9 inanimate matt]1 & ! response ( protoplasm z exemplifi$ by "s ( ! m9ute unicellul> animals is almo/ z me*anical4 ,"s k9ds :i* swim 9 wat] move to ! positive pole ( a galvanic batt]y1 o!rs to ! negative1 if ! wires are dipp$ into ! vessel conta9+ !m4 ,"s move t[>ds light1 o!rs away f x1 ) unv>y+ regul>ity4 ,temp]ature & *emical sub/ances also cause a def9ite effect ^u ^! micro-organisms4 ,& all ^! movem5ts are :olly involunt>y1 absolutely inv>iable1 &1 9 fact1 reactions evok$ by fix$ causes4 ,nev]!less1 x w be se5 t protoplasm c only cont9ue to exi/ 9 ! =m ( a cell1 s9ce1 unless ?us organiz$1 x c nei!r keep itself among fav\rable surr\nd+s nor prep>e fre% +r$i5ts to make good its wa/e4 ,if a cell be cut up into sev]al pieces1 ^! deta*$ bits ( protoplasm w live = a "t2 b dea? ov]takes !m z soon z !y h us$ up _! res]ve mat]ial4 ,:5 ?is is gone1 !y h to consume _! own sub/ance1 a process :i* quickly proves fatal4 ,%\ld a fragm5t conta9 a small "p ( ! nucleus cut away ) x1 x w live a little long]2 b x is only ! piece :i* conta9s ! nucleus m or less intact--9 o!r words1 ! cell1 damag$ ?\gh x be--:i* c survive & recov] f su* mutilation4 ,! specialization ( protoplasm to =m a cell is p]haps its mo/ rem>kable peculi>ity4 ,n only is protoplasm diff]5tiat$ to =m diff]5t /ructures1 b x devotes ! en]gy evolv$ 9 its ceaseless *ange to diff]5t purposes4 ,! protoplasm ( ! motor organs ( ! cell exp5ds itself :olly 9 produc+ ! physical movem5ts necess>y to approa* & capture food4 ,:5 ?is has be5 pass$ into ! cell1 protoplasm ( ano!r v>iety works to ref9e & dissolve x1 & !n passes x on to ! nucleus4 ,! protoplasm ( ! nucleus1 aga91 has diff]5t "w to d4 ,x devotes its en]gy to produc+ *emical *anges 9 ! raw mat]ial1 & conv]t+ x into new comp\nds :i* ! v>i\s p>ts ( ! cell c assimilate4 ,"s ( ^! x reta9s = its own ne$s2 ! re/ x disp5ses to ! motor & o!r organs to repair _! wa/e1 & supply !m ) en]gy to obta9 m food4 ,?us d ! diff]5t v>ieties ( protoplasm :i* compose a cell supply "o ano!r's ne$s1 & enable "o ano!r to live2 & ?us does a cycle ( *emical *anges =m ! f\ndation ^u :i* ! :ole fabric ( life re/s4 ,b into details we _c yet g1 = our inve/igations ( ! mat]ial basis ( life h n yet c>ri$ u beyond ^! g5]al conclusions4 ,at pres5t we "k no?+ def9ite ab\t ! fir/ causes ( life1 &1 ?\gh we h hopes1 p]haps we nev] %all4 ,mean:ile we are obs]v+1 analyz+1 & classify+ ! ph5om5a 9 :i* life is manife/$1 9 ! hope t at la/ light may break ?r\gh ^u our rese>*es1 & we may be able1 if n to syn!sise protoplasm 9 a te/-tube1 at lea/ to demon/rate its work+s 9 equations4 ,9 ! meantime1 our actual k ( liv+ matt] c /ill be compress$ into ! words 9 :i* ,pr(essor ,huxley summ$ x up ye>s ago3 #8,c>bon1 hydrog51 oxyg51 & nitrog5 are all lifeless bodies4 ,( ^!1 c>bon & oxyg5 unite1 9 c]ta9 proportions & "u c]ta9 conditions1 to give rise to c>bonic acid2 hydrog5 & oxyg5 produce wat]2 nitrog5 & hydrog5 give rise to ammonia4 ,^! new comp\nds1 l ! elem5t>y bodies ( :i* !y are compos$1 are lifeless4 ,b :5 !y are br\ght toge!r "u c]ta9 conditions !y give rise to ! /ill m complex body1 protoplasm1 & ?is protoplasm exhibits ! ph5om5a ( life4' ,until we h fur!r k ( ! *anges :i* con/itute ^! ph5om5a1 physiology mu/ rema9 descriptive r ?an explanatory4 ,,essay ,,ii4 ,,! ,,*emi/ry ,,( ,,! ,,body4 ,i4 ,! cell is usually v m9ute--inde$1 absolutely invisible )\t a microscope1 ?\gh 9 "s cases x is a fair size4 ,! :ole yolk ( an egg is a s+le cell until its m9ute nucleus1 a speck on "o side1 />ts divid+ & x becomes sev]al4 ,by ! "t ! *ick is ready to be hat*$ !re are millions4 ,usually1 h[ev]1 a cell is small--j z mu* protoplasm z its /ill m m9ute nucleus c keep go+2 ?\gh "h1 aga91 "o mu/ be gu>d$1 = !re may be sev]al nuclei in/ead ( only "o4 ,! protoplasm on ! ext]nal surface & ar\nd ! nucleus is specializ$ into a m or less def9ite membrane4 ,to ?is out] envelope are atta*$ f9e fibrils1 :i* jo9 up to a small body )9 ! cell1 call$ ! c5trosome1 & by ! l5g!n+ & %ort5+ ( ^! its %ape c be alt]$4 ,! cont5ts are fluids2 s if ! conta9+ membrane is loos5$ 9 any direction1 !y t5d to bulge out & =m an excresc5ce1 & 9 ?is way ! cell is enabl$ to ?r[ out limbs & surr\nd p>ticles ( food1 &1 by relax+ ! fibrils 9 "o direction & contract+ !m 9 o!rs1 to crawl :i!r its *emical1 !rmal1 or physical aff9ities direct4 7,see ,diagram #a47 ,n p>ticul>ly inspir+ is ! sight ( life 9 its simple/ =m1 b :5 a few millions ( ^! cells gr\p toge!r & =m "o body1 divid+ ! lab\r betwe5 !m1 ! result is some?+ /up5d\s4 ,!re are animals compos$ 9 ?is way1 "s ( ^: cells h develop$ _! dige/ive capabilities to su* an ext5t t !y h almo/ lo/ all _! o!rs4 ,^! are c>efully gu>d$ 9 ! int]ior ( ! body4 ,o!r cells 9 ?is same bea/1 receiv+ _! food 9 a fluid =m f ^! dige/ive speciali/s1 secrete lime ar\nd !m till a skeleton is built up4 ,to ! lev]s ( ?is skeleton are atta*$ bundles & /r&s ( cells1 :i*1 if !y c d no?+ else1 c l5g!n & %ort5 & make x move4 ,yet1 aga91 !re are cells :i* h especial facilities = receiv+1 weigh+1 & transmitt+ *emical & physical prompt+s4 ,^! cells1 aga91 lie 9 a protect$ corn] ( ! int]ior1 b !y s5d out f9e ?reads to "o ano!r & e "p ( ! body1 & control ! :ole4 ,! animal 9 :i* ?is beautiful sy/em ( division ( lab\r has be5 c>ri$ to its greate/ p]fection has _m & v>i$ p[]s4 ,he c 9 "s cases ev5 apply to ! individuals ( ! species ! pr9ciples ( 8 own cellul> economy1 & !reby a*ieve n only ! mak+ ( poetry & jokes1 b ! build+ ( a ,we/m9/] ,abbey1 ! con/ruction ( ,maxim guns1 & ! en=c+ ( 8 economic ref9em5ts ^u 8 less highly specializ$ neighb\rs4 ,we h n[ trac$ out a g5]al idea ( life4 ,we h se5 t its basis re/s ^u a *emical /ructure :i*1 to ma9ta9 its id5tity1 mu/ be always *ang+4 ,we h se5 t to d ?is x mu/ keep break+ d[n its sub/ance1 & giv+ (f ! products1 & tak+ hold ( extrane\s mat]ials1 & build+ !m 91 n only to repair ! loss1 b 9 ord] to gr[2 & t to d t x has to be m or less modifi$ 9 p>ts1 9 ord] t ! ma9 bulk may be br\ght )9 rea* ( its food1 & be !n able to conv]t x into ! mo/ useful =m4 ,&1 la/ly1 we h se5 t j z sev]al specializ$ =ms ( plasm toge!r make up a cell1 s sev]al k9ds ( cells1 ea* ) "s peculi>ity exagg]at$1 aggregate1 &1 supply+ "o ano!r's ne$s1 compose a body4 ,hav+ n[ r\ghly sket*$ out ! s*eme ^u :i* su* a body works1 we c g on to a m detail$ exam9ation ( ! division ( ! lab\r1 & ! way 9 :i* ea* dep>tm5t supplies1 & is dep5d5t ^u1 ! o!rs4 ,if we 7 to d ?is ?or\ghly1 x w\ld take a great deal ( "t & space1 = ! physiology ( a potato plant1 ?\gh ess5tially ! same1 pres5ts _m diff]5ces f t ( a horse2 b ! physiology ( ! great human int]e/ is also t ( ! mo/ complicat$ animal1 namely1 man1 s x is on him t we %all focus our att5tion4 ,protoplasm is m easily /udi$ ! m specializ$ is ! animal x composes4 ,:5 all ! ev5ts ( life are tak+ place 9 a speck ( matt]1 invisible )\t a microscope1 x is impossible to analyze ! *anges :i* x is work+ 9 its surr\nd+s1 or to inf] ^? :i* are go+ on 9 itself4 ,b :5 l>ge numb]s ( cells are exam9$ collectively1 we c deal ) :at !y take 9 & :at !y give out 9 suffici5t bulk to arrive at a fairly accurate det]m9ation4 ,! /udy is r5d]$ /ill easi] 9 an animal ) extremely specializ$ organs1 l man1 9 :i* food is ne>ly all tak5 9 by ! m\?1 & ?us kept q di/9ct f :at is elim9at$2 ! latt]1 aga91 be+ mo/ly giv5 (f by ! kidneys is kept equally di/9ct4 ,moreov]1 ! int]m$iate *anges be+ p]=m$ 9 diff]5t organs /ill fur!r simplifies inve/igation ( ! vital process2 = ! physical effects are also m easily /udi$ :5 exagg]at$ 9 a p>ticul> "p ( ! animal4 ,! electrical *anges 9 a s+le cell might long h rema9$ unsuspect$ _h we n be5 able to obs]ve ^? 9 a muscle ) ! galvanomet]4 ,n[1 :ile ! cells :i* make up ! body ( man diff] v greatly ow+ to ! diff]5t tasks :i* !y h to p]=m 9 obta9+ food & gett+ rid ( refuse1 !y all require v mu* ! same fuel to enable !m to live1 & hav+ got x1 !y all treat x 9 v mu* ! same way2 !re=e our fir/ bus9ess is to consid] :at ! body wants1 & :at x does ) x4 ,aft]w>ds we c try to f9d out h[ x gets x1 & :]e4 ,! fir/ & mo/ indisp5sable requirem5t ( protoplasm is wat]4 ,! next is probably nitrog51 comp\nds ( :i* seem to =m ! framework ( ! protoplasmic /ructure4 ,! next is probably c>bon1 & ! next free oxyg54 ,! two la/-m5tion$ comb9e ) a release ( en]gy4 ,?is happ5s 9 ! grate :5 coal burns1 & ! result is heat4 ,9 ! tissues ( a body ! result may be heat1 gr[?1 or movem5t1 all ?ree be+ pres5t 9 ! ph5om5on ( muscul> activity4 ,f9ally !re are m9]al salts1 ! mo/ important be+ sodium *loride1 :i* is plac$ on ! table at e civiliz$ meal4 ,b ?\gh ^! elem5ts are giv5 "h 9 ord]1 _! importance is really equal1 = all are necess>y4 ,t is ab\t z mu* z x is wise to say "h4 ,! *emi/ry ( ! liv+ cells--_! anabolism1 or h[ fre% mat]ial is built into _! /ructure2 _! katabolism1 or h[ ! same /ructure is brok5 d[n t "w may be done2 9 fact1 ! g5]al metabolism--is s complicat$1 & s little und]/ood z yet1 & requires s ext5sive a k ( *emi/ry to foll[1 t x is be/ left alone by p :o d n want to g into x deeply4 ,at be/1 su* a discussion resolves itself into an exposition ( diff]5t obs]v]s' !ories1 ) ! reasons :y !y hold !m--reasons bas$ on labori\s & te*nical /udies4 ,pages might be writt5 on ! v>i\s !ories1 back$ by pages m ( *emical =mul1 to %[ :y ?is view des]ves deep consid]ation1 :ile t1 9 spite ( ! ob/9acy ) :i* x is upheld1 is absurd2 b ?\gh su* discussions take "o ne>e/ ! secret ( life1 ! g5]al public is n unnaturally apt to /igmatize ?is side ( physiology z dry4 ,x is a matt] :i* int]e/s exp]ts1 n ! casual read]4 ,q a diff]5t affair is ! "q ( diet4 ,t is ev]ybody's bus9ess1 z ! numb] ( faddi/ societies & blatantly adv]tis$ #8foods' atte/4 ,& ?\gh ! prep>ation ( ! food 9 ! body up to ! po9t :]e x m]ges into liv+ matt] & is lo/ sight (--9 a ^w1 #8dige/ion'--is aga9 a "q ( *emi/ry1 x is "o :i* may be approa*$ )\t su* an exhau/ive k ( t sci5ce z ! previ\s consid]ations w\ld h requir$4 ,x is1 moreov]1 to judge f ! way x is discuss$1 a topic ( univ]sal int]e/4 ,a casual glance at ! animal k+dom w %[ t diet is a wide subject4 ,a pigeon w eat peas2 a tig] w\ld n "k :at to d ) ! peas if he got !m2 :ile a monkey w eat almo/ any?+ he c lay h&s on4 ,a plant takes u /ill fur!r afield1 = x c use ! atoms ( sub/ances ) an extremely simple molecule--c>bonic acid gas1 = in/ance4 ,our task1 h[ev]1 is simplifi$ by our hav+ only man to consid]2 & al?\gh mo/ ( ! high] animals are s mu* alike t !y might be consid]$ 9 g5]al & contra/$ 9 detail1 x is a great ?+ to get rid ( ! :ole vegetable k+dom ) bact]ia & p>asitic animals4 ,"o ( ! fir/ requisites = ! ma9t5ance ( life1 z 0 m5tion$ above1 is nitrog54 ,n[1 nitrog5 is "o ( ! commone/ elem5ts 9 ! _w1 b x is ! h>de/ to supply to ! body4 ,f\r-fif?s ( ! air is pure nitrog51 b pure nitrog5 is useless z a food4 ,we draw x into our lungs at e brea?1 & are none ! bett] = x1 = we brea! x out aga9 un*ang$2 & if x 7 completely abs5t f ! air we %\ld n be s v mu* ! worse4 ,! ,anci5t ,m>9] exclaim$1 #8,wat]1 wat] ev]y:]e1 & n a drop to dr9k'2 a />v+ man might exclaim1 #8,nitrog51 nitrog5 ev]y:]e1 & n an atom to assimilate4' ,animals h to get _! nitrog5 9 ! =m ( proteid1 a sub/ance ^: molecule is compos$ ( nitrog51 oxyg51 hydrog51 c>bon1 etc41 & might r\ghly be describ$ z dead protoplasm4 ,plants on :i* animals fe$1 :5 !y d n get _! proteid by ! simpl]1 ?\gh less moral1 me?od ( eat+ "o ano!r1 are able to get _! nitrog5 9 a simpl] =m2 b ) t we are n conc]n$4 ,! proteids are a gr\p ( sub/ances :i* resemble protoplasm 9 ! elem5ts ( :i* !y are compos$ & 9 ! complexity ) :i* !y are comb9$4 ,! v>i\s proteids seem1 h[ev]1 to h a def9ite *emical composition1 & !re=e diff] f protoplasm 9 be+ true comp\nds2 moreov]1 if kept f bact]ia !y und]go no *anges4 ,"o ( ! be/ =ms ( proteid = exam9ation is :ite ( egg2 ?is1 z is kn[n1 sets or coagulates :5 boil$1 dissolves 9 wat]1 f :i* x may be precipitat$ by boil+1 & displays v>i\s o!r *emical prop]ties common to all proteids4 ,!re is1 h[ev]1 a good deal ( diff]5ce betwe5 ! sev]al v>ieties ( proteids1 & ! m complex ones h to be conv]t$ into ! simpl] be=e !y c be absorb$4 ,h5ce ! necessity = dige/ion4 ,n[1 z proteid resembles dead protoplasm1 x might be suppos$ t a diet ( proteid alone w\ld be ! mo/ economical2 b ?is is n s4 ,if x 7 possible to live )\t "w1 i4e41 )\t movem5t ( any k9d1 x might be2 b to d "w1 m c>bon mu/ be oxidiz$ ?an ! proteid molecule conta9s4 ,c>bon1 ! next item on our li/1 is famili> to ev]yone 9 ! comp>atively pure =m ( coal1 *>coal1 & ! #8lead' ( p5cils4 ,x is commonly us$ to burn--i4e41 oxidize--t heat may be obta9$ to boil wat] & to "w ma*9]y4 ,?is is precisely :at x is requir$ to d 9 ! body1 :]e x is burnt by oxyg5 tak5 9 by ! lungs1 t heat & en]gy may result4 ,x is a commonplace t sev]e ex]cise causes lab\r$ brea?+1 & ! reason ( ?is is t ! c>bon 9 ! body is be+ oxidiz$1 & ! product1 c>bonic acid gas1 has to be got rid (4 ,! m "w is be+ done1 ! m oxyg5 is requir$ to burn c>bon 9 ! muscles4 ,! m c>bon is burnt1 ! m heat is evolv$1 & ! m necess>y x is t ! blood %\ld be cool$ by draw+ cool air into ! lungs4 ,h5ce ! m rapid brea?+4 ,! air normally brea!d out is always w>m] ?an t tak5 91 & always conta9s extra c>bonic acid gas4 ,aft] ex]cise ! quantity is increas$1 & its increase on ! normal am\nt giv5 (f c readily be demon/rat$ by analyz+ samples ( ! air tak5 9 & giv5 out4 ,b c>bon1 l nitrog51 _c be tak5 9 9 ! crude =m4 ,no "o w\ld try to make a meal ( *>coal4 ,a c]ta9 am\nt is conta9$ 9 ! proteid molecule1 en\gh1 no d\bt1 to secure ! basis ( ! protoplasmic /ructure2 b unless "o is prep>$ to eat an excessive quantity ( proteid1 a proce$+ entail+ wa/e & exhau/ion ( ! dige/ive app>atus1 ! balance mu/ be made up by eat+ c>bohydrate4 ,! =ms 9 :i* p are mo/ famili> ) c>bohydrate are />* & sug>4 ,sug> is ! bett] food1 z x is s mu* m soluble ?an />*2 &1 9 fact1 />* is always turn$ into a k9d ( sug> be=e x is us$ by ! body4 ,! common cane-sug>1 :i* ev]yone kn[s s well1 is ab\t ! mo/ useful food we h1 ow+ to its purity1 & !re=e conc5tration1 & its simplicity4 ,a v small am\nt ( dige/ion is necess>y to conv]t x into ! simple/ ( all c>bohydrates1 a sub/ance easily /or$1 z glycog51 till want$1 :i* is pres5t 9 muscle aft] a meal1 & is us$ up :5 ! muscle is active1 be+ oxidiz$ to c>bonic acid gas1 s>colactic acid1 & alcohol4 ,! importance ( c>bon 9 ! diet is !re=e obvi\s2 & p :o int5d do+ extra muscul> "w %\ld take extra sug>y food r ?an extra proteid4 ,a locomotive :i* is ab\t to make a record run takes 9 m coal1 n m eng9e-driv]s1 & our a?letes n[ foll[ ! same pr9ciple4 ,we %all1 h[ev]1 h a good deal m to say ab\t a?letes pres5tly4 ,!re is yet ano!r po9t to be consid]$ 9 respect to c>bon4 ,c>bon ne$ n be tak5 9 ! =m ( c>bohydrate1 ! alt]native be+ fats & oils4 ,fats & c>bohydrates are bo? compos$ ( ! elem5ts c>bon1 hydrog51 & oxyg51 b ! proportions 9 :i* !y are jo9$ are diff]5t4 ,fats are n su* useful foods z c>bohydrates1 nor to mo/ p s pleasant--comp>e a spoonful ( olive-oil & a lump ( sug>4 ,b !re is "o important po9t to be urg$ 9 _! fav\r3 !y yield twice z mu* heat z ei!r proteids or c>bohydrates2 s _! position among foods is assur$4 ,! o!r *emical necessities ( ! body we ne$ only m5tion "h4 ,hydrog5 is "o ( ! compon5ts ( proteid1 c>bohydrate1 fat1 & wat]2 & if x does n ent] 9 ! la/ =m1 x--at any rate1 mo/ ( x--leaves z su*1 be+ oxidiz$ 9 ! tissues4 ,sulphur & iron des]ve hon\rable m5tion2 common salt is requir$ by ! blood2 lime & phosphates g to make bone2 b important z !y all are1 !y ne$ n deta9 u fur!r at pres5t4 ,) reg>d to ! am\nt ( ^! elem5ts :i* is requir$ p] day1 & :i* is asc]ta9$ by collect+ & weigh+ all t is giv5 (f1 x is f\nd t ab\t ounce ( nitrog5 & #aj ounces ( c>bon are necess>y to an av]age man--i4e41 weigh+ ab\t #aj /one4 ,! ounce ( nitrog5 & ab\t #b ounces ( ! c>bon are conta9$ 9 #d ounces ( dry proteid1 :i* leaves a balance ( #h ounces ( c>bon to be made up2 & ?is is usually obta9$ by eat+ #d ounces ( fat & #ah ounces ( c>bohydrate4 ,r\ghly speak+1 ^! pr9ciples are conta9$ 9 p\nd ( ord9>y but*]'s meat & #b p\nds ( bread2 b x w\ld be well to def] consid]+ diet = ! pres5t1 until we h exam9$ ! app>atus by :i* ! body extracts :at x wants f ! raw mat]ials1 & :i* ( ^! (f] x ! lea/ resi/ance4 ,,ii4 ,! way 9 :i* protoplasm gets its *emical requisites = gr[? is d\btless simply by absorb+ !m4 ,"s ( ! l[] /ructureless =ms c>ry ?is to an absurd extreme1 = :5 two individuals meet !y fuse1 & ea* no d\bt claims to h eat5 ! o!r4 ,z1 moreov]1 ! fir/ ?+ :i* a cell does :5 x gr[s is to divide1 ! :ole proce$+ looks r futile4 ,b ready-made protoplasm ( an assimilable %ape is r>e1 & x is n (t5 t a cell1 unless x be a plant or a p>asite1 f9ds itself 9 a sub/ance :i* c be h&$ /raight to ! nucleus )\t fur!r elaboration4 ,usually ! cell has to dis*>ge f itself a reag5t1 :i* w develop ! "r *emical qualities 9 ! matt] x wants to absorb4 ,?is sub/ance is kn[n z an enzyme1 or f]m5t4 ,f]m5ts1 h[ev]1 are an exp5se to ! cell1 requir+ a c]ta9 ef=t = _! production2 s1 9 ord] t !y may be economiz$1 !y are1 9 ! high] =ms1 p\r$ ov] ! food :ile x is 9 an enclos$ cavity1 or /oma*4 ,9 ! simple/ animals1 consi/+ ( a s+le cell1 ! protoplasm simply fl[s r\nd ! p>ticle ( food1 & x is #8+e/$' ) a drop ( wat]4 ,into ?is #8food vacuole' ! f]m5ts are secret$1 & :5 all t is useful has be5 dissolv$ out & absorb$1 ! bubble moves to ! surface & bur/s2 or1 to put x diff]5tly1 ! cell fl[s on its way1 & ! vacuole1 ) any %ell or refuse x may conta91 gets left beh9d4 7,see ,diagram #a47 ,9 o!r cells :i* are con/ant 9 %ape !re is an op5+ lead+ to ! int]ior ( ! cell4 ,r\nd ?is !re are little project+ ?reads1 :i* beat ! wat] regul>ly4 ,9 "s positions ^! ?reads enable ! cell to swim1 b "h _! duty is to cause a curr5t & wa% p>ticles ( food d[n ! primitive ?roat into ! int]ior1 :]e1 z 9 ! prec$+ case1 !y become enclos$ 9 a vacuole4 7,see ,diagram #b47 ,illu/ration3 ,,diagram #a4--,,! ,,am,,ba4 ,illu/ration3 ,,diagram #b4--,,p>am,,cium4 ,mov+ a /age high]1 we f9d animals consi/+ ( sev]al cells4 ,( ^! x is only natural to suppose t "s h great] enzyme-=m+ p[]s ?an o!rs4 ,illu/ration3 ,,diagram #c4--;,,developm5t ,,( ,,an ,,embryo3 ,,fir/ ,,/age4 ,illu/ration3 ,,diagram #d4--;,,=mation ,,( ,a ,,dige/ive ,,cavity4 ,illu/ration3 ,,diagram #e4--;,,cross ,,section ,,( ,a ,,develop+ ,,embryo4 ,a /ep high] 9 ! animal scale1 or a fur!r advance 9 ! developm5t ( ! s*ematic embryo 7depict$ 9 ,diagrams #c to #f71 & we f9d t ^! special dige/ive cells are los+ _! /urdi] qualities & be+ plac$ 9 a position protect$ by cells :i* h specializ$ 9 ano!r direction4 ,?is is %[n 9 ,diagram #d1 :]e ! holl[ ball ( cells :i* result$ f ! repeat$ division ( "o cell is repres5t$ 9 section4 ,"o side ( ! ball is pu%$ 91 & n[ ! bea/ consi/s ( two lay]s ( cells1 an out] protect+ & an inn] dige/+ 7,hydra & sea-anemone74 ,soon1 h[ev]1 x is f\nd m conv5i5t to h a tube = dige/+ food1 = !n diff]5t sub/ances c be dige/$ & absorb$ 9 diff]5t p>ts2 & ! refuse1 ( :i* ! animal c make no use1 ne$ n be br\ght back to ! m\? to be got rid (4 ,?is1 h[ev]1 requires a numb] ( o!r *anges 9 ! /ructure ( ! animal1 :i* are r\ghly %[n 9 ,diagrams #e & #f4 ,x is n to our purpose "h to discuss ! developm5t ( animals or an animal2 b ! figures are wor? glanc+ at1 z !y %[ n only h[ c]ta9 ( ! cells are set ap>t = dige/+ food1 b also t a l>ge body consi/s really only ( a mass ( protoplasm1 compos+ k9dr$ cells ( common orig94 ,illu/ration3 ,,diagram #f4--,,%[+ ,,developm5t ,,( ,,an ,,embryo4 ,n[1 = obvi\s reasons1 ! long]1 )9 c]ta9 limits1 ?is tube is ! bett]4 ,all sorts ( diff]5t food-/uffs h to be act$ ^u 9 x1 & "s (f] consid]able resi/ance to dige/ion2 & ! fur!r !y h to travel 9 ! tube1 ! m *ance !re is ( _! be+ successfully treat$4 ,besides1 diff]5t p>ts h diff]5t functions1 & ! long] ! tube--aga9 )9 necess>y limits--! great] scope is !re = division ( lab\r1 & consequ5t economy4 ,! comp>ative l5g? ( ! alim5t>y canal is n ! same 9 all animals by any means4 ,c>nivor\s animals1 l ! cat1 ^: food is s(t & easily dige/$1 h a fairly %ort "o4 ,h]bivora1 l ! %eep1 ^: food is difficult to dige/ & mix$ ) mu* husk1 :i* is :olly indige/ible1 h a comp>atively v long "o4 ,man1 :o is omnivor\s1 b eats less & m judici\sly *os5 food ?an ei!r ( ! above classes1 has "o ( m$ium l5g?4 ,b 9 all cases among ! high] animals !re is an attempt made to obviate ! necessity ( increas+ ! l5g? ( ! animal by coil+ ! tube )9 ! body4 ,! annex$ diagram 7#g7 illu/rates ?is pr9ciple4 ,x %[s a s*ematic animal ^: dige/ive canal is mu* long] ?an itself4 ,illu/ration3 ,,diagram #g4--,,%[+ ,,h[ ,,! ,,dige/ive ,,canal ,,is ,,l5g!n$4 ,illu/ration3 ,,diagram #h4--;,,cross-,,section ,,( ,,! ,,dige/ive ,,tube4 ,! dige/ive canal has1 h[ev]1 ano!r function4 ,! cells :i* compose x h n only to secrete juices1 to conv]t ! food into a usable =m2 !y h !n to absorb x4 ,! ne>] a p>ticle ( food is to ! wall ( cells1 ! soon] x is rea*$ by ^! juices1 & ! less *ance !re is ( useful mat]ial be+ swept away & lo/4 ,9 view ( ?is fact1 along c]ta9 tracts ! dige/ive canal is fold$ inw>ds1 & !re are projections1 :i* increase ! numb] ( cells to secrete & _! opportunities ( absorption4 7,see ,diagram #h47 ,illu/ration3 ,,diagram #i4--,,%[+ ,,h[ ,,gl&s ,,arise4 ,"h aga9 we h an illu/ration ( a con/antly recurr+ ne$1 ) a device = meet+ x--increase ( surface )\t increase ( bulk4 ,we met ) x be=e 9 ! cellul> sy/em2 we %all meet ) x aga9 9 gl&s1 lungs1 & bra91 at lea/4 ,! importance ( a device = ga9+ ?is end is app>5t :5 "o rememb]s :at ! comp>ative value ( surface & bulk is to an animal1 & t1 :ile surface increases by ! squ>e1 bulk increases by ! cube4 ,! pr9ciple is press$ to an extreme1 toge!r ) ! alli$ pr9ciple ( division ( lab\r1 9 gl&s4 ,! object ( ^! is to increase ! numb] ( secret+ cells1 &1 z !y are delicate1 to keep !m protect$ f contact ) co>se p>ticles ( food4 ,&1 9 ord] t no?+ may int]f]e ) _! effici5cy1 !y are absolv$ f ! duty ( absorb+4 ,h5ce tubes gr[ out f ! cavity ( ! alim5t>y canal l9$ ) ! same cells1 b1 z no food ev] ent]s1 ! cells :i* l9e !m devote !mselves entirely to p\r+ out dige/ive juices4 ,gl&s diff] consid]ably 9 /ructure & 9 ! liquids :i* !y secrete4 ,"s are v small2 "s1 l ! liv]1 v l>ge4 ,9 "s ! tube is v %ort1 9 "s long1 coil$ & bran*$1 & sometimes ! gl& is connect$ ) ! surface by m or less ( a duct4 ,"s gl&s only secrete "o enzyme1 "s sev]al4 ,9 ea*1 h[ev]1 ! pr9ciple is t %[n 9 ,diagram #i1 no matt] h[ its /ructure is mask$ by ! bloodvessels & support+ cells or connective tissue :i* envelop x4 ,aft] a meal1 or1 r1 :5 ! process ( dige/ion is ov] & ! animal is beg9n+ to ?9k ab\t its next1 ! gl& cells />t prep>+ _! enzyme4 ,!re is great activity 9 ! nucleus1 & granules /ream out f x t[>ds ! lum5 ( ! gl& 9 mu* ! same way1 to take a homely illu/ration1 z bubbles 9 "s eff]vesc+ dr9k =m at ! bottom ( ! tumbl] & rise till ! surface is cov]$ ) foam4 ,at ! "r mom5t ^! granules are dis*>g$1 j z ! bubbles on ! surface ( a liquid break at a slight jog4 ,!y are usually n ! f]m5t or enzyme1 b its precursor1 a sub/ance :i* only turns into ! f]m5t :5 x gets outside ! cells4 ,! f]m5ts1 :5 =m$1 are v peculi> sub/ances ab\t :i* we %\ld l ! *emi/ to tell u m1 ?\gh great advances h be5 made 9 our k ( !m lately4 ,among o!r peculi>ities1 "o may m5tion t1 ?\gh !y w keep indef9itely if bottl$1 !y are easily de/roy$ by too extreme a temp]ature or too acid or alkal9e surr\nd+s1 t _! composition is entirely unkn[n1 &1 /range/ ( all1 t !y d n become us$ up4 ,a giv5 am\nt ( r5net w clot any am\nt ( milk )9 reasonable limits1 & yet rema9 r5net4 ,! cl]gyman has be5 quot$ z an illu/ration ( ! action ( a f]m5t1 & he makes a good "o4 ,he c make any numb] ( suitable m5 & wom5 into m>ri$ c\ples1 & yet 8 own /ate is un*ang$4 ,,iii4 ,9 man1 ! dige/ive process may be divid$ into ?ree /ages4 ,!y are arrang$ progressively1 s t ea* cle>s ! way = ! next1 & take place 9 ! m\?1 ! /oma*1 & ! upp] "p ( ! small inte/9e1 ! re/ ( ! canal be+ ma9ly occupi$ 9 absorption4 ,illu/ration3 ,,diagram #aj4--;,,g5]al ,,s*eme ,,( ,,! ,,alim5t>y ,,canal1 ,,) ,,its ,,(f%oots--,,lungs ,,& ,,gl&s4 ,by f> ! l>ge/ proportion ( ! food is c>bohydrate1 9 "s =m1 s "o naturally expects ! fir/ /age ( dige/ion w deal ) ! con/itu5ts :i* repres5t ?is class4 ,?is is ! case4 ,! food is tak5 into ! m\? 9 small quantities & gr\nd up ) ! tee?1 dur+ :i* process x is subject$ to ! action ( ! saliva4 ,?is fluid1 :i* is ! secretion ( ?ree pairs ( gl&s1 conv]ts a l>ge proportion ( ! c>bohydrates1 />*1 cane-sug>1 etc41 into a v simple sug> :i* is absorb$ directly x rea*es ! /oma*4 ,"o ( ! mo/ s5sational discov]ies ( ! physiologi/ has be5 t ! saliva leav+ ! gl& does n conta9 ! f]m5t necess>y to effect ?is *ange until x has be5 subject$ to ! action ( putrefactive bact]ia4 ,^!1 =tunately = u1 x is pleasant to "k1 simply sw>m 9 ! m\?4 ,:5 ! food is swall[$1 x passes v rapidly d[n ! fir/ "p ( ! alim5t>y canal1 :i* is /raight1 & is !n kept = "s "t 9 ! /oma*4 ,! /oma* diff]s f ! re/ ( ! canal 9 sev]al p>ticul>s1 among !m ! foll[+3 x is a l>ge cavity1 & is clos$ at ea* end by a valve to keep ! food 9 until x has be5 ?or\ghly treat$1 & x deals ) ! :ole mass ( food tak5 at a meal at "o "t1 & yet has no contrivances = increas+ its surface4 ,"h ! food is subject$ to a mo/ important & se>*+ exam9ation4 ,enclos$ 9 ?is bag1 x is ?or\ghly mix$ ) weak hydro*loric acid1 secret$ by num]\s gl&s1 & kept *urn+ r\nd & r\nd by ! muscul> action ( its walls1 t ! cont5ts may be kept well mix$4 ,! acid is j /rong en\gh to kill protoplasm1 & h5ce ! putrefactive bact]ia :i* 7 necess>y 9 ! m\?1 b w\ld be a v d\btful bless+ 9 ! int]ior ( ! body1 are dispos$ (4 ,o!r ?+s are also kill$4 ,n only does ! /oma* execute intrud+ bact]ia1 b x also kills a good deal ( our food4 ,fruit & salad consi/ l>gely ( /ill liv+ cells1 & occasionally !re is bigg] game1 e4g41 oy/]s4 ,"o ?+1 h[ev]1 ! acid does n kill1 & t is ! cells l9+ ! /oma*1 & x may z well be said "h t ! p>ts ( ! body expos$ to f]m5ts h ! v necess>y p[] ( resi/+ !m1 s t a normal animal does n dige/ itself4 ,! /oma*1 h[ev]1 is a kit*5 z well z a slaught]-h\se4 ,! ga/ric juice1 or secretion ( all ! gl&s op5+ into x1 conta9s1 besides ! acid1 two important f]m5ts1 bo? ( :i* act on proteids4 ,c>bohydrates are absorb$1 b n dige/$1 9 ! /oma*1 z acid de/roys saliva4 ,"o ( ! f]m5ts is r5net1 an article famili> to ! cul9>y pr(ession1 :i* solidifies milk4 ,! o!r acts on proteids g5]ally1 conv]t+ !m ultimately into a v simple =m1 peptone1 :i* is absorb$ at once4 ,h[ mu* ( ! proteid 9 ! /oma* is conv]t$ into peptone is n kn[n1 = ! action ( acid alone is suffici5t to enable x to be absorb$4 ,a solution ( proteid1 e4g41 :ite ( egg1 is q alt]$ if made slightly acid2 x no long] coagulates :5 boil$1 b ! *ange ( ! mo/ practical int]e/ is t1 if inject$ into ! ve9s1 x seems to become "p ( ! blood1 :ile ord9>y proteids act z poisons4 ,! peptoniz+ f]m5t1 h[ev]1 has "o v important function3 x dige/s ! collag5 ( ! connective tissue1 ! sub/ance :i* becomes gelat9 :5 boil$4 ,! reason :y ?is is s important is n only t no?+ else 9 ! body affects x1 b t fat is enclos$ 9 x1 & if x 7 n ?us set free w\ld pass ?r\gh ! body unabsorb$4 ,! f9al /age is ! dige/ion by ! pancreatic juice4 ,aft] ! food has be5 expos$ = "s "t to ! ga/ric juice1 x is all[$ to escape a little at a "t f ! /oma*1 & cont9ues its way along ! alim5t>y tube4 ,be=e x has gone _m in*es x comes to ! op5+s ( two ducts1 ^? ( ! liv] & ! pancreas1 & imm$iately ! acid /imulates !m1 & ! gl&s p\r out _! secretion4 ,t ( ! liv] is l>gely excretion or refuse f ! blood )\t direct action on ! food1 b x enables ! pancreatic juice to d its "w by mak+ ! food aga9 alkal9e1 & /imulates ! muscul> coats ( ! inte/9e to =ce its cont5ts along4 ,t ( ! pancreas is ! mo/ important dige/ive fluid 9 ! body1 conta9+ _m f]m5ts2 x acts alike on proteids1 c>bohydrates1 & fats--9 fact1 dige/s ev]y?+--s t ! re/ ( ! long tube is fre$ f any m labori\s duty ?an absorb+ !m z !y pass4 ,,note4--,! dige/ive f]m5ts are n[ prep>$ = exam9ation by *opp+ up ! gl& & plac+ x 9 glyc]9e2 ?is extracts ! f]m5t & pres]ves x f ! action ( bact]ia4 ,! fir/ exp]im5ts on dige/ion1 h[ev]1 con/itute "o ( ! romances ( physiology4 ,a ,canadian nam$ ,/4 ,m>t9 got into tr\ble ) ,r$ ,indians :il/ 9 ! ,unit$ ,/ates1 ,am]ica1 & 0 %ot ?r\gh ! body4 ,! surgeon :o att5d$ him 0 unable to make ! w\nd close1 & :5 x heal$ !re rema9$ an op5+ 9 ! man's body communicat+ directly ) 8 /oma*4 ,! surgeon1 ,beaumont1 saw possibilities 9 ?is1 &1 obta9+ ga/ric juice f 8 pati5t1 made ^? classical exp]im5ts :i* entitl$ him to a place among ! fa!rs ( physiology4 ,am]icans d well to be pr\d ( ,beaumont1 = x co/ him _m sacrifices1 & 8 pati5ce & c\rage are above praise4 ,n only 0 he devoid ( all b ! crude/ appliances out 9 ! backwoods1 b 8 subject prov$ intractable & m]c5>y4 ,no soon] did he discov] 8 value ?an he cross$ ! bord]1 & refus$ to return except ^u exorbitant paym5t4 ,ev5 aft] ?is _h be5 arrang$1 he repeat$ ! p]=mance :5ev] he ?\ght fre% extortion possible4 ,9 spite ( ^! difficulties1 ! inve/igations prov$ wond]fully accurate & complete4 ,,iv4 ,( ! absorption ( ! mat]ials ?us prep>$ x is n necess>y to say mu* 9 a "w ( ?is compass1 b ! absorption ( oxyg5 is too important to be pass$ ov]4 ,oxyg5 is requir$ by ! body pure1 &1 z x is uncomb9$ ) any?+ 9 ! air1 x ne$s no dige/ion to free x4 ,a special organ1 h[ev]1 is necess>y to absorb x4 ,?is is ! lung4 ,! lungs orig9ate1 j l a gl&1 by a p\*+ ( ! alim5t>y canal ne> its orig91 b diff] f a gl& 9 _! cells be+ v mu* flatt5$1 to (f] a l>ge surface to ! air on "o side & to ! bloodvessels on ! o!r4 ,incessantly dur+ life air is be+ drawn into ! lungs2 t ! cells to :i* x is !re expos$ may transf] its oxyg5 to ! blood2 & !n1 aft] ! cells h also transf]r$ ! c>bonic acid gas f ! blood to ! air1 driv5 out aga9 to be replac$ by fre%4 7,! me*anical means by :i* ! lungs are fill$ & empti$ come "u ano!r head+47 ,v4 ,food hav+ be5 absorb$ by cells set ap>t = ! purpose1 ! next problem is1 ,h[ is x di/ribut$ to ^? specializ$ = o!r "w8 ,! m$ium = ?is di/ribution is a liquid call$ lymph4 ,all ! spaces 9 ! body are fill$ ) lymph1 all ! organs ba!d ) x1 e cell moi/5$ ) x2 yet x is comp>atively /agnant1 & ! food has to be convey$ f ! walls ( ! alim5t>y canal to ! lymph 9 ! neighb\rhood ( ! cell requir+ n\ri%m5t by a m exp$iti\s ag5t4 ,?is is done by ! blood4 ,illu/ration3 ,,diagram #aa4--,,pr9ciple ,,( ,,! ,,sy/em ,,( ,,bloodvessels4 ,illu/ration3 ,,diagram #ab4--,,pr9ciple ,,( ,,d\ble ,,circulatory ,,sy/em4 ,! blood is a fluid ak9 to ! lymph1 b conf9$ 9 a sy/em ( tubes4 ,?r\gh ^! tubes x is driv5 at a consid]able velocity1 & 9 ! c\rse x takes passes )9 a reasonable di/ance ( e cell 9 ! body4 ,z x passes ! cells ( ! alim5t>y canal1 !y dis*>ge ! nutrim5t !y h absorb$ into x2 z x passes ?r\gh ! o!r organs ( ! body1 x dis*>ges ! requisite mat]ials into ! lymph ba?+ ! actual cells3 ^! are !n able to help !mselves4 ,! lymphatic sy/em is v simple4 ,lymph is practically fluid :i* has exud$ ?r\gh ! walls ( ! bloodvessels1 & is l ! plasma ( ! blood1 a ?9 solution ( proteids 9 wat] conta9+ j en\gh salt to hold !m 9 solution4 ,f diff]5t p>ts ( ! body a s]ies ( tubes run t[>ds ! he>t1 go+ up ) increase 9 size & decrease 9 numb] z !y ne> x4 ,into ^! tubes ! lymph is =c$ ) e movem5t ( ! body4 ,at a sl[ rate1 b v>y+ ) ! activity ( ! animal1 x is =c$ to fl[ along ^! tubes1 regurgitation be+ prev5t$ by valves at int]vals1 until x rea*es ! place :]e ! lymphatic vessels jo9 a l>ge ve91 & x is p\r$ back into ! blood-/ream1 ?us complet+ its cycle4 ,! blood is entirely conf9$ 9 a clos$ sy/em ( tubes1 along :i* x moves always 9 ! same direction4 ,! ma9 pr9ciple ( ! sy/em is t ( a r+4 ,"o side ( ! r+ is split into a va/ numb] ( f9e tubes to give a l>ge surface = absorption & dis*>ge ( food among ! cells2 ! o!r side is a s+le tube1 ) an enl>gem5t 9 :i* ! blood f diff]5t p>ts is mix$ 7see ,diagram #aa74 ,?is enl>gem5t1 :i* is contractile & fitt$ ) valves1 rhy?mically draws ! blood 9 f "o direction & pumps x out 9 ano!r4 7,! me*anics ( ! process we %all /udy lat]47 ,z a matt] ( fact1 ?is sy/em is tw(old1 z 9 ,diagram #ab4 ,9 pass+ ?r\gh "o-half ( its c\rse ! blood absorbs oxyg5 9 ! lungs2 9 ! o!r x yields oxyg5 to ! tissues1 & absorbs1 :il/ pass+ ov] ! alim5t>y canal1 proteid1 c>bohydrate1 wat]1 & salts1 :i* are duly di/ribut$ to ! o!r organs4 ,fat is absorb$ by ! lymph direct1 b p\r$ into ! blood = di/ribution4 ,! blood :i* passes ov] ! alim5t>y canal on its way back to ! he>t goes ?r\gh ! liv]4 ,9 ?is gl& x leaves ! c>bohydrate :i* x has tak5 up1 & a l>ge /ore is laid d[n !re aft] a meal1 to be dol$ out z x is want$4 ,blood also passes ?r\gh ! liv] f ! sple51 :]e x has be51 s to speak1 ov]haul$ = repairs4 ,illu/ration3 ,,diagram #ac4--,,s*eme ,,( ,,! ,,circulatory ,,sy/em4 ,blood sy/em on ! "r1 lymph sy/em on ! left4 ,z ! m$ium = *emical communication ?r\gh\t ! community ( cells1 ! blood has ano!r all-important & obvi\s function1 viz41 t ( cle>+ away ! wa/e products ( life4 ,( ^! !re is1 ( c\rse1 ! same quantity z ( new mat]ial introduc$4 ,c>bonic acid gas is dis*>g$ into ! lungs1 b all ! nitrog5 & mo/ ( ! o!r elem5ts 9 ! new comb9ations :i* protoplasm has made !m assume leave by ! kidneys1 plus a little wat] by ! sk9 z sweat & a few items dis*>g$ into ! la/ "p ( ! alim5t>y canal among/ ! unabsorb$ portions ( ! food4 ,9 _! con/itu5ts1 blood & lymph resemble "o ano!r1 be+ bo? weak solutions ( salts & proteid mat]ial2 b ! blood is di/+ui%$ f ! lymph by ! pres5ce ( innum]able extremely m9ute bodies1 :i* give x its r$ col\r4 ,^! corpuscles1 to give !m _! prop] "n1 are ! vehicle by :i* oxyg5 is transport$ f ! lungs to ! tissues4 ,!y consi/ ( an envelope ( protoplasm fill$ ) a r$ fluid 7hmoglob971 :i* comb9es loosely & easily ) oxyg54 ,9 %ape !y are discoid1 ) a ?ick5$ rim & biconcave sides1 ano!r device = increas+ surface & r$uc+ bulk4 7,see ,diagram #ad47 ,illu/ration3 ,,diagram #ad4--;,a ,,r$ ,,blood ,,corpuscle4 ,) "o m fact we may n[ conclude ! *emical survey ( ! body4 ,! blood has to pass ?r\gh c]ta9 gl&s1 or x becomes poison$1 & ?is q ap>t f :e!r ! gl& secretes heal?ily or n4 ,disease ( ! ?yroid 7a ductless gl& 9 ! ,adam's apple7 causes goitre2 ( ! supr>5al1 ,addison's disease2 ( ! pancreas1 diabetes4 ,:e!r ^! organs secrete "s sub/ance into ! blood :i* c\nt]acts poisons =m$ 9 x1 or :e!r !y remove injuri\s elem5ts f x1 is n c]ta91 b !y are necess>y to keep ! great means ( *emical communication 9 ord]4 ,,note4--,! ?yroid gl& no long] secretes any?+ into ! alim5t>y canal1 & its duct disappe>s at an e>ly age4 ,if1 h[ev]1 x become diseas$ or is surgically remov$1 ! di/ress+ symptoms ( goitre sup]v5e4 ,su* a pati5t may be completely cur$ by graft+ a ?yroid1 excis$ f ano!r animal1 any:]e 9 8 body4 ,doctors usually1 h[ev]1 give ! pati5t extract ( %eep's ?yroid ei!r 9 pills or injections4 ,,essay ,,iii4 ,,! ,,me*anics ,,& ,,physics ,,( ,,! ,,body4 ,i4 ,9 ! prec$+ essay we reg>d$ protoplasm z a *emical factor 9 ! univ]se4 ,we h se5 h[ x is always *ang+1 always tak+ 9 food1 always giv+ (f wa/e mat]ials4 ,we h se51 too1 t x gr[s & t x does "w1 & t 9 a l>ge mass ! cells :i* compose x %>e ! lab\r in/ead ( ea* compon5t cell p]=m+ all ! vital functions4 ,we h n[ to consid] ! "w :i* protoplasm does--9 a ^w1 ! me*anical effect ( ! *emical actions j describ$4 ,! simple/ movem5t ( protoplasm is to be se5 by ! aid ( ! microscope 9 c]ta9 vegetable cells1 :]e granules seem always /ream+ ab\t 9 diff]5t directions4 ,a /ep high]1 & we f9d ?is /ream+ movem5t conv]t$ into movem5ts ( ! :ole cell4 ,9 ! simple/ unicellul> animals ! fluid protoplasm is conta9$ 9 a membrane1 or d5s] b\nd+ lay]1 to :i* are atta*$ f9e filam5ts spr++ f a m9ute body kn[n z ! c5trosome4 ,^! c5trosomes--= !re are sometimes sev]al 9 a cell--seem to control ! me*anical dep>tm5t1 j z ! nucleus does ! *emical4 ,along ! fibrils at int]vals are m9ute globules1 & by wat*+ ! di/ance betwe5 !m x is se5 t ! fibrils und]go *anges 9 l5g?1 pull+ 9 ! membrane :5 !y %ort51 & lett+ ! cell fl[ out 9 any direction :5 !y relax4 ,by adju/+ ^! two movem5ts to balance "o ano!r1 ! cell c move 9 any direction1 surr\nd & engulf p>ticles ( food1 & assume a /range v>iety ( %apes4 7,see ,diagram #a47 ,illu/ration3 ,,diagram #ae4--;,,cell ,,division4 ,9 "s cells1 probably 9 all1 ! c5trosome presides ov] division4 ,cells1 h[ev]1 d n always divide 9 ! same way4 ,"s simply l5g!n1 ! nucleus also l5g!n+ inside1 become con/rict$ 9 ! middle l a dumb-bell1 & sep>ate4 7,see ,diagram #ae47 ,illu/ration3 ,,diagram #af4--;,,cell ,,division4 ,o!rs manage diff]5tly4 ,9 !m ! nucleus simply bur/s1 & turns its ess5tial elem5ts1 a numb]--always a con/ant numb]--( co>se ?reads1 adrift4 ,mean:ile1 two c5trosomes h mov$ to opposite ends ( ! cell1 & !re an*or$ !mselves by fibrils2 o!r fibrils spr++ f !m become atta*$ to ! nucle> ?reads1 & :5 all is ready pull !m ap>t1 equally divid$1 to _! respective ends1 :]e !y re-=m into two fre% nuclei4 7,see ,diagram #af47 ,unicellul> animals1 :i* are con/ant 9 %ape & swim in/ead ( fl[+ :5 !y want to get any:]e1 h at fir/ sight no?+ 9 common ) ^? :i* d ! latt]4 ,f _! surfaces spr+ fr+es ( free protoplasmic ?reads1 call$ cilia1 f _! fanci$ resemblance to eyela%es1 :i* s]ve z motor organs1 & beat ! wat] l o>s4 7,see ,diagram #b47 ,waves ( movem5t1 z !y la% "o aft] ano!r1 all 9 ! same direction1 seem to pass ov] ! cell1 & x is propell$ ?r\gh ! wat]2 :ile o!rs1 :i* are situat$ 9 ! neighb\rhood ( ! cell's m\?1 /ir ! wat] into eddies1 & drive food p>ticles into x4 ,illu/ration3 ,,diagram #ag4--;,,cilia ,,( ,,an ,,epi!lial ,,cell4 ,^! cilia are important1 z !y are adapt$ = _m purposes 9 l>ge animals4 ,! cells :i* l9e ! cavity at ! back ( ! nose1 ! tubes ( ! lungs1 & o!r p>ts ( ! body1 h a few cilia on _! free surface1 & x is 9 !m t ! /ructure ( ^! organs c be/ be made out4 ,at ! foot ( ea* cilium is a m9ute globule1 f :i* a f9e fibril passes into ! cell1 & ! fibrils1 collectively =m+ a lea%1 are atta*$ to its opposite end4 7,see ,diagram #ag47 ,x seems highly probable t ! globule is a c5trosome giv+ rise to two fibrils1 "o atta*$ z describ$1 ! o!r pass+ up "o side ( ! cilium1 & fa/ to its apex4 ,! result ( ?is arrangem5t is t :5 ! fibrils contract ! cilium is b5t ov] ) a j]k to ! side up :i* ! fibril runs1 & :5 !y relax x sl[ly /raight5s itself4 ,!re is1 !re=e1 no fundam5tal diff]5ce betwe5 ?is & ! o!r mode ( progression2 bo? are dep5d5t ^u ! c5trosome4 ,f9ally we h muscle cells4 ,^! are only f\nd 9 a fairly complicat$ animal1 s9ce !y are a product ( ! division ( lab\r pr9ciple1 & _! sole bus9ess is movem5t4 ,!re are two v>ieties ( muscle1 b ! pr9ciple is ! same 9 bo?--a long ?9 cell1 ) fibrils trav]s+ its l5g? ^: contraction causes ! cell to %ort5 & ?ick51 ?us r$uc+ ! di/ance betwe5 its two ends4 ,at pres5t ! developm5t ( muscle & ! way 9 :i* x #8contracts1' to use ! ^w accept$ 9 ?is case = describ+ a r$i/ribution ( bulk1 are little und]/ood1 & !re are accord+ly _m op9ions2 b ,i ?9k c>eful /udy w ev5tually %[ t "s modification ( ! c5trosome1 ) its contractile fibrils1 is responsible = ! movem5t4 ,illu/ration3 ,,diagram #ah4--,,muscle4 ,! two v>ieties are3 ! smoo?1 or involunt>y1 & ! /rip$1 or volunt>y1 muscle4 ,smoo? muscle consi/s ( sp9dle-%ap$ cells ) "o elongat$ nucleus4 7,see ,diagram #ah1 ,fig4 #a47 ,x only contracts v sl[ly1 & is n "u control ( ! w2 b x is v abundant 9 ! body1 s9ce x effects practically all ! movem5ts ( ! alim5t>y canal & bloodvessels4 ,volunt>y or /rip$ muscle1 s call$ f its appe>ance "u ! l[ p[] ( a microscope1 consi/s ( long fibres1 ea* conta9+ _m nuclei4 7,see ,diagram #ah1 ,fig4 #b47 ,its protoplasm is ri* 9 hmoglob91 & 9 x1 "u p[]ful microscopes1 c be made out two k9ds ( fibrils3 ,ru!r=d's fibrils1 ! complicat$ /ructure ( :i* gives muscle its /rip$ appe>ance2 & ,m>%all's fibrils1 :i* are mu* f9] & m difficult to see4 ,! muscle ( ! he>t1 ?\gh n "u control ( ! w1 is /rip$2 b x diff]s f ord9>y /rip$ muscle 9 be+ made up ( small bran*$ cells ) only "o nucleus4 ,! way 9 :i* ! ?ree elem5ts ( /rip$ muscle contribute to a contraction is practically unkn[n1 & ! subject ( mu* dispute4 ,9 fact1 "o c\ld h>dly wi% = a bett] soil = !ories1 & "s :i* gr[ 9 x are v wond]ful inde$4 ,we h reason = suppos+ t !re are two contractile sub/ances--"o :i* gives a %>p twit*1 ! o!r a sl[1 h>d pull2 & on ! :ole !re seems good reason to believe t ,ru!r=d's fibrils give ! sudd5 movem5ts1 :ile ,m>%all's give ! m =cible ones2 & t ! ord9>y protoplasm ( ! cell is re/rict$ to ! duty ( n\ri%+ ! fibrils4 ,illu/ration3 ,,diagram #ai4--,,/rip$ ,,muscle ,,fibre1 ,,m ,,highly ,,magnifi$ ,,?an ,,9 ,,diagram #ah4 ,! muscle cells are modifi$ f among ^? ( ! bud =m+ ! middle lay]s ( ! embryo4 7,see ,diagram #e47 ,o!r cells ( ?is bud =m connective tissue1 by1 s to speak1 sp9n+ long fibres ( ! sub/ance call$ collag51 :i* turns to gelat9 :5 boil$4 7,see ,diagram #bj47 ,?is connective tissue p]meates ! :ole body1 af=d+ a firm f\ndation = ! _m lay]s ( cells :i* =m ! sk9 & ! s+le lay] ( dige/ive cells2 support+ ! o!r organs ?r\gh\t1 & keep+ ! diff]5t p>ts ( ! body 9 _! places1 9 do+ :i*1 h[ev]1 x is assi/$ by o!r fibres :i* are n collag5\s1 b ela/ic4 ,x also =ms tracts :i* become lymph & blood vessels4 ,9 p>ts ( ! animal :i* require special support x =ms solid rods1 ! collag5 comb9+ ) calcium salts to =m a cle>1 h>d sub/ance--c>tilage4 ,at "o p]iod 9 ! developm5t ( an animal or animals we f9d ! only solid support is c>tilage1 b c>tilage is n suffici5tly rigid = a v l>ge bea/1 especially on l&1 s is only us$ = outly+ p>ts1 ! ma9 framework be+ bone4 ,illu/ration3 ,,diagram #bj4--;,a ,,connective-,,tissue ,,cell ,,giv+ ,,rise ,,to ,,long ,,collag5\s ,,fibres4 ,bone is =m$ v mu* z if ,nature 7 rectify+ a mi/ake4 ,:5 a rod ( c>tilage is unequal to its "w x is eat5 holl[1 & fre% connective-tissue cells immigrate & fill up ! cavity1 ev5tually lay+ d[n a f9e network ( cells 9 its place1 ! me%es ( :i* are fill$ ) inorganic calcium salts1 *iefly phosphate ( lime4 ,nature !n b5efits by exp]i5ce1 & ! la/ bones to be =m$ are n prec$$ by any make%ift c>tilage1 b built up /raight away 9 ord9>y connective tissue4 ,?is br+s u back aga9 to muscle1 = ! object ( ne>ly all ! volunt>y muscle is to cause movem5t among ! bones4 ,= ?is purpose ! muscle cells or fibres are arrang$ p>allel to "o ano!r1 & b\nd up toge!r by connective tissue1 ! :ole bundle be+ kn[n z #8a muscle4' ,! two ends ( a muscle are atta*$ to two bones by connective tissue1 :i* sometimes =ms a %ort cord1 or t5don4 ,!n1 :5 ! muscle contracts1 ! two places ( its atta*m5t are pull$ t[>ds "o ano!r1 & some?+ has to move4 ,b be=e say+ m ab\t ! way 9 :i* ! bones are jo9t$ & muscles atta*$--9 fact1 :at movem5ts are possible 9 ! human body--x w\ld be z well "h to describe ! *ief prop]ties ( muscle & ! way 9 :i* !y are /udi$4 ,,ii4 ,illu/ration3 ,,diagram #ba4--;,,app>atus ,,= ,,record+ ,a ,,muscul> ,,contraction4 ,! way 9 :i* volunt>y muscle is /udi$ is v simple4 ,a frog is kill$ by ?ru/+ a probe into ! bra9 & d[n ! sp9al cord1 & a muscle is !n dissect$ out & atta*$ to a piece ( app>atus 7see ,diagram #ba7 9 su* a way t on its contract+ x raises a lev]1 & draws a l9e on a mov+ surface4 ,! rate at :i* ! surface is mov+ is asc]ta9$1 s t ! nature ( ! curve1 :i* is a graphic record ( ! contraction1 c be analyz$4 7,see ,diagram #bb47 ,= in/ance1 :5 an electric %ock is us$ to make ! muscle contract1 we f9d t a slight %ock causes a small contraction1 z %[n by a l[ curve1 :ile a /rong] "o1 up to a c]ta9 po9t1 causes an increase4 ,illu/ration3 ,,diagram #bb4--;,,graphic ,,record ,,( ,a ,,response ,,to ,a ,,s+le ,,/imulus ,,appli$ ,,at ,a4 ,l[] l9e tun+-=k records ( 4 ,b hav+ describ$ h[ muscle is /udi$1 x is only necess>y to /ate a few facts conc]n+ x2 to discuss muscle1 fully describ+ ! exp]im5ts by :i* its m obscure prop]ties h be5 elucidat$1 & ! devices by :i* causes ( error h be5 elim9at$1 w\ld fill volumes4 ,illu/ration3 ,,diagram #bc4--;,,contractions ,,) ,,two ,,/imuli ,,at ,,diff]5t ,,int]vals ,,( ,,"t4 ,muscle is ?r[n into a /ate ( contraction by an impulse rea*+ x f a n]ve1 b x contracts q z readily if excit$ directly by a me*anical or electrical %ock4 ,a second %ock causes a second contraction1 or1 if ! muscle is /ill 9 a /ate ( contraction ow+ to ! fir/1 causes x to contract /ill m4 7,see ,diagram #bc47 ,if a numb] ( /imuli are appli$ to a muscle 9 su* rapid succession t ! effect ( ! prec$+ "o has n pass$ (f by ! "t ! next arrives1 x w contract z f> z possible1 & rema9 contract$--a /ate kn[n z tetanus4 7,see ,diagram #bd47 ,a muscle is !re=e kept 9 a /ate ( contraction by a cont9u\s n]v\s ef=t1 n arrang$ & !n left contract$4 ,illu/ration3 ,,diagram #bd4--,,tetanus4 ,illu/ration3 ,,diagram #be4--;,,fatigue ,,curves4 ,fa/ drum3 a1 po9t ( /imulation4 ,e t5? contraction record$4 ,illu/ration3 ,,diagram #bf4--;,,effect ,,( ,,fatigue ,,on ,,muscul> ,,contraction4 ,sl[ drum4 ,e contraction record$4 ,v>i\s conditions alt] ! "* ( a muscul> response4 ,) repeat$ /imuli at %ort int]vals a muscle fatigues1 & ea* contraction becomes small] 9 ext5t & long] 9 duration4 7,see ,diagrams #be & #bf47 ,if ! muscle has to lift a load x has a c]ta9 *eck on its contraction1 & its relaxation "t is %ort5$4 ,temp]ature also affects muscul> contraction1 mod]ate increase caus+ a %>p]1 & mod]ate cool+ a sl[]1 rise & fall ( ! lev] on /imulation4 7,see ,diagram #bg47 ,la/ly1 we h drugs :i* ex]t an influ5ce1 b ! only "o ( ^! :i* x is necess>y to m5tion "h is v]atria1 :i* makes ! sl[ly contract+ fibrils cont9ue _! activity aft] ! quick ones h subsid$4 7,see ,diagram #bh47 ,illu/ration3 ,,diagram #bg4--;,,effect ,,( ,,temp]ature4 ,illu/ration3 ,,diagram #bh4--,,v]atria ,,curve4 ,f9ally1 !re are ! electrical *anges 9 muscle4 ,^!1 aga91 may be pass$ ov] briefly1 s9ce !y are n easily und]/ood or describ$4 ,to put ! facts 9 a nut%ell1 ! "p ( a muscle :i* is 9 activity is negative to all o!r p>ts4 ,?us1 if a muscle be dissect$ out & cut across1 ! activity at ! seat ( ! injury1 :ile x la/s1 causes a curr5t to pass ?r\gh a galvanomet] f un9jur$ p>ts to ! w\nd$4 7,see ,diagram #bi47 ,aga91 if a muscle be dissect$ out )\t injury1 connect$ at two po9ts ) a galvanomet]1 & !n /imulat$ at "o end1 z ! wave ( contraction passes along x1 fir/ "o1 !n ! o!r1 contact becomes negative4 7,see ,diagram #cj47 ,s1 ,/imulat+ electrodes2 ,n1 contraction :i* m>ks ! wave ( excitation pass+ along ! muscle2 ,g1 galvanomet] :i* %[s t ! seat ( activity 7,n7 is negative to ! re/ ( ! muscle4 ,illu/ration3 ,,diagram #bi4--;,,injury ,,curr5t3 ,,cross-,,section ,,( ,,muscle ,,negative ,,to ,,re/4 ,illu/ration3 ,,diagram #cj4--;,,action ,,curr5t4 ,9 pass+1 x may be m5tion$ t1 z ! he>t is a muscle slung obliquely across ! body1 & waves ( contraction are cont9ually pass+ d[n its long axis1 ! :ole body is affect$ by cont9ual electrical *anges4 ,by v delicate in/rum5ts x c be demon/rat$ t ) ea* beat ! two h&s alt]nately become electrically positive & negative to ea* o!r4 ,:il/ deal+ ) ! electrical ph5om5a ( muscle1 x may be z well to /ate t n]ve fibres1 :i* are /udi$ ) v mu* ! same app>atus1 %[ ! same electrical *anges1 ! po9t ( injury or ( ! greate/ activity be+ negative to all ! re/4 ,s+le cells are less easily inve/igat$1 b 9 gl&s x is possible to %[ t ! same rule holds4 ,und\bt$ly ! mo/ curi\s fact ab\t ! g5]ation ( electricity by protoplasm is t1 by a modification ( muscle & n]ve1 :i* causes !m to lose _! ord9>y prop]ties1 !y are conv]t$ into a special organ = giv+ electric %ocks4 ,arm$ ) p[]ful batt]ies ( ?is description1 an o!rwise r helpless class ( fi% are enabl$ to def5d !mselves f _! enemies1 & deal unexpect$ dea? to _! m agile prey4 99 99 99 99 99 ,hav+ n[ run ov] a few ( ! physical prop]ties ( protoplasm1 we may pass on to a brief inve/igation ( ! movem5ts we f9d 9 ! body ( man4 ,,iii4 ,9 describ+ ! movem5ts ( ! body1 we %all h to treat !m z sev]al & di/9ct1 z inde$ !y are2 b ! fact %\ld n be lo/ sight ( t !y _c really be isolat$3 "o idea embraces ! :ole4 ,two k9ds ( movem5t may1 h[ev]1 be di/+ui%$ 9 ! vital functions3 movem5t ( ! actual cells1 su* z muscles2 & movem5t ( non-protoplasmic elem5ts act$ ^u by ! cells--e4g41 lymph4 ,!re is a p>allel to ?is 9 ! *emical side ( life1 :]e we f9d "s ph5om5a peculi> to ! liv+ elem5ts1 & o!rs1 l dige/ion1 go+ on 9 ! liv+ body1 b outside ! cells4 ,tak+ ! movem5ts 9 ! natural ord]--t is1 proce$+ f ! simpl] to ! m complex--! fir/ to be consid]$ is und\bt$ly t ( ! leucocytes1 or g5]al scav5g]s ( ! tissues4 ,! body consi/s1 s f> z we h def9$ its anatomy1 ( ?ree lay]s ( cells1 & its %ape is t ( a tube ) holl[ walls4 7,see ,diagram #f47 ,)9 ! cavity ( ! body are v>i\s organs1 su* z ! muscles1 :i* are =m$ f ! middle lay]2 & its space is l>gely r$uc$ by gl&s1 lungs1 & o!r ramifications ( ! inn] lay] :i* =ms ! alim5t>y canal4 ,^! organs hang m or less freely 9 ! body cavity1 slung to its walls by envelop+ %eets ( connective tissue1 ! :ole be+ ba!d 9 lymph4 ,n[1 9 su* an arrangem5t ! products ( we> & te> mu/ accumulate4 ,cells "h & !re die = v>i\s reasons1 & pieces ( cells become deta*$ ev5 9 adult animals4 ,! int]ior ( a bone is always be+ eat5 away to decrease its weight1 or 9 ord] t x may be replac$ by fre% bone ( a clos] texture1 & 9 "y animals & embryos !re are _m /ructures :i*1 useful = a "t1 h ev5tually to be remov$2 z an in/ance1 we may quote ! tadpole's tail4 ,9 fact1 if ! tissues 7 left to !mselves1 ! body w\ld soon be *ok$ ) dbris1 & to avoid ?is x is suppli$ ) an army ( scav5g]s1 ! leucocytes4 ,! leucocytes are deta*$ cells :i* owe _! orig9 to ! middle lay]4 ,9 size !y are1 ( c\rse1 v small1 q invisible to ! nak$ eye4 ,9 appe>ance !y resemble unicellul> organisms ( ! amba type1 :i* we h _h occasion to m5tion sev]al times already 7,essay ,,ii41 ,section ,,ii42 ,essay ,,iii41 ,section ,i41 ,diagram #a74 ,!y are ( sev]al diff]5t v>ieties1 "s be+ l>g] & m active ?an o!rs2 b !y all w&] ab\t 9 ! lymph & blood l indep5d5t animals1 creep+ 9 & out betwe5 ! cells ( ! organs1 & dev\r+ any =eign matt] !y come across4 ,!y sometimes multiply1 l indep5d5t animals1 by division1 especially 9 ! pres5ce ( inflammation1 or :5 !y h mu* "w to d1 & a rapid increase 9 _! numb]s is ne$$2 & !y h be5 induc$ to live1 & fe$1 & multiply1 outside ! body 79 :i* case !y mu/ be consid]$ to h become indep5d5t organisms71 ?anks to ! c>eful att5tions ( ! exp]im5t]4 ,ap>t f _! duties ( dev\r+ ! inside lay]s ( bones & cle>+ away dead tissue1 !y are suppos$ by "s to assi/ 9 ! absorption ( food by creep+ betwe5 ! cells l9+ ! alim5t>y canal1 &1 aft] ?r[+ out arms to engulf p>ticles ( food1 return+ ) _! spoils into ! body4 ,p]haps1 h[ev]1 ! mo/ int]e/+1 or at any rate mo/ romantic1 ( _! _m & important functions are :at may be call$ _! em]g5cy duties4 ,frequ5tly p1 especially ^? :o live 9 smoky t[ns1 draw into _! lungs p>ticles ( du/ & soot1 :i* if left adh]+ to ! walls ( ! air cavities w\ld cause dang]\s irritation4 ,z if by magic a leucocyte w discov] ! pres5ce ( su* a nuisance1 &1 crawl+ betwe5 ! cells =m+ ! wall ( ! lung1 9 :i*1 by ! way1 x is outside ! body prop]1 w engulf x & c>ry x away ) him4 ,?is exploit1 h[ev]1 pales beside ! w>f>e :i* goes on 9 ! body betwe5 leucocytes & invad+ bact]ia4 ,a bact]ium ?rives 9 ! blood or lymph1 s9ce x f9ds itself 9 a w>m alkal9e fluid conta9+ complex organic sub/ances1 by break+ d[n :i* x c easily obta9 en]gy4 ,un=tunately1 ! products ( su* a process are frequ5tly virul5t poisons1 ! effect ( :i* ^u neighb\r+ cells produces ! di/ress+ symptoms :i* we associate ) disease4 ,no soon]1 h[ev]1 has ! bact]ium begun to g5]ate poisons1 ?an leucocytes1 influ5c$ by *emical attraction 7,essay ,i471 sw>m ^u x4 ,fir/ come leucocytes ( a small k9d1 full ( zymog5 granules1 :i* cr[d r\nd ! bact]ium till !y h cov]$ x4 ,aft] a "t !y creep away1 leav+ x dead4 ,!y are n[ 9 an exhau/$ condition1 & no long] conta9 granules1 hav+ d\btless dis*>g$ !m z a de/ructive f]m5t ^u _! enemy4 ,!n a leucocyte ( ano!r k9d moves to ! attack1 or1 r1 to cle> up ! rema9s1 = he is a l>ge1 non-granul>1 active fell[1 & eats up ! dead bact]ium by ! simple process ( engulf+ him :ole4 7,see ,diagram #ca47 ,a natural "q aris+ out ( ! /udy ( leucocytes is1 ,:at becomes ( !m8 ,p>ticles ( soot & simil> refuse c h>dly be consid]$ nutriti\s1 or ev5 dige/ible1 food1 & "o is r drawn to ! conclusion t ! leucocyte p]=ms its functions = ! good ( ! body at l>ge1 n ( itself1 & t :5 its "w is done x mu/ die4 ,_m leucocytes1 probably1 load$ ) unconsid]$ & undesirable trifles1 ca/ !mselves into ! alim5t>y canal1 & are got rid ( ) ! useless portions ( ! food2 b !y d n always h ! luck or en]gy to get to a natural outlet4 ,an unpleasantly famili> ph5om5on is ! boil4 ,"h we h "s irritat+ sub/ance "u ! sk9 sett+ up inflammation1 & leucocytes sw>m up to remove ! cause ( ! tr\ble4 ,be=e1 h[ev]1 ?is is done1 _m h p]i%$ 9 ! fray1 & !y h collect$ 9 numb]s to ! =mation ( :at is commonly kn[n z pus1 or matt]4 ,_! disp]sal into ! body is n[ nei!r easy nor desirable1 & ! surgeon usually lets !m escape f ! surface by a t\* ( ! lancet4 ,illu/ration3 ,,diagram #ca4 ,a1 ,eos9ophile leucocyte2 ,b1 bact]ium2 ,c1 leucocytes kill+ bact]ium ) _! enzyme2 ,d1 leucocytes leav+ bact]ium dead2 ,e1 hyal9e leucocyte dev\r+ dead bact]ium4 ,su*1 !n1 is v briefly ! /ory ( ! leucocyte1 neglect+ su* problems z ! diff]5ces betwe5 ^? f\nd 9 ! blood1 call$ :ite corpuscles to di/+ui% !m f ! r$ corpuscles1 ) :i* !y h no sort ( connection2 ^? f\nd 9 ! lymph1 call$ lymphocytes to di/+ui% !m f ^? f\nd 9 ! blood2 ^? caught 9 ! act ( dev\r+ bone1 call$ o/eocla/s2 & ^? f\nd ) bact]ia inside !m1 !re=e kn[n z phagocytes2 & )\t speculat+ on h[ long an individual lives1 & :e!r ! diff]5t v>ieties diff] 9 orig9 or are m]ely at progressive /ages ( developm5t4 ,! /udy ( leucocytes is "o ( ! mo/ fasc9at+ 9 physiology1 b we h _m o!r ?+s call+ = our att5tion1 & we h said en\gh ab\t ! "p !y play 9 ! life ( ! body to ju/ify our pass+ on to consid] ano!r ess5tial movem5t4 ,,iv4 ,next 9 natural ord] = consid]ation come ! movem5ts ( ! alim5t>y canal4 ,s f> we h consid]$ ?is /ructure z a *emical laboratory1 a tube consi/+ ( a s+le lay] ( cells :i* secrete f]m5ts into ! lum51 :]e dige/ion takes place1 & !n absorb ! products1 & we h n yet acc\nt$ = ! food travell+ along ! tube1 )\t :i* its functions1 z describ$ 9 ! e>li] "p ( ! book1 c\ld n be p]=m$4 ,t ! passage ( ! food is n due to gravitation is obvi\s f ! _m directions ( ! tube's coils--n to quote ! old in/ance ( a horse dr9k+1 9 :i* case ! liquid fir/ travels upw>ds4 ,"o mu/ !re=e conclude 9 fav\r ( "s muscul> me?od ( propulsion4 ,we h s f> describ$ ! alim5t>y canal z a s+le lay] ( cells1 b x mu/ be obvi\s t ^! s(t secret+ portions ( ! tube are n capable ( vigor\s movem5t4 ,! canal prop] is surr\nd$ by a t\gh %ea? ( connective tissue :i* prev5ts its be+ ov]di/5d$ or ruptur$1 &1 by means ( a lay]--or1 r1 two lay]s--( non-/rip$ muscle :i* x conta9s1 produces ! movem5ts :i* result 9 ! passage ( its cont5ts along ! tube4 ,^! two lay]s lie well to ! outside ( ! connective-tissue %ea?4 ,! fibres ( ! inn] lay] are arrang$ circul>ly1 s z to =m r+s r\nd ! tube2 ^? ( ! out] h a longitud9al direction1 runn+1 !re=e1 p>allel ) its long axis4 ,:5 ! =m] contract1 ! diamet] ( ! tube is r$uc$1 :ile contraction ( ! latt] has ! effect ( enl>g+ x4 7,see ,diagram #cb47 ,! movem5ts ( ! inte/9e are :at is kn[n z p]i/altic4 ,contraction ( ! muscle fibres is n simultane\s 9 all p>ts1 b passes 9 waves along x4 ,j 9 front ( ! food ! longitud9al fibres contract1 & ?us (f] less resi/ance1 :ile j beh9d ! circul> fibres r$uce ! size ( ! tube1 & s get up a pressure4 ,! result ( a numb] ( successive waves ( contraction pass+ d[n ! alim5t>y canal is t ! food is propell$ along x4 ,illu/ration3 ,,diagram #cb4--,,to ,,illu/rate ,,! ,,passage ,,( ,,food ,,along ,,! ,,inte/9e4 ,! arrangem5t ( ! muscle v>ies 9 places to suit special ne$s4 ,:]e ! tube sudd5ly enl>ges to =m ! /oma*1 & :]e ! /oma* sudd5ly n>r[s to ! inte/9e1 !re are two /rong r+s ( muscle1 ^: con/rict+ influ5ce conv]ts ! enl>gem5t into a clos$ *amb] dur+ ga/ric dige/ion2 :ile ! coats :i* actually clo! x "h run obliquely1 & _! activity causes ! cont5ts to be sl[ly *urn$ ab\t inside4 ,?us x w be se5 t x is n only ! volunt>y muscles :i* give ! alim5t>y sy/em its opportunities2 )\t ^! unobtrusive non-/rip$ cells we %\ld toil = our bread & swall[ x 9 va94 ,v4 ,our next /ep1 aft] hav+ survey$ ! pr9ciple ( movem5t by :i* ! *emical necessities ( ! body are expos$ to its absorb+ surface1 mu/ be to see h[ ! fluid :i* transports !m is made to pass along ! tubes conta9+ x4 ,we h already _h occasion to describe h[ ^! blood & lymph vessels ramify ?r\gh all ! organs1 :5 we 7 deal+ ) ! *emical influ5ce ( ! blood & lymph4 ,! tubes ?r\gh :i* ! lymph is br\ght back to ! blood-/ream h ?9 walls1 & no muscle ( _! own4 ,!y are subject$1 h[ev]1 to a con/antly v>y+ pressure by ! movem5ts ( ! limbs & trunk1 & z1 ow+ to valves inside !m1 ! lymph c only escape 9 "o direction1 !re is a con/ant fl[ t[>ds ! junction ) ! bloodvessels4 ,! bloodvessels are q diff]5t4 ,a f> m c]ta9 & exp$iti\s curr5t is necess>y--h5ce ! /eady circulation ?r\gh a sy/em ( clos$ tubes4 ,9 ord] to und]/& ?is passage ( ! blood1 x is necess>y to keep 9 m9d ! great pr9ciple ) :i* hydro/atics supplies u1 viz41 t a liquid always fl[s f a region ( high to a region ( l[] pressure4 ,! problem ( ! vascul> sy/em is1 !re=e3 ,h[ c ! pressure )9 a r+ ( tube be s arrang$ z to ma9ta9 a regul> fl[ always 9 ! same direction8 ,let u beg9 ) ! /ructure ( ! sy/em4 ,! tube ?r\gh :i* ! blood fir/ passes on leav+ ! he>t is compos$ ( f\r di/9ct & ess5tial elem5ts3 ,a l9+ ( endo!lial cells1 :i* we ne$ n discuss at l5g?2 a ma9 sub/ance ( t\gh :ite fibr\s connective tissue2 ela/ic fibres & muscle fibres1 ! two la/ arrang$ 9 ! sub/ance ( ! connective tissue4 ,all ^! p>ts are pres5t 9 ! ma9 art]ies :i* leave ! he>t1 b 9 ! f9e me%work ( capill>ies to :i* ! art]ies give rise by repeat$ bran*+s !re is no?+ left ( ! out] coats1 only ! l9+ ( endo!lial cells sep>at+ ! blood f ! organ trav]s$4 ,9 ! ve9s :i* ^! capill>ies unite to =m1 ! connective-tissue %ea? reappe>s1 & also "s muscle2 b ! ela/ic coat is q abs5t4 ,! he>t is really a d\ble coil ( ! tube 7see ,diagram #ab71 9 :i* ! muscul> coat is pr$om9ant1 & is divid$ into f\r *amb]s by ! valves1 :i* insure ! blood fl[+ 9 ! "r direction :5 x contracts4 7,see ,diagram #cc47 ,illu/ration3 ,,diagram #cc4--,,s*eme ,,( ,,circulation ,! way 9 :i* ^! /ructures "w is z foll[s3 ,two ( ! *amb]s ( ! he>t 7! auricles7 receive blood f ! ve9s1 & :5 full sudd5ly contract1 driv+ _! cont5ts into ! o!r two *amb]s 7! v5tricles74 ,! blood does n run back into ! ve9s1 al?\gh ! pressure 9 !m is v l[ & !re are no valves to prev5t x1 because !re is /ill less pressure 9 ! v5tricles1 & also because ! ve9s ent] ! auricles obliquely1 & ! t5d5cy ( ! increas+ pressure is to close _! orifices4 ,hav+ dis*>g$ ! blood into ! v5tricles1 ! auricles relax1 & ! pressure )9 be+ a m9us quantity1 !y are spe$ily fill$ ) blood f ! ve9s1 blood n be+ able to return aft] ent]+ ! v5tricles1 z valves close automatically to prev5t x4 ,/imulat$ by ! blood di/5d+ !m1 ! v5tricles !n contract simultane\sly l ! auricles1 only ) mu* great] =ce3 = ! "r v5tricle has to drive ! blood all ?r\gh ! vessels p]vad+ ! lungs back to ! left auricle2 :il/ ! left v5tricle1 :i* is proportionately /rong] ?an ! "r1 has to s5d its cont5ts to ! fur!/ extremities ( ! body4 ,!y !n relax1 9 ord] t conditions ( _! int]nal pressure may fav\r ano!r infl[ f ! auricles1 return ( blood f ! art]ies be+1 z 9 ! prec$+ case1 prev5t$ by valves4 ,! pressure 9 ! art]ies dur+ life is always fairly high2 inde$1 ! v5tricles h to get up a consid]able =ce be=e ! valves lead+ f !m w op54 ,! result ( ?is is n only t ! blood is driv5 along !m ) a ru%1 b also t !y are slightly di/5d$ at ea* beat2 & s1 ow+ to ! ela/icity ( _! walls1 ! blood cont9ues to fl[ =w>ds ev5 betwe5 ! beats ( ! he>t4 ,! re/ ( ! j\rney is q simple2 ! pressure 9 ! capill>ies is l[] ?an 9 ! art]ies1 & ! pressure 9 ! ve9s l[] ?an 9 ! capill>ies1 & l[] 9 ! ve9s1 too1 z !y approa* ! he>t1 till1 :]e !y jo9 ! auricle1 x is actually m9us1 & ! blood has no o!r c\rse op5 to x b to return to ! auricle4 ,x looks z ?\gh accid5ts might happ5 9 ! ve9s ow+ to !re be+ s l[ a pressure !re to direct ! curr5t1 b ?is is prev5t$ by ! pres5ce ( valves at int]vals1 to /op any return4 ,! rate at :i* ! blood travels is ano!r po9t :i* has an important be>+ on ! nutrition4 ,x does its "w--i4e41 gives out nutrim5t & picks up refuse--:il/ fl[+ ?r\gh ! capill>ies2 s "h "o f9ds t x moves sl[ly4 ,on ! o!r h&1 ! soon] x rea*es !m ! bett]1 s x races fa/ ?r\gh ! art]ies4 ,f9ally1 its return to ! he>t ne$ n be delay$1 s x is quick5$ up aga9 ?r\gh ! ve9s4 ,! pr9ciple by :i* ?is v>iation 9 ! rate ( fl[ is obta9$ is simple & inevitable4 ,if a tube ?r\gh :i* liquid is fl[+ is n ! same size all ! way along1 ! liquid w be f\nd to fl[ fa/] 9 ! n>r[ p>ts ?an 9 ! wid] ones4 ,n[1 9 bran*+1 ! art]ies d n keep becom+ small] 9 regul> proportion1 & ! result is t ! capill>ies h collectively a diamet] five hundr$ times l>g] ?an ! aorta2 h5ce ! blood fl[s ?r\gh !m only "o-five-hundr$? ( ! pace at :i* x leaves ! he>t4 ,b 9 unit+ aga9 to =m ! ve9s _! cross-section is r$uc$ once m1 s t t ( ! l>ge ve9s ne> ! he>t is only two & a half times l>g] ?an t ( ! aorta1 & h5ce a fl[ only two & a half times sl[] results4 ,! pace ( ! blood-/ream mu/ dep5d1 obvi\sly1 on ! pressure ( ! blood 9 ! art]ies4 ,?is pressure is alt]$ ei!r by *ang+ ! rapidity ( ! he>t-beat or ! diamet] ( ! art]ies1 :i* are capable ( consid]able v>iation ow+ to _! muscul> coat4 ,! regulation ( ! blood-pressure is manag$ by ! n]v\s sy/em1 s does n belong "h1 & we may leave x aft] m5tion+ "o or two facts4 ,high pressure is due to a l>ge quantity ( blood be+ 9 ! art]ies1 & ?is may be due ei!r to ! rapidity ) :i* x is inject$ by ! he>t or to ! r$uc$ capacity ( ! bloodvessels !mselves4 ,high pressure1 due to ! latt] cause1 ?r[s a great /ra9 ^u ! he>t1 ow+ to ! h>d "w x has 9 pump+ blood into ! art]ies2 ) a l[ pressure ! he>t beats feebly1 hav+ less resi/ance to ov]come4 ,blood-pressure c be rais$ by /imulat+ ! muscul> coat & r$uc+ ! capacity ( ! bloodvessels1 & l[]$ by caus+ ! he>t to beat m sl[ly or by remov+ blood f ! body4 ,?is latt] op]ation 0 a fav\rite way ) doctors ( ! old s*ool2 b z our k ( physiology1 & ) x our control ov] ! vital functions1 increases1 su* crude & h]oic rem$ies are able to be replac$ by o!rs :i* are less dang]\s4 ,,vi4 ,comp>isons are rightly reg>d$ z objectionable1 s x w\ld h>dly be safe to say t ! gr\p ( movem5ts ^: prim>y object is fill+ ! lungs1 & :i* we mu/ /udy next1 is ! mo/ important 9 ! body1 especially :5 we h j be5 speak+ ( ! circulation1 :i*1 h[ev]1 w\ld be ( b little use if ! blood c\ld n be oxidiz$2 b we c at lea/ say t its importance _c be ov]rat$1 s f>-rea*+ are its effects4 ,! lungs are1 z we h describ$ !m above1 a pair ( delicate membran\s sacs connect$ by a tube1 ! tra*ea1 ) ! alim5t>y canal1 f :i* !y orig9ally budd$ out4 ,!y are subdivid$1 ?\gh h[ we ne$ n describe 9 detail1 into a va/ numb] ( small comp>tm5ts1 s z to give ! maximum surface 9 ! space accord$ !m1 & ! :ole some:at resembles a clu/] ( grapes1 ! /alks be+ ! bran*es ( ! tra*ea4 ,! membran\s p>ts are p]vad$ by an ela/ic network1 envelop+ ! comp>tm5ts 9 su* a way t x w\ld r$uce !m p]man5tly to ! resemblance ( a bun* ( rais9s r ?an grapes1 7 x n t !y are enclos$ 9 an airtight box--! ?orax--f ! walls ( :i* !y _c %r9k )\t caus+ a vacuum4 ,ow+1 h[ev]1 to ! latt] arrangem5t & ! tra*ea be+ op5 to ! ext]nal _w1 !y are always m or less di/5d$ ) air4 ,! ?orax1 :i* !y ?us mu/ always exactly fill1 is a conical-%ap$ box1 its walls be+ ! ribs1 & its floor a %eet ( muscle kn[n z ! diaphragm4 ,x conta9s1 besides ! lungs1 only ! he>t & l>ge bloodvessels4 ,! problem1 !re=e1 ( draw+ air into ! lungs & 7aft] ! gase\s int]*ange describ$ 9 ,essay ,,ii41 ,section ,,iv41 has tak5 place7 ( expell+ x aga91 becomes solely a matt] ( increas+ & decreas+ ! capacity ( ! ?orax4 7,see ,diagram #cd47 ,?is c be done 9 two ways3 ! diamet] ?r\gh ! ribs c be increas$1 or ! diaphragm c be pull$ d[n1 increas+ its dep?4 ,actually1 bo? ^! me?ods come into play toge!r4 ,diagram #ce w probably give a bett] idea ( h[ ?is is done ?an c\ld easily be convey$ by a v]bal description4 ,an attempt is "h made to %[ ! action ( ! ribs & ! diaphragm--fir/1 ( ea* sep>ately1 !n ( ! two comb9$4 ,! ela/icity ( ! lungs !mselves is suffici5t to drive out ! tidal air if ! diaphragm & ! muscles ( ! ribs are relax$1 ?\gh 9 h>d brea?+ a muscul> movem5t may depress ! ribs & a contraction ( ! abdom9al muscles =ce up ! diaphragm4 ,illu/ration3 ,,diagram #cd4--,,model 7,,adapt$ ,,f ,,ru!r=d7 ,,= ,,%[+ ,,h[ ,,! ,,lungs ,,are ,,fill$ ,,) ,,air ,,by ,,alt]+ ,,! ,,size ,,( ,,! ,,?orax4 ,b ?\gh ! prim>y object ( rais+ ! ribs & depress+ ! diaphragm may be to fill ! lungs1 its second>y influ5ce ^u ! trunk z a :ole is h>dly less important4 ,! effect ^u ! circulation is pr(\nd4 ,! comp>tm5ts ( ! lungs are envelop$ 9 innum]able capill>y bloodvessels1 &1 z ^! lie ar\nd & betwe5 !m 9 ! cavity ( ! ?orax1 !y mu/1 :5 brea? is drawn 91 be subject$ to a negative pressure be=e ! lung itself1 & be ! fir/ to exp]i5ce a positive pressure :5 ! air is expell$4 ,"h1 aga91 a diagram is ! be/ explanation4 7,see ,diagram #cf47 ,! pulmon>y vessels1 moreov]1 are n ! only ones influ5c$4 ,! read] :o att5tively exam9$ ,diagram #ac mu/ h be5 /ruck by ! peculi>ities ( ! circulation ?r\gh ! sple51 inte/9e & liv]1 & ! ob/acles :i* ?is repeat$ break+ up into f9e vessels mu/ (f] to ! fl[ ( blood1 z describ$ 9 ,section ,v4 ( ?is essay4 ,illu/ration3 ,,diagram #ce4--,,%[+ ,,h[ ,,! ,,capacity ,,( ,,! ,,?orax ,,is ,,increas$ ,,by ,,rais+ ,,! ,,ribs ,,& ,,depress+ ,,! ,,diaphragm4 ,illu/ration3 ,,diagram #cf4--,,model ,,= ,,%[+ ,,effect ,,( ,,movem5ts ,,( ,,! ,,?orax ,,on ,,! ,,pulmon>y ,,circulation4 ,! liv] =ms ! crux ( ! situation4 7,see ,diagram #cg47 ,a ve9 c>ry+ blood f ! inte/9e & sple5 is brok5 up into f9e capill>ies to pass ?r\gh t organ1 & ! pressure 9 ?is ve9 is extremely l[4 ,h[ is a suffici5tly rapid fl[ ( blood to be ma9ta9$8 ,! answ] to ?is riddle is be/ giv5 by ,diagram #ch1 :i* %[s h[1 by ! contraction ( ! diaphragm at ea* brea?1 ! l>ge ve9s ent]+ ! he>t are subject$ to a negative pressure :i* draws blood out ( ! liv]1 :ile1 simultane\sly1 t organ is squeez$ & ! blood x conta9s =c$ out4 ,obvi\sly ?is natural pump influ5ces n only ! fl[ ( blood1 b also t ( ! lymph1 & :at 0 said ab\t ! hepatic vessels also holds good = ! ?oracic duct1 up :i* ! lymph1 ri* ) fat absorb$ f ! inte/9e1 passes to be empti$ into ! l>ge ve9s ne> ! he>t4 ,s1 ?\gh vig\r 9 ! action ( ! diaphragm is m fav\rable to heal? ?an necess>y to life1 deep brea?+ is an ess5tial factor 9 ! well-be+ ( ! body4 ,illu/ration3 ,,diagram #cg4--;,a ,,diagrammatic ,,view ,,( ,,! ,,circulation ,,?r\gh ,,! ,,organs ,,^u ,,:i* ,,! ,,diaphragm ,,presses ,,:5 ,,x ,,desc5ds4 ,illu/ration3 ,,diagram #ch4--;,,illu/rat+ ,,! ,,influ5ce ,,( ,,! ,,diaphragm ,,^u ,,! ,,circulation ,,?r\gh ,,! ,,visc]a4 ,,vii4 ,all ! movem5ts z yet describ$ are absolutely necess>y to ! cont9uation ( life2 !y are1 moreov]1 indep5d5t ( ! ef=ts ( ! w4 ,b !re rema9s yet ano!r k9d ( movem5t )\t :i* ! body1 left to itself1 w\ld die4 ,?is is ! movem5t ( ! limbs--organs by :i* ! body is able to move f "o place to ano!r1 to capture its food & convey x1 vi ! m\?1 to its /oma*--9 a ^w1 to satisfy its *emical & physical ne$s4 ,to und]/& h[ ! limbs "w requires a k ( _! anatomy1 = :i* we h n "t or space "h2 b ! pr9ciple ?r\gh\t is t ( a sy/em ( lev]s1 ! bones1 work$ by ! volunt>y muscles4 ,"h1 z be=e1 a diagram w probably be f\nd to convey m ?an c\ld ev] be express$ 9 words4 7,see ,diagram #ci47 ,! diagram repres5ts v r\ghly1 b x is hop$ v pla9ly1 ! ma9 pr9ciple ( ! elb[-jo9t2 b = an exact k ( ! me*anism ( ! jo9t1 & ! comp>ative /ra9 ^u1 & !re=e /r5g? (1 ea* muscle1 ! read] mu/ consult "s "w on anatomy4 ,he w !re f9d1 if he goes on to read ! description ( ! h&1 :at a wond]ful precision1 complexity1 & am\nt ( movem5t c be obta9$ by v>iations ( ?is simple device4 ,illu/ration3 ,,diagram #ci4--;,,diagram ,,( ,,! ,,arm4 #a1 ,lift+2 #b1 press+4 ,"h1 h[ev]1 we mu/ leave ! /udy ( ! mann] & object ( ! bodily movem5ts1 & proce$ to inve/igate ! f> m intricate "q ( h[ !y orig9ate & are controll$4 ,,essay ,,iv4 ,,! ,,n]v\s ,,sy/em4 ,i4 ,n[ comes ! f9al problem4 ,protoplasm =ms a /ructure always *ang+1 always mak+ good its wa/e by *emical action ^u raw mat]ial1 always captur+ raw mat]ial or 9 se>* ( x1 always1 :5 x exi/s 9 l>ge quantities1 & ! lab\r is !re=e divid$ betwe5 _m cells1 economically apportion+ ! "w & ! spoils4 ,h[ is x t all ! actions1 *emical z well z physical1 ( a va/ numb] ( cells compos+ a l>ge body are1 no matt] h[ complicat$1 always h>moni\s1 & always ) purpose direct$ to ! advantage ( ! :ole animal8 ,9 ! fir/ essay 9 ?is book we discuss$ ! ph5om5on ( life1 & describ$ briefly ! *emical & physical peculi>ities ( protoplasm4 ,^! 9 ! two succe$+ essays we h gone into m fully2 b !re is "o *>act]i/ic ( t int]e/+ sub/ance :i* yet rema9s = u to exam9e 9 specializ$ cells1 viz41 its extreme read9ess to respond to *anges 9 its environm5t4 ,9 ,essay ,i4 we saw t *emical ag5ts1 light1 heat1 electricity1 etc4--_h a def9ite effect ^u protoplasm1 & t1 ?\gh !y might influ5ce diff]5t k9ds 9 diff]5t ways1 ! effect 0 nev]!less inv>iable2 9 a ^w1 ! response ( protoplasm to circum/ances is automatic4 ,b ! mo/ rem>kable ?+ ab\t ?is is t ! response is n conf9$ to ! protoplasm actually affect$1 b is transmitt$ to t ne>e/ to ! "p /imulat$1 & aga9 pass$ on to t beyond1 s t a wave ( excitation passes ?r\gh ! :ole mass1 n /opp+ till x has rea*$ ! extreme conf9es ( ! cell4 ,x may ev5 pass beyond ^! & set up activity 9 neighb\r+ cells4 ,! p[] ( conductivity once grasp$1 x may easily be se5 t c]ta9 cells1 by specializ+ 9 ?is direction & adapt+ _! %ape to ! ne$s ( ! body1 might by ?r[+ out long ?reads to rea* di/ant p>ts set up an organic sy/em ( telegraphy4 ,! organs develop$ = ! control ( ! body owe _! orig9 to ! out] lay]4 7,see ,diagram #e47 ,?is 0 only to be expect$4 ,9 ! second essay1 9 :i* we treat$ ( ! *emi/ry ( ! body1 we1 ( c\rse1 t\*$ ^u all ?ree lay]s f :i* ! body is built up2 b ! "o :i* *iefly occupi$ our att5tion 0 ! inn]mo/ lay]1 :i* is s admirably arrang$ z a *emical laboratory4 ,9 ! ?ird essay we dealt *iefly ) ! middle lay]1 :i* bo? by its position & its bulk might h be5 guess$ to be ! f\ndation ( mo/ ( ! motor organs4 ,n[ t we h come to ! organs ( p]ception & transmission ( impressions1 x is only natural to expect t !y %\ld be specializ$ f ! cells already 9 contact ) ! ext]nal _w1 & :i*1 s9ce !y =m ! envelope ( ! animal1 mu/ all[ all su* /imuli z rea* ! subjac5t motor lay] to pass ?r\gh !m4 ,hi!rto we h n dealt at great l5g? ) ! developm5t ( ! organs ^: functions we h be5 describ+1 ei!r f ! po9t ( view ( ! embryologi/ or ! evolutioni/4 ,nor h we sp5t mu* "t ^u _! gross anatomy4 ,) ! n]v\s sy/em we mu/ proce$ r diff]5tly2 = to und]/& h[ its high] functions c be p]=m$ !y mu/ be trac$ f _! orig9 /ep by /ep1 :ile _! complexity is l>gely ve/$ 9 ! /ructure ( special organs4 ,! way 9 :i* ! n]v\s sy/em 0 evolv$ is %[n 9 ,diagram #e4 ,orig9ally1 no d\bt1 ! cells ( ! out] lay]1 :5 ! latt] 0 9 its simple/ =m--t is to say1 only "o cell ?ick1 n sev]al1 z x is 9 our sk9--w\ld1 :5 influ5c$ 9 any way directly call =? ! activity ( ! motor cells ly+ b5ea? !m4 7,see ,diagram #dj1 ,fig4 #a47 ,9 ,fig4 #b1 h[ev]1 we see "o cell ( ! out] lay] becom+ specializ$4 ,x has ?r[n out a process above ! surface ( ! sk9 ! m readily to cat* impressions1 & has s5t ano!r d[n into ! body ! bett] to di/ribute !m4 ,diagram #da1 ,fig4 #a %[s ! n]ve cell at a fur!r /age4 ,! pr9ciple is ! same1 b ! cell is remov$ to a saf] place4 ,9 ,fig4 #b x is n expos$ to ! outside _w at all1 b by receiv+ its impulses second-h& f sev]al cells ! same "w is done ) great] economy & uni=mity4 ,"s ( ! special s5se organs are /ill develop$ 9 ?is way4 ,illu/ration3 ,,diagram #dj4--,,%[+ ,,orig9 ,,( ,a ,,n]ve ,,cell4 ,illu/ration3 ,,diagram #da4--,,%[+ ,,! ,,developm5t ,,( ,a ,,n]ve ,,cell4 ,once ! n]ve cell is develop$ & safely %ift$ into ! int]ior ( ! body1 x is clo!d ) a protect+ feltwork ( connective tissue1 & ! n]ve fibres are also surr\nd$ by connective-tissue cells :i* secrete ar\nd !m ! fatty sub/ance :i* makes n]ves look :ite4 ,su* is ! n]ve cell or int]m$i>y betwe5 ! _w & ! muscles2 b !nce to h>moni\s movem5t 9 a body ) complex organs capable ( v>i$ actions is a long /ep4 ,to obta9 precision & uni=mity ?r\gh\t ! body1 all ! impressions receiv$ mu/ be collect$ & balanc$1 & /imuli1 ! correct outcome ( ?is balanc+1 mu/ be transmitt$ to ! muscles1 gl&s1 etc41 ^: activity circum/ances require4 ,! way 9 :i* cells ( ! out] lay] become enclos$ to =m a c5tral n]v\s sy/em is %[n 9 ,diagram #e2 b its developm5t w be bett] se5 9 ! figures ( ,diagram #db4 ,illu/ration3 ,,diagram #db4--,,to ,,illu/rate ,,! ,,developm5t ,,( ,,! ,,n]v\s ,,sy/em4 ,illu/ration3 ,,diagram #dc4--;,,cross-,,section ,,( ,,! ,,sp9al ,,cord1 ,,%[+ ,,h[ ,,x ,,gives ,,(f ,,n]ves4 ,illu/ration3 ,,diagram #dd4 ,?is diagram %[s h[ c]ta9 cells ( ! out] lay] are budd$ (f & transf]r$ to a safe place )9 ! body4 ,9 ?is position ! cells are fur!r develop$1 ?r[+ out "o long fibre1 :i* goes to "s di/ant organ ( ! body1 & %ort fibres1 :i*1 ?\gh !y d n jo9 ^? ( o!r cells & become cont9u\s1 closely int]lace & put !m into communication4 ,!y are also sep>at$ f "o ano!r by connective tissue1 :i* supports !m1 hold+ !m susp5d$ ) only _! fibres approa*+ "o ano!r 7,diagram #dc74 ,diagram #dd %[s h[ ! bone :i* replaces ! support+ rod 7see ,diagram #f7 ?r[s an ar* r\nd ! feltwork ( connective tissue 9 :i* ! n]ve cells are susp5d$1 giv+ !m /ill fur!r protection4 ,x w be notic$ 9 ! figures ( ,diagram #db1 :i* is full] ?an ,diagram #e1 t !re are ?ree ( ^! buds--"o c5tral & two lat]al4 ,! c5tral "o becomes a tube runn+ ! :ole l5g? ( ! animal1 :ile ! lat]al buds =m solid clu/]s or ganglia1 arrang$ 9 pairs at int]vals beside x 7see ,diagram #de74 ,fibres f ^! ganglia g to ! sk91 & br+ to ! n]ve cells in=mation f ! outside _w1 :i* !y duly pass on to ! cells ( ! c5tral column4 ,! cells ( ! c5tral column1 :5 set 9 motion by ! ganglion cells1 s5d out impulses to ! muscles1 ^: contraction is necess>y to p]=m ! movem5t :i* circum/ances indicate4 ,a movem5t br\ght ab\t 9 ?is way is call$ reflex4 ,illu/ration3 ,,diagram #de4--;,,c5tral ,,n]ve ,,tube ,,& ,,ganglia4 ,! reflex movem5ts are1 h[ev]1 n q ! simple/4 ,= in/ance1 ! food is mov$ along ! alim5t>y canal by ! contraction ( two sets ( muscle fibres--an out] longitud9al coat & an inn] circul> "o4 ,betwe5 ^! two coats are "s n]ve cells1 :i* are ?r[n into activity by ! pres5ce ( food & ! iron comp\nds ( ! bile secret$ by ! liv] 9 ! tube4 ,^! sympa!tic cells d n s5d _! impulses to any c5tre = exam9ation1 b at once /imulate ! muscle fibres betwe5 :i* !y lie1 !reby produc+ ! p]i/altic movem5ts we h already describ$4 ,yet x %\ld be rememb]$ t1 ?\gh ^! cells act indep5d5tly ( ! c5tral n]v\s sy/em1 !y are "u its control1 & c1 if ne$ be1 h _! action modifi$ = ! b5efit ( ! body z a :ole4 ,= conv5i5ce' sake1 we _h bett] "h specify ! *ief k9ds ( n]v\s action4 ,fir/ !re is :at we may call ! imm$iate n]ve action1 su* z t we h j be5 describ+2 secondly !re is reflex action1 ! c5tres = :i* are 9 ! sp9al cord & ! base ( ! bra92 & ?irdly !re is volunt>y movem5t1 :i* arises out ( ! int]action ( c5tres 9 ! hemisph]e ( ! bra91 :]e ! mo/ complex ma*9]y ( all is kept4 ,,ii4 ,( ! fir/ k9d we ne$ say no m4 ,! in/ance ( p]i/altic movem5t illu/rates x suffici5tly2 s we c at once beg9 a m c>eful exam9ation ( reflex action4 ,! simple/ in/ance ( reflex action may be tak5 f ! s*oolroom4 ,if a boy sudd5ly /icks a p9 into an unsuspect+ s*oolfell[1 ! latt] inv>iably />ts1 & frequ5tly lets fall an exclamation also4 ,9 ?is case ! pres5ce ( an injuri\s ag5cy is report$ to ! ne>e/ motor c5tre1 :i* is 9 ! sp9al cord1 & ?is automatically convulses ! body1 j]k+ ! limb out ( dang]4 ,?is is reflex movem5t2 ! n]ve fibre1 :i* conveys an intimation ( ! injuri\s influ5ce1 is a prolongation1 or really two prolongations1 ( a sp9al ganglion cell4 7,see ,diagram #df47 ,! ne> end ( ?is fibre1 :i* ent]s ! cord1 has sev]al bran*es4 ,"s run a little way up ! cord1 & "s a little way d[n1 s z to communicate ) sev]al motor cells2 b "o bran* runs "r up ! cord1 & s5ds ! message on to ! bra94 ,our outrag$ s*oolboy />ts a fraction ( a second be=e he is consci\s ( ! pa9 ( be+ prick$1 & ?is fir/ response is involunt>y & unv>y+2 ! s5sation1 h[ev]1 is report$ to 8 bra91 & ! work+s ( t wond]ful organ are less easy to pr$ict4 ,x leads to 8 tak+ /ock ( ! aggressor1 on ! /r5g? ( :i* he decides :e!r x is safe to attempt a reprisal1 &1 if s1 9 :at =m x w be mo/ effective & lea/ likely to attract ! ma/]'s att5tion4 ,?is knotty po9t settl$1 ! motor cells ( ! bra9 s5d d[n messages to ! motor cells ( diff]5t p>ts ( ! sp9al cord1 & ^! 9 turn set ! necess>y muscles 9 motion = deliv]+ a surreptiti\s kick or aim+ a spla% ( ink1 z ! case may be4 ,?is is volunt>y movem5t4 ,illu/ration3 ,,diagram #df4--;,,evolution ,,( ,a ,,sp9al ,,ganglion ,,cell4 ,illu/ration3 ,,diagram #dg4--,,s*eme ,,( ,,! ,,c5tral ,,n]v\s ,,sy/em4 %[s ! pa? tak5 by an impulse 9 reflex action4 %[s ! pa? = a volunt>y action4 ,! diff]5ce betwe5 reflex & volunt>y movem5t is1 z may be se5 f ! above in/ances1 v mu* a matt] ( degree2 b we _h bett] leave a comp>ison betwe5 !m1 & any discussion z to ! ext5t to :i* ! manife/ations ( consci\sness are automatic1 until we h f9i%$ describ+ reflex movem5t1 & set =? ! little we "k ab\t volunt>y movem5t4 ,"t & space =bid a complete li/ ( reflex movem5ts4 ,! foll[+ are1 h[ev]1 a few typical examples ( h[ ! body is automatically made to p]=m su* acts z are necess>y1 & ( h[ su* z d n require delib]ation are br\ght ab\t )\t tax+ ! intellect4 ,a reflex action :i* is unpleasantly famili> is ! c\gh1 also ! some:at simil> ph5om5on ( ! sneeze4 ,9 ?is case1 a =eign body :i* ob/ructs ! w9dpipe1 or causes irritation to ! membrane l9+ ! nose1 is1 on be+ report$ at ! sp9al cord1 incont95tly bl[n out by an explosive bla/ ( air f ! lungs4 ,an organ :i* is v important1 & at ! same "t v s5sitive--viz41 ! eye--has _m protective reflexes4 ,! ext]nal surface ( ! eye is cov]$ by a v delicate membrane1 :i* mu/ be kept moi/ & scrupul\sly clean4 ,:5ev] ?is membrane gets 9 ! lea/ dry1 or any du/ falls on x1 ! eyelids are clos$ = a mom5t1 !reby ba?+ x ) ! secretion ( ! te> gl&s4 ,few p are aw>e1 ,i ?9k1 t !y bl9k _! eyes on an av]age twice e m9ute4 ,! eyes are also clos$ q involunt>ily by a reflex :5 any dang] ?reat5s !m--= in/ance1 a sudd5 dazzl+ light1 a /rong w9d1 or a bl[ aim$ at ! face2 & if any =eign sub/ance--say a fly--does get into "o ( !m1 ! secretion ( ! te> gl&s is enorm\sly increas$ to wa% x out4 ,! size ( ! pupil1 aga91 is q involunt>ily1 i4e41 reflexly1 alt]$ 9 proportion to ! /r5g? ( ! light4 ,reflex actions are1 h[ev]1 by no means only protective4 ,! act ( swall[+ is reflex4 ,s is ! secretion ( ! dige/ive gl&s :5 ! l9+ membranes ( ! /oma* are /imulat$ by ! pres5ce ( food4 ,! v act ( /&+ dep5ds on ! reflex pr9ciple1 ! t5d5cy ( ! body to collapse & fall be+ unconsci\sly p]ceiv$ & correct$ by ! sp9al cord4 ,walk+ is also a reflex action4 ,x may be object$ t we ?9k ab\t walk+1 & d s ) int5tion2 b x is ( common exp]i5ce t we c walk along #8?9k+ ( some?+ else1' & ! way 9 :i* an intellectual ?\gh abs5t-m9d$ man w run into p1 *>ge lamp-po/s1 trip ov] /eps1 & tread ^u dogs1 is suffici5t to absolve ! organ ( ?\ght & int5tion f any %>e 9 ! p]=mance4 ,! blood-pressure is also automatically regulat$1 bo? ! diamet] ( ! bloodvessels & ! frequ5cy ( ! he>t-beat be+ "u reflex control2 & we may1 z a f9al in/ance ( reflex action1 describe "o ( ,nature's mo/ p]fect & m]ciful contrivances--fa9t+4 ,suppose a man receives a sev]e w\nd--say1 has 8 h& /ruck (f by a sword--! %ock to 8 sy/em causes an imm$iate dilatation ( ! l>ge bloodvessels ( ! abdom52 ?is results 9 a great fall ( blood-pressure1 & ! he>t1 f9d+ t x has mu* less resi/ance to ov]come1 slack5s its beats s t soon ! fl[ ( blood is v sl[ inde$4 ,h5ce1 x has "t to clot ov] ! w\nd1 & ! man does n ble$ to dea?4 ,incid5tally1 ! feeble curr5t ( blood is insuffici5t to keep ! mo/ delicate organ ( ! body1 ! bra91 9 its normal /ate ( activity1 & ! man is reliev$ f 8 pa9 by unconsci\sness1 :i* passes (f :5 ! he>t aga9 quick5s its beat4 ,x is p]haps ne$less to rem>k t fa9t+ fits are n always & only caus$ by fle% w\nds2 !y may be due to weakness or o!r causes4 ,n[1 if we consid] ! in/ances quot$ above1 we are able to d$uce a few g5]al pr9ciples f !m4 ,9 ! fir/ place1 x may be notic$ t reflex action compels u to p]=m ! movem5ts necess>y to our exi/5ce :e!r we l x or no4 ,x is n = u to decide :e!r we w brea! or n4 ,we mu/4 ,! /ronge/-will$ man :o ev] liv$1 no matt] h[ mu* a philosoph]1 c\ld n commit suicide by hold+ 8 brea?1 z ,cato boa/$ he c\ld4 ,directly he lo/ consci\sness1 suppos+ he manag$ to hold out till !n1 ! ta9t$ blood ba?+ ! respiratory c5tre w\ld awake x to activity1 & he w\ld />t brea?+ afre%4 ,aga91 x is noticeable t _m ( ^! actions c\ld n possibly be p]=m$ by a volunt>y ef=t4 ,we c1 to a c]ta9 ext5t1 regulate ! dep? & frequ5cy ( our brea?+1 & we c bl9k our eyes volunt>ily2 b an av]age man w\ld be q at a loss :at to d if ask$ to make ! pupil ( 8 eye dilate & contract1 ! gl&s ( 8 /oma* secrete1 or 8 he>t alt] its rhy?m4 ,x is a famili> fact t "s reflex actions c be alt]$ by an ef=t ( ! w2 9 o!r words1 an impulse f a bra9 cell w prev5t a n]ve cell 9 ! sp9al cord f dis*>g+4 ,b x is an equally famili> fact t ) cont9u\s /imulation ! impulses accumulate & ultimately ov]come ?is resi/ance4 ,mo/ p h at "s "t or o!r /riv5 to resi/ ! incl9ation to c\gh1 consequ5t ^u a tickl+ s5sation 9 ! ?roat1 & "k t !re comes a "t :5 !y c re/ra9 !mselves no long]4 ,?is is because ! accumulat$ /imuli f ! ?roat1 hav+ rea*$ a great] /r5g? ?an ! prohibitive impulse f ! bra91 succe$ 9 compell+ ! cells 9 ! cord to dis*>ge4 ,la/ly1 reflexes c be le>nt4 ,:5 a "y *ild fir/ endeav\rs to /& upright1 ! s5sation ( fall+ is d\btless convey$ to ! bra91 & ?\ght tak5 ( h[ ! erect position c be ma9ta9$4 ,b x is n until aft] _m exp]im5ts & failures t ! bra9-cells c s5d messages to ! "r cells 9 ! cord1 & ^! set ! necess>y muscles 9 motion4 ,exp]i5ce tea*es :at mu/ be done1 & con/ant practice ev5tually enables ! sp9al cord to act = itself )\t ref]r+ = ord]s to ! bra94 ,x is on ! same pr9ciple t we le>n to ride ! bicycle4 ,at fir/ we h to devote our :ole att5tion to keep+ our balance1 b 9 a %ort "t we f9d we are do+ x ) our m9d free to contemplate ! sc5]y4 ,:at c be done by reflex action c only be appreciat$ by obs]v+ an animal f :i* ! bra9 has be5 remov$4 ,a frog :i* has be5 treat$ 9 ?is way--! op]ation1 x %\ld be said1 if p]=m$ "u an an/hetic c cause no pa91 ei!r at ! mom5t or aft]w>ds--w live = weeks--9 fact1 almo/ indef9itely--if prop] precautions be tak54 ,b x is an automaton pure & simple4 ,unless t\*$ x sits absolutely /ill4 ,if t\*$ x hops once or twice /raight ahead reg>dless ( ob/acles4 ,if plac$ 9 wat] x swims1 equally reg>dless ( ob/acles4 ,if turn$ on its back x imm$iately resumes its normal position4 ,if small *ips ( wood are plac$ on its back x kicks !m (f4 ,if ! table on :i* x is sitt+ be tilt$ x w crawl up ! incl9e until x rea*es a level4 ,b x w />ve 9 ! mid/ ( pl5ty1 hav+ lo/ all p[] ( ?\ght1 memory & p]ception4 ,if dilig5tly f$ by h& a frog1 a fi%1 or a bird w live = a long "t )\t any bra91 s9ce _! rep]toire ( movem5ts is small & mo/ly reflex1 & _! occasions = delib]at$ action comp>atively few4 ,b ! high] we get 9 ! scale ( life ! m ! bra9 takes ov] ! duties ( ! cord1 ! less automatic become ! great] numb] ( ! actions1 & h5ce ! m op5 does ! animal's conduct lie to moral criticism4 ,,iii4 ,we h n[ se5 h[ protoplasm exi/s 9 a l>ge body1 %>+ ! "w ( liv+ among/ specializ$ cells1 & h[ x responds z a :ole to ! influ5ces ex]t$ ^u x by its surr\nd+s4 ,! next ?+ to consid] is h[ x is situat$ ) reg>d to matt] :i* does n =m "p ( its own body2 h[ protect$ f1 & h[ put into communication )1 ! re/ ( ! univ]se4 ,) reg>d to ! =m]1 we h se5 t 9 ! s+le cells1 con/itut+ unicellul> organisms1 !re is always a b\nd+ membrane ( d5s] texture ?an ! re/ ( ! protoplasm4 ,z ! cell develops its capabilities1 we h a %ell or case ( non-liv+ matt] secret$ ar\nd x1 ) ap]tures = communication ) ! outside _w1 & increas+ly effective protection is provid$ z protoplasm1 :e!r 9 ! s+le cell or ! body1 leaves ! wat]1 & has to face ! inclem5cies ( t]re/rial life4 ,illu/ration3 ,,diagram #dh4--,,%[+ ,,! ,,=mation ,,( ,,! ,,sk94 ,illu/ration3 ,,diagram #di4--,,/ructure ,,( ,,sk94 ,9 ! s*ematic embryo 7,diagram #f7 & o!r diagrams conta9$ 9 ?is volume1 ! sk9 has s f> be5 repres5t$ z consi/+ ( a s+le lay] ( liv+ cells2 b we mu/ n[ admit t ! sk9 ( man is q diff]5t4 ,su* a cov]+ w\ld be no protection f heat1 cold1 or irritat+ *emicals1 :ile1 9 ord] to prev5t its dry+ up1 x w\ld h to be kept moi/ ) slime1 & we %\ld look v l frogs4 ,9 ord] t an adequate def5ce may be provid$ = ! body1 ?is lay] ( cells divides tang5tially1 =m+ two lay]s4 ,! inn] ( ^! two !n divides tang5tially aga91 & a second lay] is int]pos$ betwe5 ! inn]mo/ & t fir/ =m$4 ,! sk9 n[ consi/s ( ?ree lay]s1 & s ! process is repeat$ until x is sev]al lay]s ?ick4 7,see ,diagram #dh47 ,x is ! inn]mo/ & be/-n\ri%$ lay] :i* keeps divid+2 ! o!r lay]s1 z !y get pu%$ outw>ds1 are only rea*$ by a little lymph :i* filt]s betwe5 ! cells1 & are ev5tually />v$ ev5 ( t4 ,z !y get pu%$ away f ! divid+ lay]1 h[ev]1 !y set to "w to surr\nd !mselves ) a horny wall1 :i* ?ick5s & ?ick5s1 until ev5tually !re is h>dly any cell left4 7,see ,diagram #di47 ,f9ally ! cells die & ! horny envelopes =m a dead cuticle1 protect+ ! liv+ lay]s b5ea?1 & are ultimately sl\gh$ (f :5 _! successors are ready to replace !m4 ,illu/ration3 ,,diagram #ej4--,,%[+ ,,! ,,developm5t ,,( ,,hair4 ,n ev5 a horny lay] ( dead cells is1 h[ev]1 always suffici5t protection1 & ! gr[+ lay] has sometimes to supplem5t x by hair or fea!rs4 ,h[ hair is develop$ is %[n 9 ! accompany+ diagram 7#ej74 ,! gr[+ lay] s5ds a /r& /raight d[nw>ds into ! connective tissue1 :i* =ms ! basem5t ( ! sk94 ,! cells 9 ! middle ( ?is /r&1 :i* behaves l ord9>y sk91 are ! lea/ well n\ri%$1 & accord+ly die & leave a tube4 ,?is tube1 if no fur!r developm5t took place1 might become a sweat gl&2 b if x is to give rise to a hair x becomes cup-%ap$ at ! base1 enclos+ a small loop ( bloodvessel4 ,! cells j above ! capill>y1 be+ bett] n\ri%$ ?an ! re/1 gr[ m rapidly ?an _! neighb\rs1 & ! result is t a column ( cells :i* we "k z a hair pu%es its way up ?r\gh ! tube4 7,see ,diagram #ej47 ,?is out] lay] comes ev]y:]e betwe5 ! ma9 bulk ( ! body & ! out] _w4 ,hair & sweat gl&s d n by any means repres5t its only modifications4 ,tee? are =m$ f x 9 some:at ! same mann] z hair1 :ile we h already se5 t x gives rise to ! :ole n]v\s sy/em4 ,! next ?+ :i* we h to consid] is h[ k ( ! ext]nal _w rea*es ! c5tral n]v\s sy/em4 ,s5sations ( t\*1 temp]ature1 & pa9 are fairly easy to und]/&1 s9ce ! n]ves :i* convey su* impressions h num]\s end+s 9 ! sk94 ,end organs ( n]ves 9 ! jo9ts & muscles d\btless enable ! animal to p]ceive & e/imate /ra9 & resi/ance 9 mov+ or lift+ ?+s4 ,b ! p[] ( p]ceiv+ ! *emical peculi>ities ( ?+s2 light1 involv+ ! =mation ( visual images1 :i* we call see+2 s\nd2 & position & equilibrium1 x is n possible = ! :ole surface ( ! body to possess4 ,! pr9ciple ( division ( lab\r is ext5d$ to ! task ( p]ception z well z to t ( motion2 & cells1 ) _! prop]ty ( respond+ to light1 vibration1 *emical /imulation1 etc41 are gr\p$ toge!r to =m special organs1 connect$ ) ! c5tral n]v\s sy/em by special n]ves4 ,p]haps ! mo/ important factor :i* c influ5ce protoplasm is ! *emical nature ( its surr\nd+s2 & 9 ! fir/ essay1 on ! g5]al nature ( protoplasm1 we t\*$ ^u ! way 9 :i* x is drawn t[>ds "s sub/ances1 & repell$ by o!rs4 ,9 ! body !re are two sets ( cells deput$ to act = ! re/ 9 ?is p>ticul>4 ,"o set is situat$ 9 ! membrane l9+ ! nose1 ov] :i* ! air we brea! passes2 & ^! cells exam9e our gase\s surr\nd+s1 & w>n u1 by :at we t]m #8smell1' :e!r ! atmosph]e is fit = u or we _h bett] seek a pur]4 ,! o!r set is = ! exam9ation ( liquids4 ,aga9/ ^! we are protect$ by our sk91 &1 z we d n absorb any?+ ?r\gh x1 x is devoid ( ! p[] ( exam9+ ! ?+s x t\*es4 ,b ) our food x is diff]5t2 we mu/ h ! p[] ( te/+ t4 ,accord+ly1 !re are ,cu/oms (fic]s 9 our m\? 9 ! =m ( little gr\ps ( cells1 :i* report ^u ! liquids & solids moi/5$ by saliva1 & enable ! animal to reject p]nici\s imports4 ,?us1 ! /imulation ( a small portion ( ! protoplasm compos+ a body is transmitt$ ov] ! :ole1 & is able to awake 9 x ! necess>y response4 ,illu/ration3 ,,diagram #ea4 ,illu/ration3 ,,diagram #eb4 ,illu/ration3 ,,diagram #ec4 ,illu/ration3 ,,diagram #ed4 ,illu/ration3 ,,diagram #ee4 ,illu/ration3 ,,diagram #ef4 ,s mu* = ! *emical s5se organs2 !y are comp>atively simple4 ,b betwe5 a s+le cell1 :i* always makes t[>ds or always hurries out ( a ray ( light pass+ ?r\gh ! wat] 9 :i* x swims1 & an animal ) eyes capable ( recognis+ ! col\r1 %ape1 size1 & di/ance ( objects 9 space1 !re really does seem to be a wide gulf4 ,x is n1 h[ev]1 too wide to be bridg$4 ,aft] ! s+le-cell /age has be5 pass$1 & we h bea/s consi/+ ( an inn] lay] ( cells :i* is dige/ive 9 function1 & an out] lay] :i* is protective1 motor1 & s5sory1 ! p[] ( p]ceiv+ light is d\btless ve/$ 9 ! out] lay]4 ,:5 we get bea/s consi/+ ( ?ree lay]s progress+ along ! /raight pa? ( developm5t :i* leads to man1 we f9d ! out] lay] becom+ too opaque = ?is purpose1 & ! tor* is h&$ on to ! s5sory tube d]iv$ f x4 7,see ,diagram #e47 ,z m & m protection is requir$1 ! sk9 ?ick5s1 & ! neural tube comes to lie deep]1 z 9 ,diagram #ea4 ,9 ord] n to lose ! light altoge!r1 x has to ?r[ out buds1 :i* conc5trate 9 !mselves ! peculi> faculty ( p]ceiv+ x1 & at ! same "t little pits are =m$ 9 ! sk9 j ov] !m to help ! light to rea* !m4 7,see ,diagram #eb47 ,9 ,diagram #ec bo? ! n]v\s elem5ts & ! integum5t>y are develop+ _! possibilities2 & 9 ,diagram #ed a l>ge surface has be5 prep>$ = ! reception ( light1 & a l5s =m$ to focus ! rays ^u x4 ,diagrams #ee & #ef give ! conclud+ /ages 9 ! developm5t ( ! eye3 ! =mation ( ! cornea & its protect+ eyelids4 ,! two cavities are fill$ ) cle> liquids1 & ! :ole eyeball support$ by connective tissue4 ,s fasc9at+ is ev]y?+ connect$ ) ! eye t ! temptation to describe x 9 detail is great2 b 9 a book ( r\gh outl9es1 & 9 consid]ation ( ! _m important matt]s yet await+ _! turn1 we mu/ conf9e ourselves to briefly m5tion+ a few ( ! m important po9ts conc]n+ x4 ,! light is focuss$ by ! l5s ^u ! n]v\s curta9 at ! back1 & produces !re a picture1 z 9 ! photographic cam]a4 ,?us we p]ceive ! %ape ( objects4 ,! diff]5t rays ( ! spectrum affect diff]5t elem5ts 9 ?is curta9 or ret9a1 :]eby we get s5sations ( col\r4 ,f9ally1 ! cle>ness ( ! picture1 its size1 ! degree ( conv]g5ce ( ! two eyes1 & ! ef=t ( focuss+--= ! curvature ( ! surface ( ! l5s c be alt]$--enable u to e/imate ! size & di/ance ( an object4 ,& n[1 ?\gh x w\ld take volumes to d ju/ice to ! physiology ( vision1 we mu/ pass on to deal equally briefly ) ! functions ( t no less important organ1 ! e>4 ,! ess5tial "p ( ! e> is a membran\s bag1 =m$ by ! p\*+ 9 ( ! out] lay] ( cells--z %[n 9 ,figs4 #a1 #b1 & #c ( ,diagram #eg--:i* comes to lie 9 a bony *amb] b5ea? ! skull1 & assumes ! some:at complicat$ %ape depict$ 9 ,fig4 #d4 ,we h n "t1 nor is x = our purpose necess>y1 to trace all ! /eps 9 ! developm5t ( ! e>1 ei!r ext]nal or int]nal1 nor ne$ we sp5d mu* "t ^u its /ructure1 beyond indicat+ its position4 ,b its position1 :i* is %[n 9 ,diagram #eh1 mu/ be grasp$ 9 ord] to und]/& h[ x is influ5c$ by s\nd4 ,illu/ration3 ,,diagram #eg4--,,%[+ ,,developm5t ,,( ,,! ,,membran\s ,,labyr9? ,,( ,,! ,,e>4 ,u1 ,utricle2 ,c1 co*lea2 ,s1 saccule2 ,s4,c41 semicircul> canals4 ,x w be se5 t ! membran\s bag1 :i* is fitly t]m$ ! labyr9?1 is situat$ 9 a bony cavity :i* fits s closely z to be t]m$ ! bony labyr9? 7,c74 ,! membran\s labyr9? is fill$ ) a liquid1 call$ endolymph1 & ! bony labyr9? 7,c7 is also fill$ ) a liquid1 call$ p]ilymph1 9 :i* ! membran\s bag swims4 ,all ?is is call$ ! inn] e>4 ,! inn] e> communicates ) a second cavity--! middle e> 7,b7--by two ap]tures 9 ! bony wall1 :i* are clos$ by membranes4 ,! middle e> is full1 n ( liquid1 b ( air1 & is sep>at$ f ! ext]nal e>1 ! cavity m>k$ ,a1 :i* is op5 to ! ext]nal _w1 by ano!r membrane call$ ! tympanum1 or drum1 ( ! e>4 ,! middle e> is connect$ by a tube ) ! ?roat1 s t ! pressure ( ! air on bo? sides ( ! drum may be ! same4 ,illu/ration3 ,,diagram #eh4--,,%[+ ,,! ,,position ,,( ,,! ,,e>4 ,a41 ,out] e>2 ,b41 middle e>2 ,c41 inn] e>4 ,n[1 ! object ( ?is arrangem5t is t ! e> may be able to fulfil "o ( its pr9cipal duties1 namely1 ! p]ception ( s\nd4 ,s\nd1 z ! read] is d\btless aw>e1 is transmitt$ ?r\gh ! air z waves ( cond5sation & r>efaction1 due to ! sw++ backw>ds & =w>ds ( its p>ticles2 x resembles ! pass+ on ( a bump along a l9e ( trucks on ! railway :5 ! eng9e runs up aga9/ ! end "o prep>atory to c\pl+4 ,! magnitude ( ?is oscillation we p]ceive z ! l\dness1 ! frequ5cy z ! pit* ( a note4 ,n[1 :5 ! waves ( s\nd /rike aga9/ ! drum ( ! e>1 !y cause x to vibrate backw>ds & =w>ds also4 ,suppos+ !re 0 no middle e>1 & ! s\nd waves beat directly ^u ! membran\s w9d[s ( ! inn] e>1 ^! c\ld n be made to vibrate1 z !re is liquid beh9d !m1 & liquids are incompressible2 s1 9 ord] t ! movem5ts ( ! drum may be transmitt$ to ! liquids ( ! inn] e>1 !y are c>ri$ across ! middle e> by a *a9 ( small bones1 by :i* _! ext5t is curtail$1 b _! =ce increas$1 & br\ght to be> ^u "o only ( ! two op5+s4 ,! consequ5ce ( ?is is t ! membrane clos+ x is able to vibrate & pass on ! vibrations to ! liquid )91 s9ce :5 x is pu%$ 91 ! membrane cov]+ ! o!r hole is pu%$ out4 ,illu/ration3 ,,diagram #ei4--,,! ,,semicircul> ,,canals4 ,exactly h[ ! diff]5t p>ts ( ! membran\s labyr9? contribute to our p]ception ( s\nd we d n q "k4 ,x appe>s z ?\gh ! diff]5ce ( pressure 9 saccule & utricle orig9ally convey$ to ! bra9 a s5sation ( noise )\t any idea ( quality1 :ile ! co*lea 0 develop$ lat] to analyze s\nds & give in=mation z to pit* & tone4 ,:e!r ! re/ ( ! labyr9? has any long] a "p to play 9 ! p]ception ( s\nd1 we _c say ) c]ta9ty2 b x seems pretty c]ta9 t ! co*lea is ! organ = receiv+ musical impressions4 ,"h1 aga91 ?\gh1 we are at a loss1 = we d n "k ) c]ta9ty h[ ! co*lea acts4 ,9 %ape x is a long tube1 & 9 ! head is coil$ spirally--l a snail's %ell to look at4 ,along its :ole l5g? is a ridge ( cells ) %ort hairs project+ f _! inn] surface into ! liquid x conta9s2 & to ! cells along ?is ridge a bran* ( ! auditory n]ve is di/ribut$4 ,b z to :e!r "o ( ! cells along ?is keybo>d responds to ea* ( ! notes we c di/+ui%1 or :e!r !y are affect$ z a :ole1 physiologi/s are n yet agre$4 ,at lea/ "o o!r important duty ! e> p]=ms2 x tells u 9 :at position we are1 & h[ our :ole head moves or is mov$4 ,on ! top ( ! saccule1 9 ,diagram #eg1 ,fig4 #d1 !re are %[n ?ree little loops :i* are call$ ! semicircul> canals4 ,!y are %[n aga9 m cle>ly by !mselves 9 ,diagram #ei4 ,fig4 #a %[s _! position ) reg>d to ea* o!r4 ,x w be se5 t two ( !m are v]tical1 ) _! loops =m+ a "r angle ) "o ano!r1 & t ! o!r is horizontal--9 fact1 t !y lie 9 ! ?ree planes ( space4 ,fig4 #b %[s ! /ructure ( "o ( !m2 x has a swell+ at "o end 7a71 & a knob project+ into x :]e ! n]ve jo9s x 7b74 ,9 ,fig4 #c is %[n a section ?r\gh ?is knob1 :i* gives ! key to ! use ( ^! /ructures4 ,a little head ( cells projects f ! wall ( ! canal into its lum51 & f ^! cells hairs bri/le out into a dome-l cov]+ ( jelly1 weight$1 to prev5t its mov+ too easily1 ) small p>ticles ( lime4 ,n[1 if y take up a r\nd vessel full ( liquid--say a b[l ( gold-fi%--& give x a twi/ r\nd1 y w notice t1 ?\gh ! b[l turns1 ! wat] inside does n2 ! fi% rema9 9 _! old position4 ,if !re 7 a rod project+ f ! side ( ! b[l1 x w\ld1 ( c\rse1 move ) x1 & if a fi% came 9 its way w\ld /rike aga9/ x4 ,?is is ! pr9ciple ( ! semicircul> canal4 ,= if we turn our head1 ! tube ( ! canal turns1 pass+ ov] ! liquid 9 x1 :i* ( c\rse does n move1 ?\gh x appe>s to fl[ 9 ! opposite direction4 ,! consequ5ce is t ! hairs on ! side ( ! knob 9 ! direction 9 :i* ! head is be+ mov$ are press$ ^u by ! dome ( jelly1 :i*1 z x floats 9 ! liquid1 t5ds to rema9 :]e x is4 ,! n]ves1 /imulat$ 9 ?is way1 in=m ! animal g5]ally ( ! movem5t4 ,^! little organs are v important to u1 ?\gh we h our eyes to correct our ideas ( position1 & !y are /ill m s to ! fi%1 :i* d>t & turn 9 ! wide expanse ( ! ocean1 & ! birds & bats1 :i* :eel ab\t 9 ! air4 ,!re are1 h[ev]1 "s occasions :5 we d n feel incl9$ to bless !m2 =1 inasmu* z !y fai?fully report e roll & plunge ( a %ip to a p]son on bo>d1 x is !y :i* are ma9ly responsible = sea-sickness4 99 99 99 99 99 ,& n[ t we h se5 h[ ! body lies ) reg>d to ! ext]nal _w2 h[ x is effici5tly protect$ f its surr\nd+s2 h[ x is plac$ 9 communication ) !m2 & h briefly exam9$ ! organs by :i* x makes its *emical & physical inve/igations1 looks out into space1 & is kept aw>e ( :at is go+ on !re91 we may return to ! means :]eby x responds z a :ole to ! /imuli ?us report$--! c5tral n]v\s sy/em--& try to le>n h[ ! "r response is br\ght ab\t4 ,,iv4 ,!re is b "o ?+ m to describe 9 ! me*anism ( ! body--! connect+ l9k betwe5 ! la/ two sections4 ,9 ! la/ we saw h[ ! body receives /imuli f ! ext]nal _w2 9 ! "o be=e1 t :5 ^! /imuli rea* ! c5tral n]v\s canal x 9 turn /imulates ! organs to p]=m su* movem5ts z circum/ances require4 ,:at1 !re=e1 rema9s to be describ$ is ! work+ ( t canal by :i* ^! necess>y movem5ts are ord]$ & controll$4 ,n[1 9 speak+ ( reflex action a few pages back1 we said t ! n]ves :i* br+ 9 /imuli f ! p]iph]y di/ribute !m ab\t ! neural canal to ^? cells ^: activity1 by s5d+ out fre% /imuli to ! muscles1 produces ! requisite movem5ts4 ,^! motor cells1 h[ev]1 are n scatt]$ ab\t ! sp9al cord anyh[4 ,!y are collect$ into clu/]s1 or nuclei1 z !y are sometimes call$1 & ea* clu/] has special duties--i4e41 a special organ to control4 ,?us1 we say t !re are 9 ! c5tral n]v\s sy/em c5tres--a n]v\s c5tre to control ! leg2 ano!r to "w ! diaphragm2 ano!r = ! muscles ( ! ribs2 m = ! arm1 h&1 etc4 ,& ^! c5tres are 9 communication ) "o ano!r1 s t !y may n pull diff]5t ways4 ,9 ! fir/ example ( reflex action giv5 9 ,section ,,ii4 ( ?is essay1 ! s5sation ( a p9-prick 0 fir/ convey$ to ! c5tres controll+ ! limb injur$1 by ^: activity x 0 drawn away f ! dang]4 ,b ! n]ve :i* gave ! w>n+ :i* produc$ ?is elem5t>y movem5t di/ribut$ ! impression t some?+ 0 wrong to ! high] c5tres1 s t ! :ole body 0 involv$ 9 protect+1 doctor+1 & av5g+ ! outrag$ memb]2 f :i* x w\ld appe> t ! l[] c5tres are "u control ( high] ones4 ,& ?is is ! case4 ,if we may be all[$ ! metaphor1 !re are capta9s ( t5s1 :o are "u ! direction ( capta9s ( fifties1 & ! capta9s ( fifties receive _! ord]s f capta9s ( hundr$s4 ,! n]ve canal1 ! mann] ( ^: =mation z a simple tube is %[n 9 ,diagrams #e & #db1 has !re=e diff]5t functions 9 diff]5t p>ts1 & ?is to su* an ext5t t consid]able diff]5tiation 9 bulk & /ructure is produc$4 ,! neural canal may be r\ghly divid$ into two p>ts--a comp>atively simple tube1 runn+ ! great] "p ( ! animal's l5g?1 conta9+ _m c5tres f :i* n]ves run to ! organs !y control2 & a complicat$ bulb\s enl>gem5t at "o end1 ) ?ick5$ walls1 9 :i* are ! c5tres controll+ ^? 9 ! cord1 & !reby manag+ n s mu* organs z ! :ole animal4 ,! =m] is call$ ! sp9al cord1 ! latt] ! bra94 ,?is division1 accu/om$ z we all are to take x = grant$1 (f]s pl5ty ( food = reflection4 ,:y %\ld an animal h su* a bra9 plac$ 9 its head8 ,:y1 inde$1 %\ld x h a head1 reg>d+ t memb] z a gr\p compos$ ( eyes1 nose1 m\?1 e>s & bra98 ,! m\? gives u ! key to ! riddle2 ! m\? is ! ess5tial organ1 & all ! re/ are its accessories4 ,9 ! fir/ essay we saw t ! basis ( life 0 *emical1 & 9 ! second t ! mat]ials necess>y = ! *emical action1 or food1 mu/1 9 ! high] animals1 be tak5 into ! dige/ive tube ?r\gh ! op5+ :i* we call ! m\?4 ,!re=e1 z x is highly important t only ! mo/ b5eficial sub/ances %all be receiv$ into x1 & t all :i* are actively injuri\s %all be exclud$1 x is pla9 t ! organs ( *emical p]ception mu/ be plac$ 9 its neighb\rhood--! organs ( smell to enable ! m\? to f9d its food1 & ! organs ( ta/e to aid 9 select+ x4 ,z1 moreov]1 our humble ance/ors1 ! fi%es1 move lit]ally m\? =emo/1 x is n surpris+ to f9d ! organs ( space p]ception1 ! eyes1 also situat$ 9 its neighb\rhood1 especially :5 "o consid]s t _! food is (t5 ( a lively "*1 & requires precision ( movem5t to secure x4 ,! inevitable consequ5ce ( ?us gr\p+ ! m important organs ( p]ception "u ! =e-end ( ! neural canal is t x gr[s & develops m highly "h ?an else:]e along its l5g?1 & soon is 9 a position to dictate to ! re/ ( ! body4 ,ano!r reason :y x mu/ develop is t x mu/ conta9 c5tres = turn+ its impressions to practical acc\nt1 n only by produc+ complicat$ movem5ts 9 ! jaws1 eyes & gills1 b also by rul+ ! c5tres 9 ! cord1 & in/ruct+ ! body to c>ry ! m\? :i!r x ne$s to g4 ,illu/ration3 ,,diagram #fj4--,,%[+ ,,prim>y ,,division ,,( ,,n]v\s ,,tube4 ,9 ! prec$+ diagram 7#fj7 ! orig9 ( ! bra9 is %[n z a dilatation ( ! end ( ! neural canal into a bulb ) ?ick5$ walls1 :i* has already become con/rict$ 9 places1 s t x is subdivid$ into ?ree4 ,! next diagram 7#fa7 is int5d$ to give1 9 no matt] h[ crude & s*ematic a way1 "s idea ( ! l9es on :i* ! developm5t cont9ues4 ,we d n %[ all1 or ev5 half1 ! /ructures :i* g to make up ! bra94 ,to d s w\ld be out ( place 9 a book l ?is4 ,fur!r1 we %all endeav\r z f> z possible to speak ( ! bra9 9 g5]al t]ms1 avoid+ ! five-syllable ba/>d ,grco-,lat9 names ) :i* ! e>ly anatomi/s h end[$ almo/ e squ>e in* ( its sub/ance1 & conf9e ourselves to summ+ up its functions z briefly z c be done ) ju/ice4 ,illu/ration3 ,,diagram #fa4--;,,giv+ ,a ,,r\gh ,,idea ,,( ,,h[ ,,! ,,bra9 ,,is ,,develop$4 ,9 pursuance ( ?is me?od1 att5tion mu/ be drawn to ! fact t only ! =emo/ ( ! ?ree orig9al bulbs 7m>k$ ,a 9 ! diagram7 & ! h9d]mo/ 7,c7 cont9ue to gr[4 ,! middle "o 7,b7 rema9s comp>atively simple4 ,f ! =emo/ lobe buds gr[ out to =m ! eyes 9 ! mann] :i* we h already describ$1 & o!r buds pu% =w>ds to meet ! n]ves f ! nose4 ,! latt] h1 ev5 9 ! e>ly /ages %[n 9 ,diagram #fa1 rea*$ an extraord9>y size2 & :5 we come to trace !m fur!r1 we %all f9d t !y become v complex1 & acquire rem>kable & unexpect$ p[]s1 consid]+ _! humble orig94 ,/range *anges also take place 9 ! h9d]mo/ bulb4 ,x splits along ! top1 s t ! cavity x conta9s is op5 l a sauc]1 ?\gh bridg$ ov] by a ?ree-lob$ body call$ ! c]ebellum4 ,foll[+ ! sp9al cord up into ! bra91 we are consci\s ( no sudd5 l9e ( dem>cation sep>at+ ! "o f ! o!r1 only ( an increas+ size & complexity4 ,! l[] p>ts ( ! bra9 s5d out & receive n]ves mu* z ! cord does2 ?ree pairs g to ! muscles :i* turn ! eyes2 o!r pairs br+ 9 s5sations f ! face & ?roat2 o!rs control ! muscles ( ! face1 tongue & ?roat4 ,b ! bra9 diff]s f ! cord 9 be+ directly connect$ by n]ves1 n only ) adjac5t p>ts1 b also ) ! di/ant & m important organs 9 ! int]ior ( ! body--he>t1 lungs1 etc42 9 conta9+ gr\ps ( cells :i* h /imuli s5t on to !m f all ov] ! body vi ! cord2 & 9 possess+ c5tres :i* control ^? l[] d[n 9 ! n]v\s sy/em4 ,x !re=e n only receives & balances /imuli f all ov] ! body1 b1 by gov]n+ ! c5tres :i* preside ov] ! bodily movem5ts1 is able to wield & direct ! body z a :ole4 ,! h9d] divisions ( ! bra91 :i* we %all consid] fir/1 h no connection ) consci\sness or volition4 ,!y only produce reflex movem5ts1 :i*1 h[ev]1 ow+ to ! weal? ( mat]ial !y h to "w ^u1 are wond]fully complex & f>-rea*+4 ,let u take a few examples4 ,9 ! h9d]mo/ division ( ! bra9 7,c 9 ! diagrams7 !re is ! c5tre :i* presides ov] ! oxyg5 supply1 ! importance ( :i* we saw 9 ! essay on vital *emi/ry4 ,?is c5tre p]ceives :5 ! lungs h be5 fill$ ) a gas1 & causes !m to be empti$2 x p]ceives :5 !y are empty1 & aga9 does n all[ !m to rema9 too long 9 t /ate1 be=e ord]+ an inspiration2 x notes ! quality ( ! air :i* is pass+ ?r\gh ! nose1 & x notes ! quality ( ! blood :i* ba!s its own cells4 ,! condition ( ! blood1 inde$1 is closely wat*$4 ,an excessive quantity ( c>bonic acid gas1 pov]ty ( oxyg51 ev5 temp]ature1 all produce ?r\gh x an effect ^u ! rhy?m ( ! brea?+4 ,close by ! respiratory c5tre is ! c5tre :i* controls ! circulation4 ,b en\gh has be5 said 9 ! section on reflex action1 :]e9 ! process ( fa9t+ 0 describ$1 to give an idea ( ! "p x plays 9 ! body2 s x ne$ n deta9 u "h4 ,we _c1 h[ev]1 pass ov] its neighb\r1 ! c5tre ( temp]ature1 s briefly4 ,its me?ods n only af=d "o ( ! mo/ /rik+ & int]e/+ examples ( h>moni\s regulations by reflex action1 b ! subject ( temp]ature itself is s important t we mu/ describe 9 "s detail h[ t ( ! body is kept level4 ,z we said :5 discuss+ protoplasm g5]ally1 life--t is1 ! *ange always go+ on 9 ! protoplasmic sub/ance--is influ5c$ by temp]ature3 ! s+le cell becomes less active at a l[ temp]ature1 & dies at a high "o2 s obvi\sly !re is a temp]ature at :i* its functions are mo/ easily c>ri$ on4 ,inside ! body ! cells are all kept at ! temp]ature be/ = !m by ! circulation ( ! blood2 b ! absolute temp]ature ( ! :ole body dep5ds ^u ! heat :i* is g5]at$ )9 x by *emical action1 & ! heat :i* x loses to1 or receives f1 its surr\nd+s4 ,"u normal conditions ?is temp]ature 9 man is #ihd ,f41 :5 ! production ( heat f its own metabolism is balanc$ by ! loss ( heat by radiation4 ,if1 h[ev]1 ! atmosph]e be v hot1 less heat is develop$ 9 ! body1 ! g5]al metabolism be+ sl[]2 & m heat is lo/1 s9ce by reflex action ! sk9 is ba!d 9 sweat & cool$ by its evaporation1 & ! small bloodvessels "u ! sk9 are dilat$1 s t m blood be+ br\ght to ! surface1 its *ance ( be+ cool$ by radiation is !reby increas$4 ,if1 on ! o!r h&1 ! atmosph]e is cool1 ! loss at ! surface is m9imiz$ by con/riction ( ! cutane\s bloodvessels1 & a *eck+ ( ! p]spiration & consequ5t evaporation2 :ile int]nally m heat is g5]at$ by increas$ metabolism4 ,! cells :i* are ma9ly responsible = ! production ( heat are ^? ( ! muscles2 & :5 mu* heat is requir$ !y increase 9 activity1 n only 9 _! g5]al tone1 b ev5 by a visible movem5t1 :i* we describe z %iv]+4 ,s1 )9 reasonable limits1 :atev] ! temp]ature ( its surr\nd+s may be1 t ( ! body rema9s ! same1 & ?\gh we may raise or l[] our temp]ature by ly+ 9 a hot or cold ba?1 reflex adju/m5t ( ! sweat gl&s1 bloodvessels & muscles br+s x quickly back to normal :5 we em]ge4 ,) a pass+ m5tion ( ! c]ebellum1 ! ?ree-lob$ organ %[n 9 ,diagram #fa1 & se5 aga9 9 a m advanc$ /age 9 ,diagram #fc1 we may dismiss ! two h9d] divisions ( ! bra94 ,! c]ebellum lies on ! upw>d pa? ( fibres f ! cord to ! high] c5tres 9 ! =e-bra94 ,x is a some:at complicat$ organ1 & its functions are n yet fully kn[n4 ,! old] physiologi/s took a v extreme view ( its importance1 assign+ to x1 among o!r romantic duties1 t ( provid+ a habitation = ! s\l4 ,?is op9ion on ! /r5g? ( lat] rese>* we c h>dly endorse4 ,! c]ebellum really seems ma9ly conc]n$ 9 co-ord9at+ ! action ( ! muscles1 especially 9 ma9ta9+ equilibrium 9 /&+ & walk+4 ,our k ( ! :ole bra9 is v f> f complete4 ,we %\ld l to "k ! peculi> function ( ea* little gr\p ( cells t c be made out "u ! microscope1 & ! pa?s ( all ! fibres connect+ ! diff]5t p>ts ( ! n]v\s sy/em4 ,z x is1 we h to wait ) ! be/ pati5ce we c :ile !y are be+ inve/igat$1 & hope4 ,9 few dep>tm5ts1 h[ev]1 h ! lab\rs ( ! physiologi/ prov$ m fruitful & int]e/+ ?an 9 ! /udy ( ! =e-bra9 7,a 9 ! diagrams74 ,9 ! simpl] =m1 z %[n 9 ,diagram #fa1 ,a1 & ,diagram #fb1 ,fig4 #a1 ,a1 ! =e-bra9 is rem>kable 9 t x ?r[s out buds = ! two mo/ important s5se organs--^? ( sight & smell4 ,s important are ^! s5ses1 especially 9 our humble ance/ors1 z we h already po9t$ out1 t x is n surpris+ to f9d ! impressions ( ! o!r s5ses br\ght on up f ! h9d] p>ts ( ! bra9 to be comp>$ ) !m4 ,! =e-bra9 is1 9 fact1 a sort ( t]m9us :i!r ! :ole ( ! aff]5t or incom+ /imuli are br\ght1 & :5ce1 s9ce in=mation is only receiv$ 9 ord] to be act$ ^u1 ! supreme ord]s to ! body issue4 ,9 ! =e-bra9 !re are c5tres = specially gov]n+ all ! motor organs2 b by a /range arrangem5t ! ma9 root ( ! bra9 is ov]:elm$ by its own (f%oot1 ! hemisph]e1 or lobe :i* gives rise to ! olfactory bud4 ,9 fact1 s great is ! importance ( ! s5se ( smell to an animal ^: "o object 9 life is to f9d food1 t1 in/ead ( ! hemisph]e be+ subord9ate to its p>5t1 x seems to take ov] mo/ ( ! latt]'s bus9ess1 receiv+ a report ( ! s5sations collect$ by x1 & s5d+ out ord]s ^u its own initiative4 ,yet1 unimpos+ ?\gh ! hi/ory ( ?is division ( ! bra9 may be1 x ultimately becomes ! seat ( consci\sness1 :]eby ! m5tal processes are c>ri$ on1 & :5ce all volunt>y movem5ts spr+4 ,illu/ration3 ,,diagram #fb4--,,%[+ ,,h[ ,,! ,,c]ebral ,,hemisph]es ,,are ,,develop$ ,,f ,a1 ,,! ,,=emo/ ,,bulb ,,( ,,! ,,bra94 ,( c\rse1 9 ord] to d ?is1 ! hemisph]es h to gr[ consid]ably1 & ?us we f9d !m envelop+ ! re/ ( ! =e-bra9 & swamp+ x 9 /ructure z well z 9 function4 ,diagram #fb indicates h[ ?is is done1 :ile ,diagram #fc %[s r\ghly ! proportion & position ! diff]5t p>ts ( ! bra9 ultimately atta94 ,f9ally1 ,diagram #fd1 :i* is r m reali/ic1 b /ill mu* simplifi$1 pres5ts a view ( ! organ 9 ! head4 ,! size ( ! c]ebral hemisph]es1 comp>$ ) ! re/ ( ! bra91 is especially rem>kable4 ,s1 too1 is _! endeav\r to increase _! surface /ill m by ?r[+ x into deep folds4 7,see ,diagram #fd47 ,^! two features v>y ) ! position ( ! animal 9 ! scale ( developm5t2 9 man1 :o /&s highe/ 9 intellig5ce & dext]ity1 ! hemisph]es are v l>ge inde$ comp>$ ) ! o!r organs1 & seam$ all ov] ) a maze ( w9d+ furr[s4 ,ano!r rem>kable feature is ! extreme degree to :i* specialization is c>ri$ out4 ,diff]5t p>ts ( ! body are repres5t$1 ea* by a small area ( ! cortex1 or surface lay]1 & we "k at :at spot on ! cortex su* s5sations z sight & he>+ are p]ceiv$1 & f exactly :at little pat* ! impulse to move ea* limb emanates4 ,9 ! accompany+ diagrams 7#fe & #ff7 ^! areas are mapp$ out1 _! locality be+ fix$ by ! pr9cipal folds :i* act z l&m>ks on ! surface ( ! hemisph]e4 ,illu/ration3 ,,diagram #fc4--,,relation ,,( ,,diff]5t ,,p>ts ,,( ,,! ,,bra94 ,!re is ano!r important fact :i* we mu/ n omit to m5tion 9 speak+ ( ?is localization3 ea* hemisph]e presides ov] ! opposite side ( ! body4 ,e>ly 9 developm5t ! n]ve fibres f ! eye cross ov] to ! opposite side ( ! bra91 & ! aff]5t fibres f ! l[] p>ts ( ! body h accord+ly to foll[ suit4 ,!n1 z ! eff]5t fibres--i4e41 ^? :i* set ! muscles 9 motion--h to br+ ab\t ! movem5ts 9 response to in=mation receiv$1 !y mu/ also cross to get back to ! side f :i* x came4 ,s1 if a tum\r gr[s inside ! head on ! "r side1 x is ! left eye :i* becomes sightless1 or ! left h& :i* gr[s numb & p[]less1 accord+ to ! "p ( ! cortex :i* is press$ ^u4 ,p]haps ! mo/ int]e/+ "p ( ! :ole body is t little b& ( ! cortex runn+ upw>ds f beh9d ! temple to ! cr[n ( ! head1 9 :i* 7cf4 ,diagrams #fd1 #fe & #ff7 ! motor areas ( ! limbs1 & ! p]ception ( ^? s5sations :i* we h gr\p$ toge!r & call$ #8t\*1' are situat$4 ,! m9ute /ructure ( ?is region is r\ghly %[n 9 section 9 ,diagram #fg1 z x has be5 made out ) ! microscope2 b only a few ( ! n]ve cells are %[n1 ! connective tissue ( feltwork 9 :i* !y are susp5d$1 & ! bloodvessels by :i* !y are n\ri%$1 be+ left out4 ,all ! /ructures repres5t$ are ( c\rse v1 v small2 ! l>ge black pat*es :i* repres5t cells w\ld really be invisible1 & ! :ole field ( ! diagram only a m]e speck1 to ! nak$ eye4 ,illu/ration3 ,,diagram #fd4--,,position ,,( ,,! ,,bra9 ,,9 ,,! ,,head4 ,a repres5ts ! n]ve by :i* impulses are br\ght 94 ,x runs /raight up to ! surface ( ! cortex1 & !re its bran*es end1 int]lac$ ) ^? ( a _m-bran*$ di/ribut+ cell 7,b74 ,! two cells 7,c & ,d7 %ap$ l pyramids1 :i* s5d up bran*$ processes f _! apexes1 receive an impulse f ! di/ribut+ cell1 & transmit x along ! fibre :i* runs d[nw>ds f ! middle ( _! base4 ,:]e ! fibre f ! small] "o goes to we are n sure--probably to ano!r "p ( ! bra9 to insure h>moni\s work+--b ! l>ge pyramidal cell s5ds its fibre "r away ?r\gh ! l[] p>ts ( ! bra91 pass+ ! cell-/ations !y conta91 on into ! sp9al cord1 till x rea*es ! c5tre !re1 :i* imm$iately works "s p>ticul> limb4 ,illu/ration3 ,,diagram #fe4--,,map ,,( ,,! ,,c]ebral ,,hemisph]e1 ,,%[+ ,,! ,,areas ,,9 ,,:i* ,,v>i\s ,,functions ,,are ,,localiz$4 ,suppos+ we an/hetiz$ somebody1 ?r[+ him into deep unconsci\sness1 & !n op5$ 8 skull1 lay+ b>e ! bra9 z is done 9 ,diagram #fd1 only n q 9 su* a :olesale mann]4 ,if we !n /imulat$ ! "p ( ! bra9 we are n[ consid]+ at diff]5t places ) electric ne$les1 us+ a weak induction curr5t1 we %\ld see him mov+ diff]5t memb]s accord+ to ! diff]5t regions t\*$--n[ an arm1 n[ a leg1 n[ ! :ole head4 ,if we 7 to place ! electrodes 9 ! c5tre = ! h&1 & !n gradually increase ! /r5g? ( ! curr5t1 ! activity ( ! h& c5tre w\ld ?r[ o!r c5tres into activity4 ,! arm w\ld move next1 rais+ ! h& t[>ds ! face4 ,!n ! eyes w\ld turn1 & ! :ole head to meet ! h&4 ,la/ly ! m\? w\ld op54 ,! movem5ts are ^? ( putt+ some?+ into ! m\?--! rul+ passion /rong 9 unconsci\sness4 ,illu/ration3 ,,diagram #ff4--,,map ,,( ,,! ,,c]ebral ,,hemisph]e1 ,,%[+ ,,! ,,areas ,,9 ,,:i* ,,v>i\s ,,functions ,,are ,,localiz$4 ,su* exp]im5ts 71 ( c\rse1 fir/ made ^u animals1 b !y h be5 fully v]ifi$ on ! human subject4 ,! /ory ( h[ ?is 0 done is n1 h[ev]1 a romance ) a m>tyr or a crim9al = ! c5tral figure4 ,! corpus vile 0 n provid$ by a volunte]1 or kidnapp$ & b\nd 9 a d>k cell>1 b treat$ z a pati5t 9 ! airy w>ds ( a hospital4 ,) increas+ k ( ! bra91 x 0 f\nd t epilepsy 0 cortical 9 orig94 ,a little piece ( ! cortex becomes diseas$ & hyp]excitable4 ,! suff]] sudd5ly becomes acutely consci\s ( "o ( 8 memb]s--a h& or a foot1 say--n because !re is any?+ ! matt] ) x1 b because ! correspond+ area 9 ! bra9 is morbidly active1 & he ref]s ! s5sation to ! "p f :i* x receives its n]ves4 ,! next mom5t ! limb beg9s to twit*1 & ! excitem5t spread+1 z 9 ! exp]im5t we describ$ above1 to o!r c5tres :i* are n diseas$1 !y1 too1 become morbidly active1 & ! :ole body is ?r[n into convulsions4 ,?is is a disease :i* mu/ be *eck$ z soon z possible4 ,! surgeon accord+ly lays b>e ! "p ( ! bra9 affect$1 kn[+ n[ :]e to look2 f9ds ! exact spot :i* is diseas$ by reproduc+ ! fir/ twit*+s ( a fit by electric /imulation1 & removes ! s\rce ( ! tr\ble4 ,illu/ration3 ,,diagram #fg4--,,%[+ ,,! ,,sy/em ,,( ,,n]ve ,,cells ,,9 ,,! ,,cortex4 ,a1 ,aff]5t fibre2 ,b1 di/ribut+ cell2 ,c1 small pyramidal cell2 ,d1 l>ge pyramidal cell4 ,return+ to g5]al consid]ations1 an important po9t is ! way 9 :i* ! diff]5t c5tres are connect$ by fibres1 :i* put !m into relation4 ,! bra9 may consi/ ( _m c5tres1 j z ! body consi/s ( _m organs1 b bo? body & bra9 mu/ live z a :ole4 ,if ! he>t & lungs get out ( h>mony !re is tr\ble1 & if ! bridge :i* connects he>+ ) motion 9 ! bra9 breaks d[n1 z occasionally happ5s = a "t 9 an ov]work$ man1 he is m5tally at a disc\nt4 ,he c he> & und]/&1 b he _c write or talk s5se3 he is sane1 b q helpless1 & g5]ally v fright5$4 ,/ill m important are ! int]m$iate /ations & sid+s on ^! l9es ( communication1 = x is "h t ! mo/ exhau/ive weigh+ & comp>+ ( incom+ /imuli is c>ri$ on--! f9al balanc+ be=e a volunt>y action2 9 a ^w1 ?\ght4 ,^! c\rts ( inquiry are call$ association c5tres4 ,x us$ to be believ$ t !y 7 all 9 ! =e-"p ( ! bra91 "u ! =ehead2 b ?is is evid5tly n ! case4 ,sev]al m5 9 w> or by accid5t h _h ! frontal lobes ( _! bra9 damag$ beyond repair2 & :5 !y h be5 dis*>g$ f hospital1 :]e1 ?anks to ! advance made by surg]y s9ce an/hetics & antiseptics 7 discov]$1 !y h be5 successfully treat$1 !y h gone back to _! "w seem+ly 9 no way diff]5t f m5 ^: bra9s 7 :ole4 ,9 "s cases !y h ev5 be5 report$ z hav+ become quick] & %>p] ?an be=e1 probably ow+ to !re be+ few] association c5tres1 & ?\ght be+ accel]at$ by simpl] ma*9]y3 facts are !nce=w>d %ak5 ?r\gh a l>g]-me%$ sieve4 ,a few g5]al consid]ations1 & we h done4 ,!re is no c5tre = memory 9 ! bra94 ,! facts :i* we rememb] are n /or$ z 9 a box1 nor c "o imag9e h[ !y c\ld be1 consid]+ t ! physical basis ( an idea is molecul> *ange4 ,! :ole n]v\s sy/em is probably conc]n$ 9 memory1 a p>ticul> *ange1 :i* has mom5t>ily occurr$ 9 its tissues1 be+ m likely to occur aga9 "u c]ta9 circum/ances ?an a fre% "o1 & c]ta9 tracks becom+ well beat5 & m p]meable ?an o!rs4 ,pleasure & pa9 are o!r g5]al ph5om5a3 !y are n to be localiz$ 9 ! bra9 l vision or he>+4 ,pleasure is ! consci\sness t ! :ole body is "u fav\rable conditions2 & pa91 ! k t ! protoplasm ( c]ta9 cells ( ! body is be+ act$ ^u by injuri\s ag5ts1 *emical or physical4 ,!re seems to be good evid5ce t sep>ate n]ves convey impressions ( injury1 di/9ct f ^? ( t\* & temp]ature2 b x is ! revolt ( ! :ole body aga9/ conditions affect+ a "p :i* con/itutes pa94 ,amid/ ! maze ( p]plexities :i* lies betwe5 physiology & psy*ology1 !re is1 h[ev]1 "o fact :i* /&s out cle> & bold3 ! bra9 c create no?+4 ,we h se5 h[ matt] is tak5 into ! body & matt] is ca/ (f f ! body4 ,we h se5 h[ en]gy is releas$ 9 ! body f *emical comp\nds1 & made use ( by ! body4 ,s n[1 aft] a mom5t's ?\ght1 x mu/ be pla9 t e /imulus :i* goes to ! bra9 mu/ h its effect !re1 & t a man's ?\ghts & conduct are entirely dep5d5t on :at has1 at "s "t or o!r1 come 9 f ! ext]nal _w4 ,! association c5tres c evolve wond]ful ?\ghts1 b !y are /ructurally d]iv$ f ! gross] s5se organs1 & mu/ get all ! mat]ial !y "w ^u f !m4 ,! n]v\s sy/em puts ! body into relation ) ! ext]nal _w z a :ole1 b = conv5i5ce x is subdivid$ into ! aff]5t sy/em1 by :i* impressions come 91 & ! eff]5t sy/em1 by :i* ! muscles are set 9 motion4 ,( ! two halves1 ! aff]5t sy/em has a j "r to priority1 = ! eff]5t sy/em is m]ely its consequ5ce4 ,sights1 s\nds1 smells1 etc41 rea* ! bra9 by aff]5t pa?s f ! ext]nal _w1 & are !re m\ld$ into ?\ghts4 ,_! effects we see 9 poetry1 ar*itecture1 sculpture1 or laundry "w1 accord+ to ! me?od ( ! bra9 9 treat+ ! raw mat]ial x receives1 & ( a quality correspond+ to ! f95ess ) :i* ! bra9 exam9es !m1 & c control ! motor organs ( ! body4 ,:atev] goes 9 at ! aff]5t door1 & "s p's s5sory app>atus is mu* m easily affect$ ?an o!rs1 produces its effect )94 ,sometimes ! en]gy is exp5d$ 9 ?\ght1 sometimes 9 action2 sometimes x trickles away z laught]4 ,b all ^! ph5om5a h a mat]ial basis3 matt] produc+ *anges 9 matt]4 #8,^? delicate tissues :]e9 ! s\l transacts its e>?ly bus9ess1' z ,/ev5son s picturesquely describes ! bra91 /ick to _! e>?ly bus9ess4 ,!re is no a/ral dep>tm5t op5$ yet4 ,a man may evolve a great idea f ! data he receives1 b he mu/ give x a mat]ial coeffici5t if he does n wi% x to be lo/ to 8 e>?-b\nd bro!rs4 ,he may write x 9 a book1 or he may sculpture x 9 m>ble2 b ! mo/ conv5i5t means ( communicat+ ) 8 fell[s is by s\nd1 :i* he c comm& by expell+ ! air 9 8 lungs ov] vibrat+ cords 9 8 ?roat4 ,^! cords are adju/$ at ! position & t5sion to give a desir$ note2 & ! cavities ( ! *e/1 ?roat & m\? act+ z resonators1 a noise is produc$1 :i* is %ap$ by ! tongue1 lips & tee? into words4 ,by means ( language ! human body is enabl$ to co-op]ate ) o!rs ( its k9d = ! developm5t ( ! res\rces ( ! e>?1 ! %ap+ ( society1 & ! =m+ ( individual "*4 ,b "h physiology ends & o!r sci5ces beg94 ,,essay ,v4 ,,! ,,body4 ,i4 ,su*1 z f> z x c be compress$ into f\r %ort essays1 is ! nature ( protoplasm4 ,we h sket*$ out its p[]s2 describ$ h[ x exi/s only 9 ! =m ( a cell2 & %[n h[ cells1 by =m+ a community & %>+ ! "w1 simplify ! bus9ess ( liv+1 & secure great advantages = !mselves individually4 ,b n[ we h some?+ fre%--! body4 ,! body is an organic :ole1 l ! cell4 ,x is compos$ ( cells1 b ^! cells only develop "o ( _! _m p[]s to its utmo/ t !y may ju/ify _! exi/5ce 9 ! community2 !y d n acquire fre% prop]ties4 ,s really ! body is m]ely a mass ( protoplasm 9 :i*--?\gh 9 a great] quantity--! same *anges are go+ on t we f9d 9 a s+le cell4 ,yet h[ utt]ly diff]5t is ! body f ! cell6 :at a wide gulf yawns betwe5 a man & an amba6 ,! body has p[]s ( its own1 di/9ct f ^? ( protoplasm2 & ! protoplasm may /ill be alive :5 ! body x help$ to compose is dead4 ,a few ?\s& p\nds ( protoplasm c\ld n h built ,we/m9/] ,abbey1 b a few hundr$ m5 did2 = j z out ( protoplasm arises ! body1 s ! body gives rise to ! m9d1 a ?+ z mu* above x z x is above ! cell4 ,s f> we h tak5 ! cellul> units z our />t+-po9t 9 discuss+ life2 b a bird's-eye view ( physiology w\ld be incomplete :i* conta9$ no m5tion ( ! major tactics ( protoplasm--! life ( ! body4 ,we mu/ consid] ! ne$s ( a man z su*4 ,a man requires1 z we h describ$ be=e1 air & food4 ,! air mu/ conta9 ! prop] am\nt ( oxyg51 & ! food mu/ consi/ ( liquids & solids4 ,! important liquid is wat]4 ,m ?an half by weight ( ! :ole body is wat]1 & we are always los+ x3 ?r\gh ! sk91 ?r\gh ! lungs1 & ?r\gh ! kidneys4 ,p may dr9k alcohol ) wat]1 b n in/ead ( x4 ,inde$1 ! m alcohol !y take1 ! m wat] !y require1 = if !y take _! spirits 9 an undilut$ =m1 !y take wat] out ( ! body4 ,if y dip a piece ( wet clo? into alcohol = a m9ute1 x dries ) rem>kable rapidity1 because ! wat] has be5 absorb$ out ( x4 ,9 ! same way1 if y dr9k neat spirits1 !y pass into ! blood & /imulate ! n]v\s sy/em1 ultimately be+ excret$ by ! kidneys2 b on _! way ?r\gh ! tissues !y absorb a great deal ( wat]1 :i* mu/ be replac$4 ,milk is (t5 spok5 ( z ! ideal food1 & s x may be = v "y animals2 b x lacks "o important con/itu5t--iron4 ,a "y animal is born ) en\gh iron 9 its body to d )\t any 9 its food until x c take some?+ bett] ?an milk4 ,if x is wean$ late x becomes anmic4 ,an adult animal requires iron & also a c]ta9 am\nt ( solid food4 ,its alim5t>y canal is provid$ ) a good deal ( muscle2 & ?is muscle1 to be kept heal?y1 mu/ h some?+ to "w ^u--9 fact1 be ex]cis$4 ,a man's food %\ld conta9 a c]ta9 am\nt ( co>se mat]ial--cellulose1 = in/ance1 :i* =ms ! envelope ( vegetable cells4 ,& "h we see a di/9ctive feature ( ! body4 ,protoplasm c make no use ( cellulose1 !re is no dige/ive juice :i* w act ^u x2 b its pres5ce 9 ! alim5t>y canal 9 ! =m ( husk & small se$s /imulates ! walls by contact1 & produces p]i/altic movem5ts4 ,9 ,essay ,,ii41 :i* dealt ) ! *emi/ry ( ! body1 we said t if we 7 only to live ^u meat we %\ld tax our dige/ive app>atus sev]ely by hav+ to eat m proteid ?an we requir$ 9 ord] to get en\gh c>bon4 ,! conv]se1 h[ev]1 is equally true3 if we f$ only ^u vegetables1 we %\ld aga9 h to ov]-eat4 ,plants mo/ ( !m conta9 l>ge /ores ( c>bohydrate2 potatoes & rice are ri* 9 />*1 onions 9 sug>2 b an exclusively veget>ian diet w\ld necessitate our consum+ huge quantities1 z its proteid-supply is bad4 ,x is defective n only 9 am\nt--= sometimes1 z 9 beans1 ! proportion is fairly l>ge--b 9 be+ s indige/ible t a good deal ( x passes ?r\gh ! body unabsorb$4 ,bo? sci5ce & exp]i5ce tea* t we live mo/ economically ^u ! c>bohydrates ( vegetables & ! proteid ( animals1 & t our food is ! bett] = be+ cook$4 ,9 cook+1 p>asitic animals :i* are /rong en\gh to survive ! ordeal by acid 9 ! /oma* are kill$1 & ! food itself is made m accessible1 ! indige/ible cellulose envelopes ( ! vegetable cells be+ bur/ op51 & ! collag5 ( ! connective tissues conv]t$ into gelat94 ,no less important ?an ! quality ( our food is ! quantity2 & "h1 aga91 we get a good illu/ration ( ! necessity = reg>d+ ! body z a :ole4 ,a heal?y man's appetite is 8 be/ guide1 & if he foll[s x he _c g f> wrong4 ,p :o arrogate to !mselves a wisdom sup]ior to t ( ,nature little "k ! h>m !y d :5 !y =ce food d[n an unwill+ ?roat4 ,! cells ( ! alim5t>y canal dige/ & absorb :at is s5t to !m1 m9d+ _! own bus9ess1 :i* is n to criticise ! appetite4 #8,!irs n to "q :y2 ,!irs b to d & die4' ,s ! dige/ive & excretory sy/ems emb>k on h>d & pr(itless lab\r1 & ! :ole body suff]s4 ,pass+ on to ano!r subject1 we f9d t ! body eats t x may "w1 & works t x may eat4 ,?is cycle comes naturally en\gh to animals :i* h to g & f9d _! food1 b m5 ) a s$5t>y occupation h1 9 view ( ! artificial conditions "u :i* !y live1 to take con/itutional ex]cise4 ,!re are _m reasons :y ! num]\s & bulky muscles ) :i* ! body is end[$ mu/ be con/antly us$4 ,9 ! ?ird essay 9 ?is volume we saw t ! fl[ ( ! lymph & ! blood 9 ! ve9s is l>gely dep5d5t ^u ! movem5ts ( ! limbs4 ,muscul> ex]cise1 !re=e1 mu/ be tak5 to prev5t ! circulat+ /reams f gr[+ sluggi%4 ,obvi\sly1 _m evils mu/ arise if !y d s4 ,n only w\ld ! muscles be />v$ by ! sl[ness ) :i* !y receiv$ _! food1 b !y w\ld also be poison$ by ! sl[ness ) :i* ! products ( _! own metabolism 7 remov$4 ,! blood-/ream w\ld become ta9t$1 & ! bra91 :i* requires pure blood1 w\ld suff]4 ,9 o!r ways1 h[ev]1 ?an by _! action on ! vessels !mselves d ! muscles help ! circulation4 ,ex]cise has second>y effects ^u ! circulatory & respiratory c5tres 9 ! base ( ! bra91 & makes ! he>t beat m /rongly & ! diaphragm contract m =cibly4 ,! influ5ce ( ! latt] ^u ! circulation we h already describ$2 b its vigor\s action is requir$ n only to aid ! circulation ?r\gh ! liv] & visc]a1 b to inflate ! lungs to _! fulle/ ext5t4 ,9 ! brea?+ ( a man :o takes no ex]cise only a small "p ( ! air :i* ! lungs hold is pump$ out at ea* brea?1 ! great] "p rema9+ /agnant 9 *amb]s :i* are practically unus$4 ,?us1 n only is ! rev5ue ( oxyg5 dim9i%$1 b !re are num]\s little crannies 9 ! body fill$ ) /ill1 w>m air :i* are ideal nurs]ies = bact]ia4 ,! devil ( consumption does n all[ su* dwell+s to long rema9 swept & g>ni%$4 ,)\t ex]cise ! sweat gl&s ( ! sk9 w n act1 & its pores get clos$ up4 ,! muscul> coats ( ! alim5t>y canal1 too1 reflect 9 _! /ate ( heal? ! condition ( ! volunt>y muscles2 laz9ess is foll[$ by con/ipation1 = if ! volunt>y muscles ru/1 s d ! involunt>y4 ,! muscles1 moreov]1 mu/ be well develop$ & kept 9 a heal?y condition = _! own sake4 ,!y =m a l>ge "p ( ! :ole bulk1 & no heal?y man c h unheal?y muscles4 ,ignorant p sne]+ly say t !y h no ambition to lift weights or b5d pok]s2 b !y %\ld rememb] t !y are dep5d5t ^u _! muscles = _! bodily w>m?1 & also to save _! int]nal organs f be+ oppress$ by _! own weight4 ,! bones ( ! skeleton d n re/ "o ^u ano!r2 !y are jo9t$1 & kept slung 9 position by spr++ b&s ( muscle atta*$ to _! lev]s4 ,if ^! muscles are n prop]ly develop$1 !y tire "u ! /ra9 ( hold+ ! frame up1 & a disa/r\s re>rangem5t ( ! organs is made to save lab\r4 ,! *e/ is drawn 91 ! hips & knees ?ru/ =w>d1 & ! man /&s ) cramp$ *e/1 compress$ visc]a1 & 8 diaphragm "u dire con/ra9t4 ,! result ( ! r$i/ribution ( weight is t 8 bones t5d to re/ ^u "o ano!r l a column ( bricks1 & 8 :ole weight is ^u 8 heels4 ,su* an individual _c walk2 he /umps along1 j>r+ 8 :ole body at e /ep4 ,a pleasant contra/ is ! a?lete4 ,! a?lete is a man :o endeav\rs to develop ! lat5t p[]s ( 8 body to ! utmo/2 & 9 ! a*ievem5t ( ?is desirable object ! physiologi/ takes great int]e/4 ,physiology has revolutioniz$ our ideas ( tra9+1 z well z _m o!r ?+s1 dur+ ! la/ half-c5tury4 ,we n[ recognise two k9ds ( tra9+--! prep>ation :i* a heal?y man makes = an occasion on :i* unusual ex]tions w be expect$ ( him1 & ! sl[] & p]man5t /r5g!n+ ( ! :ole body1 n[ usually call$ physical culture4 ,! =m] is a comp>atively %ort process n[ t a?letes no long] ?9k x de rigueur to live 9 be/ial intemp]ance :5 !y h no conte/ 9 imm$iate prospect4 ,a little extra ex]cise1 to /imulate excretion & cle> away any wa/e products t may h accumulat$ 9 ! tissues2 a little extra proteid 9 ! diet1 s9ce !re is at fir/ a slight incl9ation to gr[?2 a good deal ( extra c>bohydrate1 s9ce ! muscles want extra fuel2 re/--& ! man is ready4 ,_m a?letes live cont9ually 9 tra9+1 & are ready at any mom5t to #8fight = _! lives4' ,! second k9d ( tra9+ is = ^? :o are weakly or ^? :o wi% to excel4 ,its object is n only to improve ! heal?1 b to increase ! absolute /r5g? & size ( ! body1 & its effects are p]man5t4 ,x necessitates c>eful diet & con/ant ex]cise = a long p]iod1 & proves equally b5eficial to bo? sexes4 ,?is book has be5 writt5 9 va9 if ! read] has n grasp$ by n[ t ! activity ( ! muscles implies ! activity ( all ! organs 9 ! body4 ,accord+ly1 ! :ole muscul> sy/em is by appropriate me?ods giv5 frequ5t ex]cise3 g5tle at fir/2 nev] exhau/+2 b con/antly increas+ z ! /r5g? gr[s4 ,! result is a g5]al developm5t ( ! organs ?r\gh\t ! body1 :i* w 9 "t "w a complete metamorphosis 9 ! individual's physique4 ,yet by /r5g? alone no a?lete c excel2 success dep5ds ^u skill4 ,he mu/ h ! /r5g? to "w )1 b he mu/ h ! k to apply x )\t wa/+ en]gy1 & ! ability to d ?is ) precision4 ,he mu/ practise well ! sport he int5ds to adopt--9 o!r words1 tra9 8 c5tral n]v\s sy/em4 ,"h1 aga91 we mu/ h>k back to ! ma9 idea--! unity ( ! body4 ,we h already dealt 9 ?is essay ) ! bodily ne$s 9 ! way ( food & ex]cise1 & we mu/ n[ consid] ! ne$s ( its n]v\s compon5ts4 ,! *ief ( ^! is education2 b education ( ! n]v\s sy/em means1 ( c\rse1 education ( ! :ole body4 ,!re are /ill p :o cl+ to ! old fallacy t ! m9d c be develop$ at ! exp5se ( ! body1 b a visit to a hospital or a lunatic asylum w af=d _m opportunities ( see+ h[ ,nature av5ges ill-treatm5t ( #8^? delicate tissues :]e9 ! s\l transacts its e>?ly bus9ess4' ,physical culture mu/ come be=e m5tal3 ,m5s sana 9 corpore sano--hackney$1 b true4 ,i d n1 ( c\rse1 say t a man mu/ develop equally bo? 8 body & m9d2 only1 t ! =m] mu/ be functionally compet5t4 ,! absurdity ( suppos+ t ! bra9 c b5efit by =m+ "p ( an unheal?y body is1 surely1 obvi\s to all4 ,det]m9$ invalids may produce spl5did "w1 z ,d>w9 did1 9 spite ( ill-heal?1 b n because ( x1 & m5 ( great m5tal en]gy w sometimes we> !mselves out prematurely by _! re/lessness2 b />vation & maltreatm5t ( ! body w n create intellect1 h[ev] morbidly x may /imulate ! imag9ation4 ,grant+ ! t5em5t ( a heal?y body1 ! education ( ! c5tral n]v\s sy/em mu/ proce$ along f\r di/9ct l9es4 ,a *ild mu/ le>n useful reflex actions1 su* z walk+2 h its association c5tres tra9$1 t x may reason quickly & correctly2 be endu$1 if x is n to live ^u a des]t isl&1 ) a s5se ( moral responsibility & e?ical pr9ciples2 & h its head /or$ ) useful facts1 f ! mean+ ( words & ! ,a ,b ,c to ! value ( ! co9age4 ,few p seem to realize h[ mu* a *ild has to le>n be=e x gets to ! ,a ,b ,c4 ,x beg9s life ) v little beyond a capacity = le>n+1 & ev5 its s5se organs tell x little until x has _h practice 9 us+ !m4 ,if baby is s un=tunate z to get a scrat* f a p91 he wriggles1 & makes ! :ole h\se aw>e ( x2 b he does n seem to h a cle> idea at all z to :]e he is hurt4 ,he has to le>n ! way ab\t 8 own body4 ,he passes 8 h& ov] 8 face1 & le>ns t he has features ) a def9ite position & magnitude2 he !n waves 8 arms 9 ! air1 & le>ns t !re is su* a ?+ z empty space2 f9ally1 he knocks 8 knuckles aga9/ ! edge ( 8 cradle1 & le>ns t !re are o!r ?+s 9 exi/5ce besides himself4 ,( c\rse1 8 eyes help him consid]ably to =m 8 ideas ( ?+s1 b 8 eyes tell him no?+ until he has le>nt h[ f> to believe !m by correct+ _! impressions by t\*4 ,he le>ns ! prop]ties ( matt] by exp]im5t1 n intuition4 ,v int]e/+ exp]im5ts h be5 made ^u p :o h be5 born bl9d1 & to :om sight has be5 giv5 late 9 life by an op]ation4 ,!y g5]ally take "s "t to appreciate _! good =tune4 ,?+s1 !y say1 are all press$ up aga9/ _! eyes1 & !y are afraid to move4 ,objects ) :i* !y h c>efully be5 made famili> be=e ! op]ation--wood5 sph]es1 cubes1 cones & prisms--!y h be5 absolutely unable to recognise by sight until !y h h&l$ !m4 ,!y h mi/ak5 sp>r[s = tea-cups1 & x is sometimes only aft] weeks t !y h sudd5ly discov]$ t pictures are some?+ m ?an a mixture ( irregul> spla%es ( col\r on a flat surface4 ,babies h to le>n to int]pret :at !y see 9 mu* ! same way1 & take long] ab\t x4 ,! *ild :o cries = ! moon is probably n s unreasonable z p ?9k4 ,he focuses 8 eyes ^u ! little1 bright1 %>ply-def9$ disc1 & x appe>s to him1 if n actually )9 arm's l5g?1 at any rate ne> en\gh to be caught ) a butt]fly-net4 ,x is only aft] he has se5 x s9k beh9d a l>ge tree on ! di/ant horizon t he ga!rs a vague idea ( its real size & remot5ess4 ,! t]m #8physical culture1' z usually appli$1 is suppos$ only to mean ! developm5t ( ! muscles & visc]a2 really x only beg9s !re4 ,aft] ! organs ( nutrition h be5 got into a heal?y /ate ! motor organs are develop$4 ,f9ally ! n]v\s sy/em %\ld be tra9$4 ,m]e muscle w n make ev5 a good runn]4 ,he mu/ practise c>efully till he c take 8 full /ride1 & d s )\t wa/+ en]gy by any ne$less movem5ts4 ,!n he mu/ make ! action :i* 8 bra9 has decid$ is ! mo/ effective = 8 build ! prop]ty ( 8 sp9al cord1 t 9 a race he may use 8 /r5g? economically1 ) 8 ?\ghts free to deal ) ! tactics ( 8 oppon5ts & ! peculi>ities ( ! c\rse1 or he w n make 8 supreme ef=t at ! mo/ advantage\s mom5t4 ,?is is only "o in/ance4 ,_m m5 hav+ a normal body develop organs ( p]ception1 n motion3 ! musician & ! w9e-ta/]1 z well z ! juggl] & ! a?lete1 are products ( physical culture4 ,ev5 ! philosoph] mu/ fo/] ! physical basis ( intellect4 ,! education ( ! n]v\s sy/em goes on all ?r\gh life2 & j z (t-repeat$ actions become automatic1 s are habits ( ?\ght =m$ :i* are almo/ z regul>2 9 fact1 we might almo/ call !m c]ebral reflexes4 ,)\t con/ant ex]cise1 m5 lose _! flexibility ( m9d z well z ( body4 ,b we h already pass$ ! b\nd>ies ( our subject1 & x is "t = u to pull up1 le/ we tr5* fur!r ^u ano!r sci5ce2 = ! /udy ( ! m9d is ! prov9ce1 n ( ! physiologi/1 b ( ! psy*ologi/4 ,,ii4 ,not)/&+ ! /range p[]s ( protoplasm1 & not)/&+ t ^! are accumulat$ & int5sifi$ 9 ! body1 z we saw 9 ! la/ *apt]1 !re are immovable limitations to vital activity4 ,?is is a fact famili> to all4 ,we c trace dim9i%+ vitality ?r\gh a s]ies ( /ages1 f slight fatigue "r up to dea? itself4 ,sleep is p]haps "o ( ! mo/ int]e/+1 ?\gh x is little und]/ood4 ,dur+ sleep & ! hypnotic trance1 we "k t ! cells ( ! hemisph]es pause 9 _! "w & *emically recruit !mselves2 t !re is an int]ruption ( consci\sness2 & t *anges occur 9 ! respiratory & circulatory1 &1 9 fact1 9 mo/ ( ! functions4 ,b exactly h[ ^! /ates are induc$ we d n "k4 ,x has be5 sugge/$ t dur+ sleep less blood passes ?r\gh ! bra92 b ?is is unlikely1 & /ill less probable is x t ! n]ve cells draw 9 _! processes & %ut up l sea-anemones1 z ano!r d>+ !ori/ suppos$4 ,we c only draw p>allels betwe5 ! cells ( ! c5tral n]v\s sy/em & any o!rs2 all ne$ re/4 ,! simple/ unicellul> animals1 :i* we h m5tion$ s (t5 already1 sp5d _! lives 9 alt]nate spells ( activity & re/4 ,9 ! ?ird essay we m5tion$ briefly ! weak5+ ( ea* successive response :5 a muscle1 9 :i* tissue fatigue has *iefly be5 /udi$1 is /imulat$4 ,be=e ! muscle contract$ x conta9$ a =m ( sug>2 :5 x is tir$ ! sug> is gone1 & has be5 replac$ by ! products ( ! *emical action by :i* ! en]gy 0 evolv$4 ,a p]iod ( re/ mu/ !n foll[1 = ! muscle to be cleans$ & repl5i%$4 ,! case ( gl&s1 describ$ 9 ,essay ,,ii41 is some:at simil>4 ,aft] ! gl& cell has dis*>g$ its f]m5t1 x mu/ sp5d "s "t secret+ a fre% /ock be=e x is ready to dis*>ge aga94 ,9 fact1 a cell seems to load itself up ) supplies1 l a locomotive ) coal1 &1 aft] work+ till ! fuel is ne>ly exhau/$1 x has to /op to take 9 m4 ,all ! cells 9 ! body re/ at times2 ev5 ! cells ( ! he>t1 c>efully z !y are n\ri%$ & incessant z _! "w seems1 re/ betwe5 ea* beat1 & ! cells ( ! n]v\s sy/em =m no exception4 ,! bra9 no less ?an ! body requires p]iodic re/s to r5ew its *emical /ores1 & ^! re/s h to be all ! long]1 z dur+ ! wak+ h\rs ! bra9 works h>d] & less int]mitt5tly ?an any o!r organ4 ,x is only because ! bra9 is ! seat ( consci\sness & ! s\rce ( volunt>y movem5ts t ^! ph5om5a are susp5d$ dur+ sleep4 ,dea? may seem at fir/ sight a v simple affair1 ! break+ up ( protoplasm into simpl] non-liv+ comp\nds2 b ! dea? ( ! body is any?+ b simple--9 fact1 x is n always easy to say :5 ! body is dead4 ,usually1 h[ev]1 x is consid]$ dead :5 ! c5tral n]v\s sy/em has succumb$1 ?\gh ! muscles may cont9ue to live = sev]al h\rs4 ,dea? may beg9 9 _m ways4 ,! loss ( "s organs w br+ dea? only aft] a consid]able "t1 :ile ! failure ( o!rs di/urbs its economy fatally1 & causes an almo/ imm$iate cessation ( ! vital functions4 ,any int]f]5ce ) ! normal conditions ( ! bra91 he>t1 or lungs is v dang]\s1 & x is injury or disease ( "o ( ! ?ree :i* puts an end to mo/ m5's tr\bles4 ,if ! bra9 weak5s s t x no long] keeps ! he>t beat+ or ! muscles1 :i* fill & empty ! lungs1 to _! duties1 ! body1 = obvi\s reasons1 c no long] keep up ! cycle ( *anges we call life4 ,on ! o!r h&1 if ! lungs _c oxidize ! blood1 or ! he>t drive fre% pabulum to ! bra91 t organ collapses imm$iately1 &1 if a /ream ( pure blood is n quickly re/or$ to x1 dies4 ,no return ( ! circulation c !n re/ore x2 ! dea? ( ! re/ ( ! animal mu/ foll[4 ,be+ ! mo/ delicate1 ! cells ( ! c5tral n]v\s sy/em usually die fir/1 & we !n say t ! man is dead4 ,s ! body may be1 b mu* ( ! protoplasm ( :i* x is compos$--:ole organs1 9 fact--rema9s alive2 ! muscles w respond to electrical /imulation1 & 9 case "s p may dispute t ?is is a sign ( life1 if pieces ( 8 sk9 be remov$ & graft$ into ano!r p]son1 !y w gr[ !re1 produce hair1 & become1 9 fact1 a "p ( ! new body4 ,?is !y c\ld n possibly d if !y 7 dead2 we _c end[ inanimate matt] ) life4 ,z dea? creeps on ov] ! tissues1 ! leucocytes die1 & 9 do+ s =m a f]m5t :i* solidifies "o ( ! proteids dissolv$ 9 ! blood1 s t ! famili> clott+ takes place4 ,by a simil> process c]ta9 con/itu5ts ( ! muscles are also clott$1 ! muscles /iff5+ & pass+ into :at is te*nically1 b also pretty g5]ally1 kn[n z rigor mortis4 ,rigor is said to set 9 soon aft] dea? if ! body is kept 9 a w>m place1 or if dea? has be5 prec$$ by viol5t ex]cise2 b dea? 9 ?is in/ance means only ! dea? ( ! body4 ,x is at ! precise mom5t t a muscle fibre dies t x passes into rigor4 ,by keep+ x cool1 s t ! processes ( life may g on sl[ly1 especially if x be 9 a heal?y condition1 its dea? may be def]r$ = h\rs2 :ile1 on ! o!r h&1 at ! end ( a sev]e & protract$ battle1 exhau/$ soldi]s sometimes die in/antane\sly on be+ %ot1 & are f\nd fix$ 9 ! position 9 :i* ! fatal bullet f\nd !m--on _! knees1 ) gun to %\ld]1 9 ! act ( fir+4 ,b if ! mann] ( dea? is n to be lightly dealt )1 its causes are /ill m obscure4 ,x seems natural en\gh t p %\ld be kill$ by viol5ce or by diseases ) an ext]nal or septic orig91 or ev5 by "o p>ticul> organ we>+ out & involv+ ! :ole body 9 ! fate ( its "p4 ,b :y %\ld p die ( old age8 ,:y %\ld _! vitality ebb till !y quietly g out8 ,life is a me*anical cycle ( *anges4 ,= a "t ev5 aft] x has /opp$ gr[+1 ! body replaces :at x wa/es1 & keeps itself 9 a condition ( equilibrium4 ,:y1 !n1 )\t any app>5t ext]nal cause1 does x1 aft] a m or less circumscrib$ p]iod1 ent] into a decl9e8 ,&1 f9ally1 c\ld we1 by tak+ ! prop] precautions1 delay or prev5t old age & dea?8 ,9 ! fir/ place1 reg>d+ protoplasm z a *emical /ructure1 :y1 if kept "u fav\rable conditions1 %\ld x ev] break d[n8 ,we h no reason to suppose t x ne$4 ,x is h>d to see h[ ! m9ute animals1 consi/+ ( only "o cell1 c die ( old age1 provid$ t no injuri\s influ5ce be br\ght to be> ^u !m4 ,:5 an individual has gr[n to a c]ta9 size1 x divides 9 two1 & ea* ent]s ^u life afre%4 ,:y1 !re=e1 %\ld n all ! cells ( ! body cont9ue to r5ew _! y\?8 ,! reason :y ! body c only la/ a c]ta9 "t1 9 spite ( ! _m quacks ) recipes = immortality--recipes includ+ su* items z ! avoidance ( all tr\ble1 worry1 or "w--mu/ rema9 a secret until we "k ! *emical basis ( life4 ,x seems to lie 9 ! cell4 ,if a unicellul> organism1 z describ$ above1 be plac$ 9 a vessel ( /]iliz$ wat] & left to live alone "u o!rwise ideal conditions1 x w />t divid+ & multiply+1 z ?\gh x meant to reproduce itself indef9itely4 ,aft] a "t1 h[ev]1 ! %oal beg9s to det]iorate2 ea* successive g5]ation is feebl] ?an ! la/1 & ev5tually all die4 ,if1 h[ev]1 be=e ?is happ5s "o ( ! effete cells be plac$ 9 ano!r vessel ) a simil> individual d]iv$ f a diff]5t ance/or1 ! two w fuse & =m a s+le fre% animal ) entirely re/or$ vig\r1 ready to multiply to ! same ext5t z ei!r ( its orig9al ance/ors4 ,a few individuals ( a diff]5t /ock w 9 ?is way revivify ! :ole brood4 ,!re is1 !re=e1 evid5tly some?+ 9 ! cell :i* we>s out aft] x has divid$ a c]ta9 numb] ( times--some?+ :i* mu/ be re/or$ by bl5d+ ) cells ( ano!r /ra94 ,:at ?is is we d n "k1 & p]haps nev] %all4 ,! mo/ we "k is t x seems to be some?+ inh]5t 9 ! nucleus1 n ! ma9 body ( protoplasm ( ! cell1 = "s unicellul> animals d n fuse1 "u ! circum/ances relat$ above1 b ex*ange only pieces ( _! nuclei1 & yet d]ive ! advantages ( mutually increas$ vitality4 ,b if we apply ! fact to our conception ( ! body z a va/ colony ( cells ) a common orig91 we f9d t x has an important be>+ ^u ! duration ( its life4 ,! s+le eggcell :i* gave rise to our s*ematic embryo 9 ,diagram #c1 ,fig4 #a1 0 =m$ by ! fusion ( two cells %$ by two di/9ct animals4 ,h[ ?is "o cell gr[s & multiplies by division is r\ghly %[n 9 ! diagram & ^? imm$iately foll[+ x2 b ?\gh ! cells d n sep>ate1 b hang toge!r & =m a body1 x is obvi\s t ! colony only am\nts to a %oal ( unicellul> organisms1 l t describ$ above z gr[+ weak] ) ea* successive division unless bl5d$ ) individuals ( a diff]5t /ock4 ,?is _c be done 9 ! body2 :at w\ld become ( our individuality ev5 if su* a ?+ 7 possible8 ,! body c help to give rise to new bodies1 b its own tissues mu/ we> out1 & :5 ! colony ( cells is exhau/$ x mu/ die4 ,c>eful diet & regul> habits1 ! m9imum ( we> & te>1 may enable ! body to run its full t]m2 b !y _c l5g!n ! lease ( life4 ,s f> only c ! physiologi/ take u4 ,physiology may tea* u h[ to develop our p[]s & economize our /r5g?2 x is already beg9n+ to conv]t m$ic9e f an art into a sci5ce2 x w1 x is to be hop$1 %ortly "w a revolution 9 our at pres5t b>b>\s ideas ( h[ to re> & educate *ildr52 x may1 9 %ort1 tea* u h[ to make ! v mo/ ( life & die easily2 b n until1 if ev]1 x und]/&s ! physical basis ( life1 & p]haps n ev5 !n1 w x be likely to succe$ 9 prolong+ a man's days mu* beyond ! traditional f\rscore ye>s4 ,,conclusion4 ,:ile ! physiologi/ is quietly work+1 mak+ sl[ b sure progress1 8 critics1 fri5dly & o!rwise1 buzz ab\t him l bees4 ,!re are "s :o are 9 a *ronic /ate ( excitem5t1 expect+ a revolutioniz+ discov]y f h\r to h\r2 !re are o!rs :o assure him t he has rea*$ ! limit ( human p[]s ( compreh5sion1 & c nev] "k mu* m ?an he does to-day2 &1 la/ly1 !re are ^? :o decl>e t he has done next to no?+1 & t 8 utmo/ endeav\rs h fail$ to effect any real result1 & leave all ! important secrets ( life unt\*$4 ,no "o kn[s bett] ?an ! physiologi/ h[ mi/ak5 is ! ov]sangu9e class fir/ m5tion$4 ,9 no dep>tm5t ( sci5ce1 c]ta9ly n 9 physiology1 is x possible to rea* ! top ( ! ladd] by a b\nd2 ea* rung mu/ be ma/]$ 9 ord]4 ,9 invad+ ! unkn[n l& ! sci5ti/ mu/ ?or\ghly explore & effectively occupy z he advances4 ,he mu/ annex z he goes along2 ! fly+ columns :i* try to rea* ! enemy's capital by a da% are nev] he>d ( aga94 ,9 physiology ! publication ( ! v>i\s /eps is sometimes )held until ! objective has be5 rea*$1 b our k ( life is l ,solomon's temple3 a ,david collects ! mat]ial1 & 8 successor raises ! edifice4 ,! _w wat*es x gr[4 ,x is n l ^? bewild]+ & un/able palaces ( ! #8,arabian ,nights1' built by g5ii 9 a s+le night1 & (t5 vani%+ z my/]i\sly4 ,9 e age !re h exi/$ p :o decl>e t m5 c nev] "k m ?an !y d at ! mom5t4 ,!re 7 pl5ty ( !m :5 ! sci5ce ( physiology 0 unborn1 & !re w be pl5ty m ( !m a hundr$ ye>s h5ce2 only !n !y w ref] ) tol]ant amusem5t to ! crude & elem5t>y ideas ( _! pr$ecessors at ! beg9n+ ( ! tw5tie? c5tury4 ,! ?ird class1 :o take su* delight 9 m9imiz+ ! a*ievem5ts ( ! physiologi/1 usually are f\nd1 if anyone takes !m s]i\sly1 to "k v little ei!r ab\t ! sci5ce ( physiology itself or ! hi/ory ( its gr[?4 ,i leave ! read] to =m 8 own v]dict ^u ! value ( ! results obta9$ f _! exce$+ly brief & sket*y description 9 ?is little volume1 ) ! rem>k t ! sci5ce is b>ely m ?an ?ree-qu>t]s ( a c5tury old1 & ! mo/ important additions to our k h be5 made )9 ! la/ tw5ty ye>s4 ,!re 71 p>adoxical z x may s\nd1 great physiologi/s be=e !n2 ! "w ( ,h>vey1 :o ?ree c5turies ago discov]$ ! circulation ( ! blood1 is above all praise2 b h[ nebul\s mu/ h be5 _! ideas may be se5 f ! foll[+ facts3 ,x 0 only at ! beg9n+ ( ! n9ete5? c5tury t ! atomic !ory ( matt] 0 =mulat$2 x 0 n until tw5ty ye>s lat] t ! _w 0 />tl$ by a d>+ *emi/ :o %[$ t organic comp\nds obey$ ! same natural laws z inorganic2 & n until t5 ye>s lat] 0 ! cellul> /ructure ( animals1 ! gr\ndwork 9 all /udy ( life1 recognis$4 ,ev5 :5 ! sci5ce 0 set ^u firm f\ndations1 progress 0 at fir/ necess>ily sl[3 ! organic *emi/ took "s "t 9 exam9+ & classify+ ! comp\nds met ) 9 ! body--he has n f9i%$ yet2 & ev5 :5 ! cell !ory 0 grasp$1 x requir$ mu* +5uity & long pati5ce to devise ways ( exam9+ organs "u ! microscope1 s t _! /ructure c\ld be made out4 ,! microscope itself 0 a poor toy fifty ye>s ago1 magnify+ a diamet] t5 times :]e n[ x magnifies a hundr$1 & giv+ only a dim & di/ort$ image4 ,! p]fect+ ( ! microscope1 & ! introduction ( an/hetics & antiseptics1 h l$ to enorm\s /rides be+ made )9 ! la/ two decades4 ,! result ( ! advance 9 *emical k1 & ! introduction ( fre% aids to inve/igation1 l$ to ! disc>d+ ( vital =ce z a work+ hypo!sis4 ,vital =ce 0 ! bane ( ! e>li] biologi/s4 ,!y made x acc\ntable = all !y c\ld n und]/&1 & ) ?is re/atem5t ( _! difficulties--a re/atem5t :i* !y call$ an explanation--refra9$ f fur!r rese>*4 ,b :5 x 0 f\nd t _m ( ^! inexplicable ph5om5a1 ?\gh refractory1 yield$ to c>eful /udy1 & c\ld be expla9$ by *emical & physical laws1 ! physiologi/ ceas$ to say ( !m1 #8,!y are problems connect$ ) ,life1 & !re=e expla9$ by ,vital ,=ce1 :i* is pa/ man's und]/&+1' & frankly admitt$ t !re 7 _m ?+s :i* he did n z yet fa?om4 ,rec5tly a vitali/ic s*ool has cropp$ up aga91 decl>+ t all t x _c und]/& mu/ infallibly be due to "s occult ag5cy4 ,x %[s rem>kable vitality 9 surviv+ ! %ocks ( successive discov]ies4 ,turn+ once m to ! pres5t day1 we w conclude ) a brief glance r\nd a physiological laboratory1 & see by :at me?ods ! physiologi/ is prep>+ future surprises4 ,! *emical dep>tm5t fir/ claims our att5tion4 ,! imports & exports ( animals are c>efully balanc$1 & ! *anges produc$ 9 ! food exam9$4 ,! animal is enclos$ 9 an airtight *amb]1 air ( kn[n composition be+ pump$ into x1 & ! air :i* escapes analyz$4 ,! animal mo/ us$ = ?is exp]im5t is man himself1 s9ce he w take re/ & ex]cise to ord]1 ! latt] usually on ! treadmill1 by :i* x c be also measur$1 & c be reli$ ^u n to :ile away ! t$ium ( 8 imprisonm5t by gnaw+ holes 9 ! walls or upsett+ 8 food4 ,all ! sub/ances us$ z food1 f\nd 9 or excret$ by ! body1 are be+ ?or\ghly /udi$2 b x %\ld be rememb]$ t ?is is *emi/ry1 n physiology4 ,physiology is only conc]n$ ) protoplasm1 & ! physiologi/ :o goes deeply into ! *emi/ry ( non-liv+ matt] has to discipl9e 8 m9d aga9/ =gett+ its ceaseless *ange1 & try+ to reg>d x z ?\gh x 7 con/ant4 ,! actual *emi/ry ( protoplasm w be a v h>d nut to crack1 & may defy u until we c depict molecules z well actually z we n[ c symbolically4 ,"s idea ( ! difficulty may be =m$ if we consid] t x is impossible to imag9e a pure sample4 ,f ! re/less activity :i* is ! condition ( its exi/5ce1 x is always work+ *anges 9 its surr\nd+1 always mix$ ) raw mat]ial1 & always mask$ by ! products ( its own metabolism4 ,ev5 if we )hold ! =m]1 x consumes its own sub/ance until ! mom5t ( dea?4 ,x does n ev5 look homog5e\s "u ! microscope4 ,be=e1 h[ev]1 we c pursue ! *emical me?ods fur!r1 x w be necess>y to describe ! hi/ological4 ,! read] may h already wond]$ h[ we manag$ to f9d out s mu* ab\t ! cellul> /ructure ( ! body4 ,x is no easy matt] to cut up s(t tissue1 ( ! consi/5cy ( an unboil$ egg1 into ?9 slices :i* c be exam9$ "u ! microscope4 ,x is done 9 ! foll[+ mann]3 ,! bloodvessels ( ! fre%ly kill$ body are inject$ ) a fluid :i* in/antane\sly kills & fixes ! cells 9 mu* ! same way z an egg is fix$ by be+ h>d-boil$4 ,! natural %ape ( ! cells is ?us pres]v$1 & ! loss ( any ( _! *emical con/itu5ts by putrefaction prev5t$4 ,! piece ( organ is !n impregnat$ ) & ca/ 9 ! middle ( a solid block ( p>aff9 wax1 :i* is put into a ma*9e & %av$ up into ?9 slices1 ab\t #dj1jjj to ! in* sometimes4 ,"o ( ^! %av+s is !n /uck ^u a glass slide1 & on ! wax be+ dissolv$ away ) "s su* sub/ance z b5z9e1 a section ( ! tissue1 ab\t "o cell ?ick1 is left on ! glass ready = microscopic survey4 ,to d any?+ l ju/ice to ! hi/ological me?ods w\ld require a volume 9 itself4 ,:5 ! sections are fix$ ^u slides1 !y are treat$ ) a numb] ( reag5ts to %[ _! *emical & /ructural peculi>ities4 ,"o section is /a9$ specially to %[ ! nucleus2 ano!r to %[ ! c5trosome2 ano!r zymog5 granules1 etc4 ,&1 z all ^! _c be %[n at _! be/ 9 "o cell1 ! diff]5tly treat$ sections h to be sep>ately drawn or photograph$1 & ! typical /ructure compil$ f sev]al4 ,by c>eful /a9+1 ! *emical composition ( ! diff]5t p>ts ( ! cell is be+ work$ out1 & ! effects ( re/1 activity1 fe$+1 & o!r influ5ces1 /udi$4 ,take z an example ! effects ( a meal4 ,a numb] ( animals ( ! same litt] are f$ toge!r out ( ! same tr\gh4 ,"o has be5 kill$ be=e ! meal1 & ! re/ are kill$ at int]vals divid+ ! "t :i* mu/ int]v5e be=e _! next fe$+-"t comes r\nd4 ,s]ies ( sections f _! organs are prep>$1 "o f ea* animal be+ m\nt$ 9 ord] ^u ! same piece ( glass1 dipp$ 9 ! same reag5ts1 & exam9$ "u ! same microscope4 ,f a numb] ( ^! sections ! progressive effects ( a meal ^u ea* ( ! sev]al con/itu5ts ( ! cell are trac$ out1 & "s ( ! *emical processes d$uc$4 ,turn+ to ! physical side ( physiology1 x is unnecess>y "h to say m ab\t ! means employ$ = /udy+ ! prop]ties ( muscle & n]ve ?an t _m ( ! ph5om5a occur ) su* extreme rapidity t !y c only be p]ceiv$ by ! photographic plate4 ,9 ! /udy ( ! l>ge organs1 ! physiologi/ f9ds a fasc9at+ employm5t 9 devis+ models 9 :i*1 s f> z possible1 all ! physical conditions are reproduc$1 & ?is n only = ! b5efit ( 8 pupils1 b to help himself 9 p]ceiv+ _! mean+4 ,too mu* reliance mu/ n be plac$ on ^! models1 ( c\rse1 b !y h add$ consid]ably to our k ( ! eye & ?roat4 ,x requires no great imag9ation to p]ceive ! difficulties :i* lie 9 ! way ( /udy+ ! n]v\s sy/em4 ,trac+ n]ve fibres "u ! microscope ?r\gh int]m9able s]ies ( sections is a lab\r :i* c nei!r be hurri$ nor scamp$4 ,x is greatly aid$ by pa?ological specim5s4 ,an animal :i* has be5 ?r\gh life ) only "o eye w obvi\sly h c5tral organs ( vision %[+ wide contra/s4 ,^? connect$ ) ! bl9d eye w be undevelop$1 because nev] us$1 :ile ! correspond+ lobes ( ! bra9 connect$ ) ! o!r eye w %[ ! effects ( do+ extra "w4 ,_m ( ! problems :i* meet ! physiologi/ c only be solv$ by exp]im5t+ ^u a live animal1 & ^! exp]im5ts =m by no means ! easie/ "p ( 8 "w4 ,! animal mu/ be kept1 s f> z possible1 "u physiological conditions--t is to say1 free f pa9 & fright & unpoison$ by drugs4 ,?anks1 h[ev]1 to an ext5sive k & skilful use ( an/hetics1 ! ob/acles to ?is me?od ( inve/igation h be5 ov]come1 & its results h prov$ v pr(itable4 ,! abs5ce ( pa9 is a v important factor 9 an exp]im5t1 & ev5 if ! physiologi/ took ! wanton delight 9 inflict+ suff]+ :i* ! imag9ation ( 8 enemies attributes to him1 he w\ld h to re/ra9 its indulg5ce 9 8 laboratory1 or =ego ! hope ( ev5 mod]ate success4 ,9 ?is c\ntry1 moreov]1 ! ,gov]nm5t w n all[ su* exp]im5ts )\t its express p]mission1 & ! lic5se is v rightly only grant$ to m5 ^: rese>*es promise an adequate return1 & :o are likely to conduct !m humanely & successfully4 ,physiological rese>* is n a hobby to be lightly tak5 up4 ,x is n "o m]ry r\nd ( excit+ tussles ) tortur$ & infuriat$ cats & dogs2 on ! contr>y1 x entails ardu\s lab\r & ne$s inf9ite pati5ce4 ,! exp]im5ts1 (t5 t$i\s 9 !mselves1 h to be repeat$ aga9 & aga9 9 z _m diff]5t ways z possible1 until e slight diff]5ce 9 result c be acc\nt$ =2 & ! c]ta9ty t bo? ! me?ods us$ & ! int]pretation giv5 w1 :5 publi%$1 receive ! close/1 & n 9 e case ! fri5dlie/1 scrut9y by o!r memb]s ( ! pr(ession s]ves z an admirable corrective to jump+ at conclusions4 ,x is1 h[ev]1 an occupation ( absorb+ int]e/1 & ! physiologi/ feels amply repaid if he c ?9k t 8 lab\rs h add$1 no matt] h[ little1 to t control ov] ,nature :i* ! sev]e conditions ( mod]n life make e day m press+ly necess>y4 ,,index ,a4 ,abdom9al circulation1 #ed ,absorption1 #be ,acid1 hydro*loric1 #bc ,aff]5t sy/em ( n]ves1 #ib ,alcohol1 #ie ,alim5t>y canal1 l5g? (1 #ai movem5ts (1 #df orig9 (1 #ag /ructure (1 #df ,amba1 #af ,amboid movem5t1 #ca ,am\nt ( food1 #ae1 #if ,animalcula 7unicellul> micro-organisms71 #e1 #h1 #af1 #ca1 #ajb1 #aje ,aorta1 #ea ,arm1 #eg ,art]y1 #dh ,association c5tres1 #ia ,a?letes1 #ih ,atom1 #b ,auditory me*anism1 #gd ,auricles1 #di ,b4 ,bact]ia1 #bc1 #dd ,beaumont1 #be ,bile1 #bd1 #fb ,bl9d1 exp]im5ts ) !1 #ajj ,blood1 #bf circulation ( !1 #dh clott+ aft] dea?1 #ajd corpuscles1 #bi1 #de c\rse ( !1 #bg1 #ee pressure1 #ea1 #ff ,body1 !1 #i1 #id ,boils1 #de ,bone1 #cf1 #ef1 #ih ,bra91 #fc1 #gi1 #ajb ,brea?+1 #be1 #eb1 #hb1 #ig ,c4 ,canals1 semicircul>1 #gg ,capill>ies1 #dh ,c>bohydrate1 #ad1 #if dige/ion (1 #bb ,c>bon1 #aa1 #ac ,c>bonic acid gas1 #ac1 #be ,c>tilage1 #cf ,cavity ( ! body1 #dc ,cell1 #d a *emical laboratory1 #f division (1 #cb1 #aje exhau/ion (1 #ajb movem5ts (1 #e1 #ca n]ve1 #fj1 #hg sp9al ganglion1 #fc ,c5tres1 n]v\s1 #fc1 #gh1 #hh1 #ia ,c5trosome1 #ca ,c]ebellum1 #hd ,c]ebral cortex1 #hf hemisph]es1 #he ,*emical comp\nds1 #b ne$s ( body1 #aa ,*emi/ry ( ! body1 #h ,*ords1 vocal1 #ic ,cilia1 #cc ,circulation1 #bg1 #ig c\rse (1 #bh1 #ee me*anism (1 #dh ,circulat+ fluids1 #bf ,clott+ ( blood1 #ajd ,co*lea1 #gf ,cold1 #hc ,collag51 #bd1 #ce1 #if ,comp\nds1 *emical1 #b ,conductivity ( protoplasm1 #ei ,connective tissue1 #bd1 #ce1 #if ,cons]vation ( en]gy1 #ib ,contraction ( he>t1 #di ( muscle1 #cd ,cook+1 #if ,cord1 sp9al1 #fc1 #gh ,corpuscles1 r$ blood1 #bi :ite blood 7leucocytes71 #de ,cortex1 #hf ,c\gh1 #fe1 #fg ,d4 ,dea?1 #ajc ,diaphragm1 #eb1 #ig ,diet1 #aa1 #ie ,dige/ion1 #aa by body1 #bb by cell1 #af ,doctor1 ix ,drum ( e>1 #ge ,e4 ,e>1 #gd ,education1 #ii ,eff]5t sy/em ( n]ves1 #ib ,egg1 :ite (1 #ac ,electric manife/ations 9 tissues1 #dj organs ( fi%1 #db /imulation ( tissues1 #cg1 #hh ,embryo1 developm5t (1 #ag ,endolymph1 #gd ,enzyme1 #ae ,epilepsy1 #hi ,equilibrium1 #ff1 #hd ,ex]cise1 #ig ,eye1 #gc education (1 #ajj protection (1 #fe ,f4 ,fa9t+1 #ff ,fat1 #ad1 #bd1 #bg ,fatigue1 #dj1 #ajb ,f]m5ts1 #ae ,fibres1 connective tissue1 #ce muscle1 #cd n]ve1 #db1 #fj ,fibrils1 muscle1 #ce ,fi%1 electric1 #db ,food1 #aj1 #ie am\nt (1 #ae1 #if vacuole1 #af ,=ehead1 #ia ,frog exp]im5ts on muscle1 #cg reflexes1 #fh ,g4 ,ganglion1 sp9al1 #fb ,ga/ric juice1 #bc ,gelat91 #bd1 #ce1 #if ,gl& cells1 #ba ,gl&s1 orig9 (1 #bj saliv>y1 #bb sweat1 #ga te>1 #fe ,h4 ,hmoglob91 #bi ,hair1 #gj ,h>vey1 #ajh ,head1 #gi ,he>+1 #gd ,he>t1 #dh1 #ff ,heat1 production (1 #ac regulation (1 #hc ,hi/ological me?ods1 #aaj ,huxley1 #g ,hydro*loric acid1 #bc ,i4 ,int]nal secretion1 #bi ,inte/9e1 movem5ts (1 #dg ,involunt>y movem5ts1 #fe muscle1 #cd ,iron1 #ie ,k4 ,kidneys1 #bi1 #ie ,l4 ,labyr9?s ( e>1 #gd ,leucocytes1 #db ,limbs1 #ef ,liv]1 #bd circulation ?r\gh1 #bg1 #ed ,liv+ matt]1 #a ,localization ( function 9 ! bra91 #hf1 #hh ,lungs1 #eb1 #ic absorption by1 #be ,lymph1 #bf circulation (1 #bg1 #dh ,m4 ,m>%all's fibrils1 #ce ,meat 9 diet1 #ae1 #ie ,m$ic9e1 ix ,m$ulla 7h9d-bra971 #hb ,memory1 #ia ,micro-organisms1 #e1 #h1 #af1 #ca1 #ajb1 #aje ,microscope 7hi/ological me?ods71 #aaj ,milk1 #ie ,mixture1 #c ,molecule1 #b ,m\?1 #gi ,muscle1 #cd h[ /udi$1 #cg ( alim5t>y canal1 #df1 #ie ,muscles1 #ig ( limbs1 #ef /iff5+ at dea? 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