第1章

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OFthepartsofanimalssomearesimple:towit，allsuchasdivideintopartsuniformwiththemselves，asfleshintoflesh；othersarecomposite，suchasdivideintopartsnotuniformwiththemselves，as，forinstance，thehanddoesnotdivideintohandsnorthefaceintofaces。

Andofsuchasthese，somearecallednotpartsmerely，butlimbsormembers。Sucharethosepartsthat，whileentireinthemselves，havewithinthemselvesotherdiverseparts:asforinstance，thehead，foot，hand，thearmasawhole，thechest；fortheseareallinthemselvesentireparts，andthereareotherdiversepartsbelongingtothem。

Allthosepartsthatdonotsubdivideintopartsuniformwiththemselvesarecomposedofpartsthatdososubdivide，forinstance，handiscomposedofflesh，sinews，andbones。Ofanimals，someresembleoneanotherinalltheirparts，whileothershavepartswhereintheydiffer。Sometimesthepartsareidenticalinformorspecies，as，forinstance，oneman\'snoseoreyeresemblesanotherman\'snoseoreye，fleshflesh，andbonebone；andinlikemannerwithahorse，andwithallotheranimalswhichwereckontobeofoneandthesamespecies:forasthewholeistothewhole，soeachtoeacharethepartsseverally。Inothercasesthepartsareidentical，saveonlyforadifferenceinthewayofexcessordefect，asisthecaseinsuchanimalsasareofoneandthesamegenus。By\'genus\'I

mean，forinstance，BirdorFish，foreachoftheseissubjecttodifferenceinrespectofitsgenus，andtherearemanyspeciesoffishesandofbirds。

Withinthelimitsofgenera，mostofthepartsasaruleexhibitdifferencesthroughcontrastofthepropertyoraccident，suchascolourandshape，towhichtheyaresubject:inthatsomearemoreandsomeinalessdegreethesubjectofthesamepropertyoraccident；andalsointhewayofmultitudeorfewness，magnitudeorparvitude，inshortinthewayofexcessordefect。Thusinsomethetextureofthefleshissoft，inothersfirm；somehavealongbill，othersashortone；somehaveabundanceoffeathers，othershaveonlyasmallquantity。Ithappensfurtherthatsomehavepartsthatothershavenot:forinstance，somehavespursandothersnot，somehavecrestsandothersnot；butasageneralrule，mostpartsandthosethatgotomakeupthebulkofthebodyareeitheridenticalwithoneanother，ordifferfromoneanotherinthewayofcontrastandofexcessanddefect。For\'themore\'and\'theless\'mayberepresentedas\'excess\'or\'defect\'。

Onceagain，wemayhavetodowithanimalswhosepartsareneitheridenticalinformnoryetidenticalsavefordifferencesinthewayofexcessordefect:buttheyarethesameonlyinthewayofanalogy，as，forinstance，boneisonlyanalogoustofish-bone，nailtohoof，handtoclaw，andscaletofeather；forwhatthefeatherisinabird，thescaleisinafish。

Theparts，then，whichanimalsseverallypossessarediversefrom，oridenticalwith，oneanotherinthefashionabovedescribed。

Andtheyaresofurthermoreinthewayoflocaldisposition:formanyanimalshaveidenticalorgansthatdifferinposition；forinstance，somehaveteatsinthebreast，othersclosetothethighs。

Ofthesubstancesthatarecomposedofpartsuniform(orhomogeneous)withthemselves，somearesoftandmoist，othersaredryandsolid。Thesoftandmoistaresucheitherabsolutelyorsolongastheyareintheirnaturalconditions，as，forinstance，blood，serum，lard，suet，marrow，sperm，gall，milkinsuchashaveitfleshandthelike；andalso，inadifferentway，thesuperfluities，asphlegmandtheexcretionsofthebellyandthebladder。Thedryandsolidaresuchassinew，skin，vein，hair，bone，gristle，nail，horn(atermwhichasappliedtothepartinvolvesanambiguity，sincethewholealsobyvirtueofitsformisdesignatedhorn)，andsuchpartsaspresentananalogytothese。

Animalsdifferfromoneanotherintheirmodesofsubsistence，intheiractions，intheirhabits，andintheirparts。Concerningthesedifferencesweshallfirstspeakinbroadandgeneralterms，andsubsequentlyweshalltreatofthesamewithclosereferencetoeachparticulargenus。

Differencesaremanifestedinmodesofsubsistence，inhabits，inactionsperformed。Forinstance，someanimalsliveinwaterandothersonland。Andofthosethatliveinwatersomedosoinoneway，andsomeinanother:thatistosay，someliveandfeedinthewater，takeinandemitwater，andcannotliveifdeprivedofwater，asisthecasewiththegreatmajorityoffishes；othersgettheirfoodandspendtheirdaysinthewater，butdonottakeinwaterbutair，nordotheybringforthinthewater。Manyofthesecreaturesarefurnishedwithfeet，astheotter，thebeaver，andthecrocodile；somearefurnishedwithwings，asthediverandthegrebe；somearedestituteoffeet，asthewater-snake。Somecreaturesgettheirlivinginthewaterandcannotexistoutsideit:butforallthatdonottakeineitherairorwater，as，forinstance，thesea-nettleandtheoyster。Andofcreaturesthatliveinthewatersomeliveinthesea，someinrivers，someinlakes，andsomeinmarshes，asthefrogandthenewt。

Ofanimalsthatliveondrylandsometakeinairandemitit，whichphenomenaaretermed\'inhalation\'and\'exhalation\'；as，forinstance，manandallsuchlandanimalsasarefurnishedwithlungs。

Others，again，donotinhaleair，yetliveandfindtheirsustenanceondryland；as，forinstance，thewasp，thebee，andallotherinsects。Andby\'insects\'Imeansuchcreaturesashavenicksornotchesontheirbodies，eitherontheirbelliesoronbothbacksandbellies。

Andoflandanimalsmany，ashasbeensaid，derivetheirsubsistencefromthewater；butofcreaturesthatliveinandinhalewaternotasingleonederivesitssubsistencefromdryland。

Someanimalsatfirstliveinwater，andbyandbychangetheirshapeandliveoutofwater，asisthecasewithriverworms，foroutofthesethegadflydevelops。

Furthermore，someanimalsarestationary，andsomeareerratic。

Stationaryanimalsarefoundinwater，butnosuchcreatureisfoundondryland。Inthewateraremanycreaturesthatliveincloseadhesiontoanexternalobject，asisthecasewithseveralkindsofoyster。And，bytheway，thespongeappearstobeendowedwithacertainsensibility:asaproofofwhichitisallegedthatthedifficultyindetachingitfromitsmooringsisincreasedifthemovementtodetachitbenotcovertlyapplied。

Othercreaturesadhereatonetimetoanobjectanddetachthemselvesfromitatothertimes，asisthecasewithaspeciesoftheso-calledsea-nettle；forsomeofthesecreaturesseektheirfoodinthenight-timelooseandunattached。

Manycreaturesareunattachedbutmotionless，asisthecasewithoystersandtheso-calledholothuria。Somecanswim，as，forinstance，fishes，molluscs，andcrustaceans，suchasthecrawfish。Butsomeoftheselastmovebywalking，asthecrab，foritisthenatureofthecreature，thoughitlivesinwater，tomovebywalking。

Oflandanimalssomearefurnishedwithwings，suchasbirdsandbees，andthesearesofurnishedindifferentwaysonefromanother；othersarefurnishedwithfeet。Oftheanimalsthatarefurnishedwithfeetsomewalk，somecreep，andsomewriggle。Butnocreatureisableonlytomovebyflying，asthefishisableonlytoswim，fortheanimalswithleathernwingscanwalk；thebathasfeetandthesealhasimperfectfeet。

Somebirdshavefeetoflittlepower，andarethereforecalledApodes。Thislittlebirdispowerfulonthewing；and，asarule，birdsthatresembleitareweak-footedandstrongwinged，suchastheswallowandthedrepanisor(？)Alpineswift；forallthesebirdsresembleoneanotherintheirhabitsandintheirplumage，andmayeasilybemistakenoneforanother。(Theapusistobeseenatallseasons，butthedrepanisonlyafterrainyweatherinsummer；forthisisthetimewhenitisseenandcaptured，though，asageneralrule，itisararebird。)

Again，someanimalsmovebywalkingonthegroundaswellasbyswimminginwater。

Furthermore，thefollowingdifferencesaremanifestintheirmodesoflivingandintheiractions。Somearegregarious，somearesolitary，whethertheybefurnishedwithfeetorwingsorbefittedforalifeinthewater；andsomepartakeofbothcharacters，thesolitaryandthegregarious。Andofthegregarious，somearedisposedtocombineforsocialpurposes，otherstoliveeachforitsownself。

Gregariouscreaturesare，amongbirds，suchasthepigeon，thecrane，andtheswan；and，bytheway，nobirdfurnishedwithcrookedtalonsisgregarious。Ofcreaturesthatliveinwatermanykindsoffishesaregregarious，suchastheso-calledmigrants，thetunny，thepelamys，andthebonito。

Man，bytheway，presentsamixtureofthetwocharacters，thegregariousandthesolitary。

Socialcreaturesaresuchashavesomeonecommonobjectinview；

andthispropertyisnotcommontoallcreaturesthataregregarious。Suchsocialcreaturesareman，thebee，thewasp，theant，andthecrane。

Again，ofthesesocialcreaturessomesubmittoaruler，othersaresubjecttonogovernance:as，forinstance，thecraneandtheseveralsortsofbeesubmittoaruler，whereasantsandnumerousothercreaturesareeveryonehisownmaster。

Andagain，bothofgregariousandofsolitaryanimals，someareattachedtoafixedhomeandothersareerraticornomad。

Also，somearecarnivorous，somegraminivorous，someomnivorous:

whilstsomefeedonapeculiardiet，asforinstancethebeesandthespiders，forthebeelivesonhoneyandcertainothersweets，andthespiderlivesbycatchingflies；andsomecreaturesliveonfish。Again，somecreaturescatchtheirfood，otherstreasureitup；

whereasothersdonotso。

Somecreaturesprovidethemselveswithadwelling，othersgowithoutone:oftheformerkindarethemole，themouse，theant，thebee；ofthelatterkindaremanyinsectsandquadrupeds。

Further，inrespecttolocalityofdwellingplace，somecreaturesdwellunderground，asthelizardandthesnake；othersliveonthesurfaceoftheground，asthehorseandthedog。maketothemselvesholes，othersdonotSomearenocturnal，astheowlandthebat；othersliveinthedaylight。

Moreover，somecreaturesaretameandsomearewild:someareatalltimestame，asmanandthemule；othersareatalltimessavage，astheleopardandthewolf；andsomecreaturescanberapidlytamed，astheelephant。

Again，wemayregardanimalsinanotherlight。For，wheneveraraceofanimalsisfounddomesticated，thesameisalwaystobefoundinawildcondition；aswefindtobethecasewithhorses，kine，swine，(men)，sheep，goats，anddogs。

Further，someanimalsemitsoundwhileothersaremute，andsomeareendowedwithvoice:oftheselattersomehavearticulatespeech，whileothersareinarticulate；somearegiventocontinualchirpingandtwitteringsomearepronetosilence；somearemusical，andsomeunmusical；butallanimalswithoutexceptionexercisetheirpowerofsingingorchatteringchieflyinconnexionwiththeintercourseofthesexes。

Again，somecreaturesliveinthefields，asthecushat；someonthemountains，asthehoopoe；somefrequenttheabodesofmen，asthepigeon。

Some，again，arepeculiarlysalacious，asthepartridge，thebarn-doorcockandtheircongeners；othersareinclinedtochastity，asthewholetribeofcrows，forbirdsofthiskindindulgebutrarelyinsexualintercourse。

Ofmarineanimals，again，someliveintheopenseas，someneartheshore，someonrocks。

Furthermore，somearecombativeunderoffence；othersareprovidentfordefence。Oftheformerkindaresuchasactasaggressorsuponothersorretaliatewhensubjectedtoillusage，andofthelatterkindaresuchasmerelyhavesomemeansofguardingthemselvesagainstattack。

Animalsalsodifferfromoneanotherinregardtocharacterinthefollowingrespects。Somearegood-tempered，sluggish，andlittlepronetoferocity，astheox；othersarequicktempered，ferociousandunteachable，asthewildboar；someareintelligentandtimid，asthestagandthehare；othersaremeanandtreacherous，asthesnake；othersarenobleandcourageousandhigh-bred，asthelion；

othersarethorough-bredandwildandtreacherous，asthewolf:for，bytheway，ananimalishighbredifitcomefromanoblestock，andananimalisthorough-bredifitdoesnotdeflectfromitsracialcharacteristics。

Further，somearecraftyandmischievous，asthefox；somearespiritedandaffectionateandfawning，asthedog；othersareeasy-temperedandeasilydomesticated，astheelephant；othersarecautiousandwatchful，asthegoose；othersarejealousandself-conceited，asthepeacock。Butofallanimalsmanaloneiscapableofdeliberation。

Manyanimalshavememory，andarecapableofinstruction；butnoothercreatureexceptmancanrecallthepastatwill。

Withregardtotheseveralgeneraofanimals，particularsastotheirhabitsoflifeandmodesofexistencewillbediscussedmorefullybyandby。

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Commontoallanimalsaretheorganswherebytheytakefoodandtheorganswhereintotheytakeit；andtheseareeitheridenticalwithoneanother，orarediverseinthewaysabovespecified:towit，eitheridenticalinform，orvaryinginrespectofexcessordefect，orresemblingoneanotheranalogically，ordifferinginposition。

Furthermore，thegreatmajorityofanimalshaveotherorgansbesidestheseincommon，wherebytheydischargetheresiduumoftheirfood:Isay，thegreatmajority，forthisstatementdoesnotapplytoall。And，bytheway，theorganwherebyfoodistakeniniscalledthemouth，andtheorganwhereintoitistaken，thebelly；

theremainderofthealimentarysystemhasagreatvarietyofnames。

Nowtheresiduumoffoodistwofoldinkind，wetanddry，andsuchcreaturesashaveorgansreceptiveofwetresiduumareinvariablyfoundwithorgansreceptiveofdryresiduum；butsuchashaveorgansreceptiveofdryresiduumneednotpossessorgansreceptiveofwetresiduum。Inotherwords，ananimalhasabowelorintestineifithaveabladder；butananimalmayhaveabowelandbewithoutabladder。And，bytheway，Imayhereremarkthattheorganreceptiveofwetresiduumistermed\'bladder\'，andtheorganreceptiveofdryresiduum\'intestineor\'bowel\'。

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Ofanimalsotherwise，agreatmanyhave，besidestheorgansabove-mentioned，anorganforexcretionofthesperm:andofanimalscapableofgenerationonesecretesintoanother，andtheotherintoitself。Thelatteristermed\'female\'，andtheformer\'male\'；butsomeanimalshaveneithermalenorfemale。Consequently，theorgansconnectedwiththisfunctiondifferinform，forsomeanimalshaveawombandothersanorgananalogousthereto。

Theabove-mentionedorgans，then，arethemostindispensablepartsofanimals；andwithsomeofthemallanimalswithoutexception，andwithothersanimalsforthemostpart，mustneedsbeprovided。

Onesense，andonealone，iscommontoallanimals-thesenseoftouch。Consequently，thereisnospecialnamefortheorganinwhichithasitsseat；forinsomegroupsofanimalstheorganisidentical，inothersitisonlyanalogous。

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Everyanimalissuppliedwithmoisture，and，iftheanimalbedeprivedofthesamebynaturalcausesorartificialmeans，deathensues:further，everyanimalhasanotherpartinwhichthemoistureiscontained。Thesepartsarebloodandvein，andinotheranimalsthereissomethingtocorrespond；butintheselatterthepartsareimperfect，beingmerelyfibreandserumorlymph。

Touchhasitsseatinapartuniformandhomogeneous，asinthefleshorsomethingofthekind，andgenerally，withanimalssuppliedwithblood，inthepartschargedwithblood。Inotheranimalsithasitsseatinpartsanalogoustothepartschargedwithblood；butinallcasesitisseatedinpartsthatintheirtexturearehomogeneous。

Theactivefaculties，onthecontrary，areseatedinthepartsthatareheterogeneous:as，forinstance，thebusinessofpreparingthefoodisseatedinthemouth，andtheofficeoflocomotioninthefeet，thewings，orinorganstocorrespond。

Again，someanimalsaresuppliedwithblood，asman，thehorse，andallsuchanimalsasare，whenfull-grown，eitherdestituteoffeet，ortwo-footed，orfour-footed；otheranimalsarebloodless，suchasthebeeandthewasp，and，ofmarineanimals，thecuttle-fish，thecrawfish，andallsuchanimalsashavemorethanfourfeet。

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Again，someanimalsareviviparous，othersoviparous，othersvermiparousor\'grub-bearing\'。Someareviviparous，suchasman，thehorse，theseal，andallotheranimalsthatarehair-coated，and，ofmarineanimals，thecetaceans，asthedolphin，andtheso-calledSelachia。(Oftheselatteranimals，somehaveatubularair-passageandnogills，asthedolphinandthewhale:thedolphinwiththeair-passagegoingthroughitsback，thewhalewiththeair-passageinitsforehead；othershaveuncoveredgills，astheSelachia，thesharksandrays。)

Whatwetermaneggisacertaincompletedresultofconceptionoutofwhichtheanimalthatistobedevelops，andinsuchawaythatinrespecttoitsprimitivegermitcomesfrompartonlyoftheegg，whiletherestservesforfoodasthegermdevelops。A\'grub\'ontheotherhandisathingoutofwhichinitsentiretytheanimalinitsentiretydevelops，bydifferentiationandgrowthoftheembryo。

Ofviviparousanimals，somehatcheggsintheirowninterior，ascreaturesofthesharkkind；othersengenderintheirinterioralivefoetus，asmanandthehorse。Whentheresultofconceptionisperfected，withsomeanimalsalivingcreatureisbroughtforth，withothersaneggisbroughttolight，withothersagrub。Oftheeggs，somehaveegg-shellsandareoftwodifferentcolourswithin，suchasbirds\'eggs；othersaresoft-skinnedandofuniformcolour，astheeggsofanimalsofthesharkkind。Ofthegrubs，somearefromthefirstcapableofmovement，othersaremotionless。However，withregardtothesephenomenaweshallspeakpreciselyhereafterwhenwecometotreatofGeneration。

Furthermore，someanimalshavefeetandsomearedestitutethereof。Ofsuchashavefeetsomeanimalshavetwo，asisthecasewithmenandbirds，andwithmenandbirdsonly；somehavefour，asthelizardandthedog；somehavemore，asthecentipedeandthebee；butallsoeverthathavefeethaveanevennumberofthem。

Ofswimmingcreaturesthataredestituteoffeet，somehavewingletsorfins，asfishes:andofthesesomehavefourfins，twoaboveontheback，twobelowonthebelly，asthegiltheadandthebasse；somehavetwoonly，-towit，suchasareexceedinglylongandsmooth，astheeelandtheconger；somehavenoneatall，asthemuraena，butusetheseajustassnakesusedryground-andbytheway，snakesswiminwaterinjustthesameway。Oftheshark-kindsomehavenofins，suchasthosethatareflatandlong-tailed，astherayandthesting-ray，butthesefishesswimactuallybytheundulatorymotionoftheirflatbodies；thefishingfrog，however，hasfins，andsolikewisehaveallsuchfishesashavenottheirflatsurfacesthinnedofftoasharpedge。

Ofthoseswimmingcreaturesthatappeartohavefeet，asisthecasewiththemolluscs，thesecreaturesswimbytheaidoftheirfeetandtheirfinsaswell，andtheyswimmostrapidlybackwardsinthedirectionofthetrunk，asisthecasewiththecuttle-fishorsepiaandthecalamary；and，bytheway，neitheroftheselattercanwalkasthepoulpeoroctopuscan。

Thehard-skinnedorcrustaceousanimals，likethecrawfish，swimbytheinstrumentalityoftheirtail-parts；andtheyswimmostrapidlytailforemost，bytheaidofthefinsdevelopeduponthatmember。Thenewtswimsbymeansofitsfeetandtail；anditstailresemblesthatofthesheatfish，tocomparelittlewithgreat。

Ofanimalsthatcanflysomearefurnishedwithfeatheredwings，astheeagleandthehawk；somearefurnishedwithmembranouswings，asthebeeandthecockchafer；othersarefurnishedwithleathernwings，astheflyingfoxandthebat。Allflyingcreaturespossessedofbloodhavefeatheredwingsorleathernwings；thebloodlesscreatureshavemembranouswings，asinsects。Thecreaturesthathavefeatheredwingsorleathernwingshaveeithertwofeetornofeetatall:fortherearesaidtobecertainflyingserpentsinEthiopiathataredestituteoffeet。

Creaturesthathavefeatheredwingsareclassedasagenusunderthenameof\'bird\'；theothertwogenera，theleathern-wingedandmembrane-winged，areasyetwithoutagenerictitle。

Ofcreaturesthatcanflyandarebloodlesssomearecoleopterousorsheath-winged，fortheyhavetheirwingsinasheathorshard，likethecockchaferandthedung-beetle；othersaresheathless，andoftheselattersomearedipterousandsometetrapterous:tetrapterous，suchasarecomparativelylargeorhavetheirstingsinthetail，dipterous，suchasarecomparativelysmallorhavetheirstingsinfront。Thecoleopteraare，withoutexception，devoidofstings；thedipterahavethestinginfront，asthefly，thehorsefly，thegadfly，andthegnat。

Bloodlessanimalsasageneralruleareinferiorinpointofsizetobloodedanimals；though，bytheway，therearefoundintheseasomefewbloodlesscreaturesofabnormalsize，asinthecaseofcertainmolluscs。Andofthesebloodlessgenera，thosearethelargestthatdwellinmilderclimates，andthosethatinhabittheseaarelargerthanthoselivingondrylandorinfreshwater。

Allcreaturesthatarecapableofmotionmovewithfourormorepointsofmotion；thebloodedanimalswithfouronly:as，forinstance，manwithtwohandsandtwofeet，birdswithtwowingsandtwofeet，quadrupedsandfishesseverallywithfourfeetandfourfins。Creaturesthathavetwowingletsorfins，orthathavenoneatalllikeserpents，moveallthesamewithnotlessthanfourpointsofmotion；fortherearefourbendsintheirbodiesastheymove，ortwobendstogetherwiththeirfins。Bloodlessandmanyfootedanimals，whetherfurnishedwithwingsorfeet，movewithmorethanfourpointsofmotion；as，forinstance，thedayflymoveswithfourfeetandfourwings:and，Imayobserveinpassing，thiscreatureisexceptionalnotonlyinregardtothedurationofitsexistence，whenceitreceivesitsname，butalsobecausethoughaquadrupedithaswingsalso。

Allanimalsmovealike，four-footedandmany-footed；inotherwords，theyallmovecross-corner-wise。Andanimalsingeneralhavetwofeetinadvance；thecrabalonehasfour。

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Veryextensivegeneraofanimals，intowhichothersubdivisionsfall，arethefollowing:one，ofbirds；one，offishes；andanother，ofcetaceans。Nowallthesecreaturesareblooded。

Thereisanothergenusofthehard-shellkind，whichiscalledoyster；anotherofthesoft-shellkind，notasyetdesignatedbyasingleterm，suchasthespinycrawfishandthevariouskindsofcrabsandlobsters；andanotherofmolluscs，asthetwokindsofcalamaryandthecuttle-fish；thatofinsectsisdifferent。Alltheselattercreaturesarebloodless，andsuchofthemashavefeethaveagoodlynumberofthem；andoftheinsectssomehavewingsaswellasfeet。

Oftheotheranimalsthegeneraarenotextensive。Forinthemonespeciesdoesnotcomprehendmanyspecies；butinonecase，asman，thespeciesissimple，admittingofnodifferentiation，whileothercasesadmitofdifferentiation，buttheformslackparticulardesignations。

So，forinstance，creaturesthatarequdapedalandunprovidedwithwingsarebloodedwithoutexception，butsomeofthemareviviparous，andsomeoviparous。Suchasareviviparousarehair-coated，andsuchasareoviparousarecoveredwithakindoftessellatedhardsubstance；andthetessellatedbitsofthissubstanceare，asitwere，similarinregardtopositiontoascale。

Ananimalthatisbloodedandcapableofmovementondryland，butisnaturallyunprovidedwithfeet，belongstotheserpentgenus；

andanimalsofthisgenusarecoatedwiththetessellatedhornysubstance。Serpentsingeneralareoviparous；theadder，anexceptionalcase，isviviparous:fornotallviviparousanimalsarehair-coated，andsomefishesalsoareviviparous。

Allanimals，however，thatarehair-coatedareviviparous。For，bytheway，onemustregardasakindofhairsuchpricklyhairsashedgehogsandporcupinescarry；forthesespinesperformtheofficeofhair，andnotoffeetasisthecasewithsimilarpartsofsea-urchins。

Inthegenusthatcombinesallviviparousquadrupedsaremanyspecies，butundernocommonappellation。Theyareonlynamedasitwereonebyone，aswesayman，lion，stag，horse，dog，andsoon；

though，bytheway，thereisasortofgenusthatembracesallcreaturesthathavebushymanesandbushytails，suchasthehorse，theass，themule，thejennet，andtheanimalsthatarecalledHemioniinSyria，-fromtheirexternallyresemblingmules，thoughtheyarenotstrictlyofthesamespecies。Andthattheyarenotsoisprovedbythefactthattheymatewithandbreedfromoneanother。Forallthesereasons，wemusttakeanimalsspeciesbyspecies，anddiscusstheirpeculiaritiesseverally\'

Theseprecedingstatements，then，havebeenputforwardthusinageneralway，asakindofforetasteofthenumberofsubjectsandofthepropertiesthatwehavetoconsiderinorderthatwemayfirstgetaclearnotionofdistinctivecharacterandcommonproperties。Byandbyweshalldiscussthesematterswithgreaterminuteness。

Afterthisweshallpassontothediscussionofcauses。Fortodothiswhentheinvestigationofthedetailsiscompleteistheproperandnaturalmethod，andthatwherebythesubjectsandthepremissesofourargumentwillafterwardsberenderedplain。

Inthefirstplacewemustlooktotheconstituentpartsofanimals。Foritisinawayrelativetotheseparts，firstandforemost，thatanimalsintheirentiretydifferfromoneanother:

eitherinthefactthatsomehavethisorthat，whiletheyhavenotthatorthis；orbypeculiaritiesofpositionorofarrangement；orbythedifferencesthathavebeenpreviouslymentioned，dependingupondiversityofform，orexcessordefectinthisorthatparticular，onanalogy，oroncontrastsoftheaccidentalqualities。

Tobeginwith，wemusttakeintoconsiderationthepartsofMan。For，justaseachnationiswonttoreckonbythatmonetarystandardwithwhichitismostfamiliar，somustwedoinothermatters。And，ofcourse，manistheanimalwithwhichweareallofusthemostfamiliar。

Nowthepartsareobviousenoughtophysicalperception。However，withtheviewofobservingdueorderandsequenceandofcombiningrationalnotionswithphysicalperception，weshallproceedtoenumeratetheparts:firstly，theorganic，andafterwardsthesimpleornon-composite。

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Thechiefpartsintowhichthebodyasawholeissubdivided，arethehead，theneck，thetrunk(extendingfromthenecktotheprivyparts)，whichiscalledthethorax，twoarmsandtwolegs。

Ofthepartsofwhichtheheadiscomposedthehair-coveredportioniscalledthe\'skull\'。Thefrontportionofitistermed\'bregma\'or\'sinciput\'，developedafterbirth-foritisthelastofallthebonesinthebodytoacquiresolidity，-thehinderpartistermedthe\'occiput\'，andthepartinterveningbetweenthesinciputandtheocciputisthe\'crown\'。Thebrainliesunderneaththesinciput；theocciputishollow。Theskullconsistsentirelyofthinbone，roundedinshape，andcontainedwithinawrapperoffleshlessskin。

Theskullhassutures:one，ofcircularform，inthecaseofwomen；inthecaseofmen，asageneralrule，threemeetingatapoint。Instanceshavebeenknownofaman\'sskulldevoidofsuturealtogether。Intheskullthemiddleline，wherethehairparts，iscalledthecrownorvertex。Insomecasesthepartingisdouble；

thatistosay，somemenaredoublecrowned，notinregardtothebonyskull，butinconsequenceofthedoublefallorsetofthehair。

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Thepartthatliesundertheskulliscalledthe\'face\':butinthecaseofmanonly，forthetermisnotappliedtoafishortoanox。Inthefacethepartbelowthesinciputandbetweentheeyesistermedtheforehead。Whenmenhavelargeforeheads，theyareslowtomove；whentheyhavesmallones，theyarefickle；whentheyhavebroadones，theyareapttobedistraught；whentheyhaveforeheadsroundedorbulgingout，theyarequick-tempered。

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Underneaththeforeheadaretwoeyebrows。Straighteyebrowsareasignofsoftnessofdisposition；suchascurveintowardsthenose，ofharshness；suchascurveouttowardsthetemples，ofhumouranddissimulation；suchasaredrawnintowardsoneanother，ofjealousy。

Undertheeyebrowscometheeyes。Thesearenaturallytwoinnumber。Eachofthemhasanupperandalowereyelid，andthehairsontheedgesofthesearetermed\'eyelashes\'。Thecentralpartoftheeyeincludesthemoistpartwherebyvisioniseffected，termedthe\'pupil\'，andthepartsurroundingitcalledthe\'black\'；thepartoutsidethisisthe\'white\'。Apartcommontotheupperandlowereyelidisapairofnicksorcorners，oneinthedirectionofthenose，andtheotherinthedirectionofthetemples。Whenthesearelongtheyareasignofbaddisposition；ifthesidetowardthenostrilbefleshyandcomb-like，theyareasignofdishonesty。

Allanimals，asageneralrule，areprovidedwitheyes，exceptingtheostracodermsandotherimperfectcreatures；atallevents，allviviparousanimalshaveeyes，withtheexceptionofthemole。Andyetonemightassertthat，thoughthemolehasnoteyesinthefullsense，yetithaseyesinakindofaway。Forinpointofabsolutefactitcannotsee，andhasnoeyesvisibleexternally；butwhentheouterskinisremoved，itisfoundtohavetheplacewhereeyesareusuallysituated，andtheblackpartsoftheeyesrightlysituated，andalltheplacethatisusuallydevotedontheoutsidetoeyes:

showingthatthepartsarestuntedindevelopment，andtheskinallowedtogrowover。

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Oftheeyethewhiteisprettymuchthesameinallcreatures；butwhatiscalledtheblackdiffersinvariousanimals。Somehavetherimblack，somedistinctlyblue，somegreyish-blue，somegreenish；andthislastcolouristhesignofanexcellentdisposition，andisparticularlywelladaptedforsharpnessofvision。Manistheonly，ornearlytheonly，creature，thathaseyesofdiversecolours。

Animals，asarule，haveeyesofonecolouronly。Somehorseshaveblueeyes。

Ofeyes，somearelarge，somesmall，somemedium-sized；ofthese，themedium-sizedarethebest。Moreover，eyessometimesprotrude，sometimesrecede，sometimesareneitherprotrudingnorreceding。Ofthese，therecedingeyeisinallanimalsthemostacute；butthelastkindarethesignofthebestdisposition。Again，eyesaresometimesinclinedtowinkunderobservation，sometimestoremainopenandstaring，andsometimesaredisposedneithertowinknorstare。Thelastkindarethesignofthebestnature，andoftheothers，thelatterkindindicatesimpudence，andtheformerindecision。

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Furthermore，thereisaportionofthehead，wherebyananimalhears，apartincapableofbreathing，the\'ear\'。Isay\'incapableofbreathing\'，forAlcmaeonismistakenwhenhesaysthatgoatsinspirethroughtheirears。Oftheearonepartisunnamed，theotherpartiscalledthe\'lobe\'；anditisentirelycomposedofgristleandflesh。Theearisconstructedinternallylikethetrumpet-shell，andtheinnermostboneisliketheearitself，andintoitattheendthesoundmakesitsway，asintothebottomofajar。Thisreceptacledoesnotcommunicatebyanypassagewiththebrain，butdoessowiththepalate，andaveinextendsfromthebraintowardsit。

Theeyesalsoareconnectedwiththebrain，andeachofthemliesattheendofalittlevein。Ofanimalspossessedofearsmanistheonlyonethatcannotmovethisorgan。Ofcreaturespossessedofhearing，somehaveears，whilstothershavenone，butmerelyhavethepassagesforearsvisible，as，forexample，featheredanimalsoranimalscoatedwithhornytessellates。

Viviparousanimals，withtheexceptionoftheseal，thedolphin，andthoseotherswhichafterasimilarfashiontothesearecetaceans，areallprovidedwithears；for，bytheway，theshark-kindarealsoviviparous。Now，thesealhasthepassagesvisiblewherebyithears；

butthedolphincanhear，buthasnoears，noryetanypassagesvisible。Butmanaloneisunabletomovehisears，andallotheranimalscanmovethem。Andtheearslie，withman，inthesamehorizontalplanewiththeeyes，andnotinaplaneabovethemasisthecasewithsomequadrupeds。Ofears，somearefine，somearecoarse，andsomeareofmediumtexture；thelastkindarebestforhearing，buttheyserveinnowaytoindicatecharacter。Someearsarelarge，somesmall，somemedium-sized；again，somestandoutfar，somelieincloseandtight，andsometakeupamediumposition；ofthesesuchasareofmediumsizeandofmediumpositionareindicationsofthebestdisposition，whilethelargeandoutstandingonesindicateatendencytoirrelevanttalkorchattering。Thepartinterceptedbetweentheeye，theear，andthecrownistermedthe\'temple\'。Again，thereisapartofthecountenancethatservesasapassageforthebreath，the\'nose\'。Foramaninhalesandexhalesbythisorgan，andsneezingiseffectedbyitsmeans:whichlastisanoutwardrushofcollectedbreath，andistheonlymodeofbreathusedasanomenandregardedassupernatural。Bothinhalationandexhalationgorightonfromthenosetowardsthechest；andwiththenostrilsaloneandseparatelyitisimpossibletoinhaleorexhale，owingtothefactthattheinspirationandrespirationtakeplacefromthechestalongthewindpipe，andnotbyanyportionconnectedwiththehead；andindeeditispossibleforacreaturetolivewithoutusingthisprocessofnasalrespiration。

Again，smellingtakesplacebymeansofthenose，-smelling，orthesensiblediscriminationofodour。Andthenostriladmitsofeasymotion，andisnot，liketheear，intrinsicallyimmovable。Apartofit，composedofgristle，constitutes，aseptumorpartition，andpartisanopenpassage；forthenostrilconsistsoftwoseparatechannels。Thenostril(ornose)oftheelephantislongandstrong，andtheanimalusesitlikeahand；forbymeansofthisorganitdrawsobjectstowardsit，andtakesholdofthem，andintroducesitsfoodintoitsmouth，whetherliquidordryfood，anditistheonlylivingcreaturethatdoesso。

Furthermore，therearetwojaws；thefrontpartofthemconstitutesthechin，andthehinderpartthecheek。Allanimalsmovethelowerjaw，withtheexceptionoftherivercrocodile；thiscreaturemovestheupperjawonly。

Nextafterthenosecometwolips，composedofflesh，andfacileofmotion。Themouthliesinsidethejawsandlips。Partsofthemoutharetherooforpalateandthepharynx。

Thepartthatissensibleoftasteisthetongue。Thesensationhasitsseatatthetipofthetongue；iftheobjecttobetastedbeplacedontheflatsurfaceoftheorgan，thetasteislesssensiblyexperienced。Thetongueissensitiveinallotherwayswhereinfleshingeneralisso:thatis，itcanappreciatehardness，orwarmthandcold，inanypartofit，justasitcanappreciatetaste。Thetongueissometimesbroad，sometimesnarrow，andsometimesofmediumwidth；

thelastkindisthebestandtheclearestinitsdiscriminationoftaste。Moreover，thetongueissometimeslooselyhung，andsometimesfastened:asinthecaseofthosewhomumbleandwholisp。

Thetongueconsistsofflesh，softandspongy，andtheso-called\'epiglottis\'isapartofthisorgan。

Thatpartofthemouththatsplitsintotwobitsiscalledthe\'tonsils\'；thatpartthatsplitsintomanybits，the\'gums\'。Boththetonsilsandthegumsarecomposedofflesh。Inthegumsareteeth，composedofbone。

Insidethemouthisanotherpart，shapedlikeabunchofgrapes，apillarstreakedwithveins。Ifthispillargetsrelaxedandinflameditiscalled\'uvula\'or\'bunchofgrapes\'，anditthenhasatendencytobringaboutsuffocation。

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Theneckisthepartbetweenthefaceandthetrunk。OfthisthefrontpartisthelarynxlandthebackparttheurThefrontpart，composedofgristle，throughwhichrespirationandspeechiseffected，istermedthe\'windpipe\'；thepartthatisfleshyistheoesophagus，insidejustinfrontofthechine。Theparttothebackoftheneckistheepomis，or\'shoulder-point\'。

Thesethenarethepartstobemetwithbeforeyoucometothethorax。

Tothetrunkthereisafrontpartandabackpart。Nextaftertheneckinthefrontpartisthechest，withapairofbreasts。Toeachofthebreastsisattachedateatornipple，throughwhichinthecaseoffemalesthemilkpercolates；andthebreastisofaspongytexture。Milk，bytheway，isfoundattimesinthemale；butwiththemalethefleshofthebreastistough，withthefemaleitissoftandporous。

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Nextafterthethoraxandinfrontcomesthe\'belly\'，anditsrootthe\'navel\'。Underneaththisrootthebilateralpartisthe\'flank\':

theundividedpartbelowthenavel，the\'abdomen\'，theextremityofwhichistheregionofthe\'pubes\'；abovethenavelthe\'hypochondrium\'；thecavitycommontothehypochondriumandtheflankisthegut-cavity。

Servingasabracegirdletothehinderpartsisthepelvis，andhenceitgetsitsname(osphus)，foritissymmetrical(isophues)inappearance；ofthefundamentthepartforrestingonistermedthe\'rump\'，andthepartwhereonthethighpivotsistermedthe\'socket\'(oracetabulum)。

The\'womb\'isapartpeculiartothefemale；andthe\'penis\'ispeculiartothemale。Thislatterorganisexternalandsituatedattheextremityofthetrunk；itiscomposedoftwoseparateparts:ofwhichtheextremepartisfleshy，doesnotalterinsize，andiscalledtheglans；androundaboutitisaskindevoidofanyspecifictitle，whichintegumentifitbecutasundernevergrowstogetheragain，anymorethandoesthejawortheeyelid。Andtheconnexionbetweenthelatterandtheglansiscalledthefrenum。Theremainingpartofthepenisiscomposedofgristle；itiseasilysusceptibleofenlargement；anditprotrudesandrecedesinthereversedirectionstowhatisobservableintheidenticalorganincats。Underneaththepenisaretwo\'testicles\'，andtheintegumentoftheseisaskinthatistermedthe\'scrotum\'。

Testiclesarenotidenticalwithflesh，andarenotaltogetherdiversefromit。Butbyandbyweshalltreatinanexhaustivewayregardingallsuchparts。

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Theprivypartofthefemaleisincharacteroppositetothatofthemale。Inotherwords，thepartunderthepubesisholloworreceding，andnot，likethemaleorgan，protruding。Further，thereisan\'urethra\'outsidethewomb；whichorganservesasapassageforthespermofthemale，andasanoutletforliquidexcretiontobothsexes)。

Thepartcommontotheneckandchestisthe\'throat\'；the\'armpit\'iscommontoside，arm，andshoulder；andthe\'groin\'iscommontothighandabdomen。Thepartinsidethethighandbuttocksisthe\'perineum\'，andthepartoutsidethethighandbuttocksisthe\'hypoglutis\'。

Thefrontpartsofthetrunkhavenowbeenenumerated。

Thepartbehindthechestistermedthe\'back\'。

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Partsofthebackareapairof\'shoulderblades\'，the\'back-bone\'，and，underneathonalevelwiththebellyinthetrunk，the\'loins\'。Commontotheupperandlowerpartofthetrunkarethe\'ribs\'，eightoneitherside，forastotheso-calledseven-ribbedLigyanswehavenotreceivedanytrustworthyevidence。

Man，then，hasanupperandalowerpart，afrontandabackpart，arightandaleftside。Nowtherightandtheleftsideareprettywellalikeintheirpartsandidenticalthroughout，exceptthattheleftsideistheweakerofthetwo；butthebackpartsdonotresemblethefrontones，neitherdotheloweronestheupper:onlythattheseupperandlowerpartsmaybesaidtoresembleoneanotherthusfar，that，ifthefacebeplumpormeagre，theabdomenisplumpormeagretocorrespond；andthatthelegscorrespondtothearms，andwheretheupperarmisshortthethighisusuallyshortalso，andwherethefeetaresmallthehandsaresmallcorrespondingly。

Ofthelimbs，oneset，formingapair，is\'arms\'。Tothearmbelongthe\'shoulder\'，\'upper-arm\'，\'elbow\'，\'fore-arm\'，and\'hand\'。

Tothehandbelongthe\'palm\'，andthefive\'fingers\'。Thepartofthefingerthatbendsistermed\'knuckle\'，thepartthatisinflexibleistermedthe\'phalanx\'。Thebigfingerorthumbissingle-jointed，theotherfingersaredoublejointed。Thebendingbothofthearmandofthefingertakesplacefromwithoutinwardsinallcases；andthearmbendsattheelbow。Theinnerpartofthehandistermedthepalm\'，andisfleshyanddividedbyjointsorlines:inthecaseoflong-livedpeoplebyoneortwoextendingrightacross，inthecaseoftheshort-livedbytwo，notsoextending。Thejointbetweenhandandarmistermedthe\'wrist\'。Theoutsideorbackofthehandissinewy，andhasnospecificdesignation。

Thereisanotherduplicatelimb，the\'leg\'。Ofthislimbthedouble-knobbedpartistermedthe\'thigh-bone\'，theslidingpartofthe\'kneecap\'，thedouble-bonedpartthe\'leg\'；thefrontpartofthislatteristermedthe\'shin\'，andthepartbehinditthe\'calf\'，whereinthefleshissinewyandvenous，insomecasesdrawnupwardstowardsthehollowbehindtheknee，asinthecaseofpeoplewithlargehips，andinothercasesdrawndownwards。Thelowerextremityoftheshinisthe\'ankle\'，duplicateineitherleg。Thepartofthelimbthatcontainsamultiplicityofbonesisthe\'foot\'。Thehinderpartofthefootisthe\'heel\'；atthefrontofitthedividedpartconsistsof\'toes\'，fiveinnumber；thefleshypartunderneathisthe\'ball\'；theupperpartorbackofthefootissinewyandhasnoparticularappellation；ofthetoe，oneportionisthe\'nail\'andanotherthe\'joint\'，andthenailisinallcasesattheextremity；

andtoesarewithoutexceptionsinglejointed。Menthathavetheinsideorsoleofthefootclumsyandnotarched，thatis，thatwalkrestingontheentireunder-surfaceoftheirfeet，arepronetoroguery。Thejointcommontothighandshinisthe\'knee\'。

These，then，arethepartscommontothemaleandthefemalesex。

Therelativepositionofthepartsastoupanddown，ortofrontandback，ortorightandleft，allthisasregardsexternalsmightsafelybelefttomereordinaryperception。Butforallthat，wemusttreatofthemforthesamereasonastheonepreviouslybroughtforward；thatistosay，wemustrefertotheminorderthatadueandregularsequencemaybeobservedinourexposition，andinorderthatbytheenumerationoftheseobviousfactsdueattentionmaybesubsequentlygiventothosepartsinmenandotheranimalsthatarediverseinanywayfromoneanother。

Inman，aboveallotheranimals，theterms\'upper\'and\'lower\'

areusedinharmonywiththeirnaturalpositions；forinhim，upperandlowerhavethesamemeaningaswhentheyareappliedtotheuniverseasawhole。Inlikemannertheterms，\'infront\'，\'behind\'，\'right\'and\'left\'，areusedinaccordancewiththeirnaturalsense。

Butinregardtootheranimals，insomecasesthesedistinctionsdonotexist，andinotherstheydoso，butinavagueway。Forinstance，theheadwithallanimalsisupandaboveinrespecttotheirbodies；butmanalone，ashasbeensaid，has，inmaturity，thispartuppermostinrespecttothematerialuniverse。

Nextaftertheheadcomestheneck，andthenthechestandtheback:theoneinfrontandtheotherbehind。Nextafterthesecomethebelly，theloins，thesexualparts，andthehaunches；thenthethighandshin；and，lastly，thefeet。

Thelegsbendfrontwards，inthedirectionofactualprogression，andfrontwardsalsoliesthatpartofthefootwhichisthemosteffectiveofmotion，andtheflexureofthatpart；buttheheelliesattheback，andtheankleboneslielaterally，earwise。Thearmsaresituatedtorightandleft，andbendinwards:sothattheconvexitiesformedbybentarmsandlegsarepracticallyfacetofacewithoneanotherinthecaseofman。

Asforthesensesandfortheorgansofsensation，theeyes，thenostrils，andthetongue，allalikearesituatedfrontwards；thesenseofhearing，andtheorganofhearing，theear，issituatedsideways，onthesamehorizontalplanewiththeeyes。Theeyesinmanare，inproportiontohissize，nearertooneanotherthaninanyotheranimal。

Ofthesensesmanhasthesenseoftouchmorerefinedthananyanimal，andsoalso，butinlessdegree，thesenseoftaste；inthedevelopmentoftheothersensesheissurpassedbyagreatnumberofanimals。

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Theparts，then，thatareexternallyvisiblearearrangedinthewayabovestated，andasarulehavetheirspecialdesignations，andfromuseandwontareknownfamiliarlytoall；butthisisnotthecasewiththeinnerparts。Forthefactisthattheinnerpartsofmanaretoaverygreatextentunknown，andtheconsequenceisthatwemusthaverecoursetoanexaminationoftheinnerpartsofotheranimalswhosenatureinanywayresemblesthatofman。

Inthefirstplacethen，thebrainliesinthefrontpartofthehead。Andthisholdsalikewithallanimalspossessedofabrain；

andallbloodedanimalsarepossessedthereof，and，bytheway，molluscsaswell。But，takingsizeforsizeofanimal，thelargestbrain，andthemoistest，isthatofman。Twomembranesencloseit:thestrongeroneneartheboneoftheskull；theinnerone，roundthebrainitself，isfiner。Thebraininallcasesisbilateral。Behindthis，rightattheback，comeswhatistermedthe\'cerebellum\'，differinginformfromthebrainaswemaybothfeelandsee。

Thebackoftheheadiswithallanimalsemptyandhollow，whateverbeitssizeinthedifferentanimals。Forsomecreatureshavebigheadswhilethefacebelowissmallinproportion，asisthecasewithround-facedanimals；somehavelittleheadsandlongjaws，asisthecase，withoutexception，amonganimalsofthemane-and-tailspecies。

Thebraininallanimalsisbloodless，devoidofveins，andnaturallycoldtothetouch；inthegreatmajorityofanimalsithasasmallhollowinitscentre。Thebrain-caularounditisreticulatedwithveins；andthisbrain-caulisthatskin-likemembranewhichcloselysurroundsthebrain。Abovethebrainisthethinnestandweakestboneofthehead，whichistermedor\'sinciput\'。

Fromtheeyetheregothreeductstothebrain:thelargestandthemedium-sizedtothecerebellum，theleasttothebrainitself；andtheleastistheonesituatednearesttothenostril。Thetwolargestones，then，runsidebysideanddonotmeet；themedium-sizedonesmeet-andthisisparticularlyvisibleinfishes，-fortheylienearerthanthelargeonestothebrain；thesmallestpairarethemostwidelyseparatefromoneanother，anddonotmeet。

Insidetheneckiswhatistermedtheoesophagus(whoseothernameisderivedoesophagusfromitslengthandnarrowness)，andthewindpipe。Thewindpipeissituatedinfrontoftheoesophagusinallanimalsthathaveawindpipe，andallanimalshaveonethatarefurnishedwithlungs。Thewindpipeismadeupofgristle，issparinglysuppliedwithblood，andisstreakedallroundwithnumerousminuteveins；itissituated，initsupperpart，nearthemouth，belowtheapertureformedbythenostrilsintothemouth-anaperturethroughwhich，whenmen，indrinking，inhaleanyoftheliquid，thisliquidfindsitswayoutthroughthenostrils。Inbetwixtthetwoopeningscomestheso-calledepiglottis，anorgancapableofbeingdrawnoverandcoveringtheorificeofthewindpipecommunicatingwiththemouth；

theendofthetongueisattachedtotheepiglottis。Intheotherdirectionthewindpipeextendstotheintervalbetweenthelungs，andhereuponbifurcatesintoeachofthetwodivisionsofthelung；

forthelunginallanimalspossessedoftheorganhasatendencytobedouble。Inviviparousanimals，however，theduplicationisnotsoplainlydiscernibleasinotherspecies，andtheduplicationisleastdiscernibleinman。Andinmantheorganisnotsplitintomanyparts，asisthecasewithsomevivipara，neitherisitsmooth，butitssurfaceisuneven。

Inthecaseoftheovipara，suchasbirdsandoviparousquadrupeds，thetwopartsoftheorganareseparatedtoadistancefromoneanother，sothatthecreaturesappeartobefurnishedwithapairoflungs；andfromthewindpipe，itselfsingle，therebranchofftwoseparatepartsextendingtoeachofthetwodivisionsofthelung。Itisattachedalsotothegreatveinandtowhatisdesignatedthe\'aorta\'。Whenthewindpipeischargedwithair，theairpassesontothehollowpartsofthelung。Thesepartshavedivisions，composedofgristle，whichmeetatanacuteangle；fromthedivisionsrunpassagesthroughtheentirelung，givingoffsmallerandsmallerramifications。Theheartalsoisattachedtothewindpipe，byconnexionsoffat，gristle，andsinew；andatthepointofjuncturethereisahollow。Whenthewindpipeischargedwithair，theentranceoftheairintotheheart，thoughimperceptibleinsomeanimals，isperceptibleenoughinthelargerones。Sucharethepropertiesofthewindpipe，andittakesinandthrowsoutaironly，andtakesinnothingelseeitherdryorliquid，orelseitcausesyoupainuntilyoushallhavecoughedupwhatevermayhavegonedown。

Theoesophaguscommunicatesatthetopwiththemouth，closetothewindpipe，andisattachedtothebackboneandthewindpipebymembranousligaments，andatlastfindsitswaythroughthemidriffintothebelly。Itiscomposedofflesh-likesubstance，andiselasticbothlengthwaysandbreadthways。

Thestomachofmanresemblesthatofadog；foritisnotmuchbiggerthanthebowel，butissomewhatlikeabowelofmorethanusualwidth；thencomesthebowel，single，convoluted，moderatelywide。

Thelowerpartofthegutislikethatofapig；foritisbroad，andthepartfromittothebuttocksisthickandshort。Thecaul，orgreatomentum，isattachedtothemiddleofthestomach，andconsistsofafattymembrane，asisthecasewithallotheranimalswhosestomachsaresingleandwhichhaveteethinbothjaws。

Themesenteryisoverthebowels；thisalsoismembranousandbroad，andturnstofat。Itisattachedtothegreatveinandtheaorta，andthererunthroughitanumberofveinscloselypackedtogether，extendingtowardstheregionofthebowels，beginningaboveandendingbelow。

Somuchforthepropertiesoftheoesophagus，thewindpipe，andthestomach。

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Thehearthasthreecavities，andissituatedabovethelungatthedivisionofthewindpipe，andisprovidedwithafattyandthickmembranewhereitfastensontothegreatveinandtheaorta。Itlieswithitstaperingportionupontheaorta，andthisportionissimilarlysituatedinrelationtothechestinallanimalsthathaveachest。Inallanimalsalike，inthosethathaveachestandinthosethathavenone，theapexoftheheartpointsforwards，althoughthisfactmightpossiblyescapenoticebyachangeofpositionunderdissection。Theroundedendoftheheartisatthetop。Theapexistoagreatextentfleshyandcloseintexture，andinthecavitiesoftheheartaresinews。Asaruletheheartissituatedinthemiddleofthechestinanimalsthathaveachest，andinmanitissituatedalittletotheleft-handside，leaningalittlewayfromthedivisionofthebreaststowardstheleftbreastintheupperpartofthechest。

Theheartisnotlarge，andinitsgeneralshapeitisnotelongated；infact，itissomewhatroundinform:only，beitremembered，itissharp-pointedatthebottom。Ithasthreecavities，ashasbeensaid:theright-handonethelargestofthethree，theleft-handonetheleast，andthemiddleoneintermediateinsize。Allthesecavities，eventhetwosmallones，areconnectedbypassageswiththelung，andthisfactisrenderedquiteplaininoneofthecavities。Andbelow，atthepointofattachment，inthelargestcavitythereisaconnexionwiththegreatvein(nearwhichthemesenterylies)；andinthemiddleonethereisaconnexionwiththeaorta。

Canalsleadfromtheheartintothelung，andbranchoffjustasthewindpipedoes，runningalloverthelungparallelwiththepassagesfromthewindpipe。Thecanalsfromtheheartareuppermost；

andthereisnocommonpassage，butthepassagesthroughtheirhavingacommonwallreceivethebreathandpassitontotheheart；

andoneofthepassagesconveysittotherightcavity，andtheothertotheleft。

Withregardtothegreatveinandtheaortaweshall，byandby，treatofthemtogetherinadiscussiondevotedtothemandtothemalone。Inallanimalsthatarefurnishedwithalung，andthatarebothinternallyandexternallyviviparous，thelungisofallorgansthemostrichlysuppliedwithblood；forthelungisthroughoutspongyintexture，andalongbyeverysingleporeinitgobranchesfromthegreatvein。Thosewhoimagineittobeemptyarealtogethermistaken；andtheyareledintotheirerrorbytheirobservationoflungsremovedfromanimalsunderdissection，outofwhichorgansthebloodhadallescapedimmediatelyafterdeath。

Oftheotherinternalorganstheheartalonecontainsblood。

Andthelunghasbloodnotinitselfbutinitsveins，butthehearthasbloodinitself；forineachofitsthreecavitiesithasblood，butthethinnestbloodiswhatithasinitscentralcavity。

Underthelungcomesthethoracicdiaphragmormidriff，attachedtotheribs，thehypochondriaandthebackbone，withathinmembraneinthemiddleofit。Ithasveinsrunningthroughit；andthediaphragminthecaseofmanisthickerinproportiontothesizeofhisframethaninotheranimals。

Underthediaphragmontheright-handsideliesthe\'liver\'，andontheleft-handsidethe\'spleen\'，alikeinallanimalsthatareprovidedwiththeseorgansinanordinaryandnotpreternaturalway；for，beitobserved，insomequadrupedstheseorganshavebeenfoundinatransposedposition。Theseorgansareconnectedwiththestomachbythecaul。

Tooutwardviewthespleenofmanisnarrowandlong，resemblingtheself-sameorganinthepig。Theliverinthegreatmajorityofanimalsisnotprovidedwitha\'gall-bladder\'；butthelatterispresentinsome。Theliverofamanisround-shaped，andresemblesthesameorganintheox。And，bytheway，theabsenceabovereferredtoofagall-bladderisattimesmetwithinthepracticeofaugury。Forinstance，inacertaindistrictoftheChalcidicsettlementinEuboeathesheeparedevoidofgall-bladders；andinNaxosnearlyallthequadrupedshaveonesolargethatforeignerswhentheyoffersacrificewithsuchvictimsarebewilderedwithfright，undertheimpressionthatthephenomenonisnotduetonaturalcauses，butbodessomemischieftotheindividualofferersofthesacrifice。

Again，theliverisattachedtothegreatvein，butithasnocommunicationwiththeaorta；fortheveinthatgoesofffromthegreatveingoesrightthroughtheliver，atapointwherearetheso-called\'portals\'oftheliver。Thespleenalsoisconnectedonlywiththegreatvein，foraveinextendstothespleenofffromit。

Aftertheseorganscomethe\'kidneys\'，andtheseareplacedclosetothebackbone，andresembleincharacterthesameorganinkine。

Inallanimalsthatareprovidedwiththisorgan，therightkidneyissituatedhigherupthantheother。Ithasalsolessfattysubstancethantheleft-handoneandislessmoist。Andthisphenomenonalsoisobservableinalltheotheranimalsalike。

Furthermore，passagesorductsleadintothekidneysbothfromthegreatveinandfromtheaorta，onlynotintothecavity。For，bytheway，thereisacavityinthemiddleofthekidney，biggerinsomecreaturesandlessinothers；butthereisnoneinthecaseoftheseal。Thislatteranimalhaskidneysresemblinginshapetheidenticalorganinkine，butinitscasetheorgansaremoresolidthaninanyotherknowncreature。Theductsthatleadintothekidneyslosethemselvesinthesubstanceofthekidneysthemselves；andtheproofthattheyextendnofartherrestsonthefactthattheycontainnoblood，norisanyclotfoundtherein。Thekidneys，however，have，ashasbeensaid，asmallcavity。Fromthiscavityinthekidneythereleadtwoconsiderableductsoruretersintothebladder；andothersspringfromtheaorta，strongandcontinuous。Andtothemiddleofeachofthetwokidneysisattachedahollowsinewyvein，stretchingrightalongthespinethroughthenarrows；byandbytheseveinsarelostineitherloin，andagainbecomevisibleextendingtotheflank。Andtheseoff-branchingsoftheveinsterminateinthebladder。

Forthebladderliesattheextremity，andisheldinpositionbytheductsstretchingfromthekidneys，alongthestalkthatextendstotheurethra；andprettywellallrounditisfastenedbyfinesinewymembranes，thatresembletosomeextentthethoracicdiaphragm。Thebladderinmanis，proportionatelytohissize，tolerablylarge。

Tothestalkofthebladdertheprivatepartisattached，theexternalorificescoalescing；butalittlelowerdown，oneoftheopeningscommunicateswiththetesticlesandtheotherwiththebladder。Thepenisisgristlyandsinewyinitstexture。Withitareconnectedthetesticlesinmaleanimals，andthepropertiesoftheseorgansweshalldiscussinourgeneralaccountofthesaidorgan。

Alltheseorgansaresimilarinthefemale；forthereisnodifferenceinregardtotheinternalorgans，exceptinrespecttothewomb，andwithreferencetotheappearanceofthisorganImustreferthereadertodiagramsinmy\'Anatomy\'。Thewomb，however，issituatedoverthebowel，andthebladderliesoverthewomb。Butwemusttreatbyandbyinourpagesofthewombofallfemaleanimalsviewedgenerally。Forthewombsofallfemaleanimalsarenotidentical，neitherdotheirlocaldispositionscoincide。

Thesearetheorgans，internalandexternal，ofman，andsuchistheirnatureandsuchtheirlocaldisposition。

BookII

1

Withregardtoanimalsingeneral，somepartsororgansarecommontoall，ashasbeensaid，andsomearecommononlytoparticulargenera；theparts，moreover，areidenticalwithordifferentfromoneanotheronthelinesalreadyrepeatedlylaiddown。Forasageneralruleallanimalsthataregenericallydistincthavethemajorityoftheirpartsororgansdifferentinformorspecies；andsomeofthemtheyhaveonlyanalogicallysimilaranddiverseinkindorgenus，whiletheyhaveothersthatarealikeinkindbutspecificallydiverse；andmanypartsororgansexistinsomeanimals，butnotinothers。

Forinstance，viviparousquadrupedshaveallaheadandaneck，andallthepartsororgansofthehead，buttheydiffereachfromotherintheshapesoftheparts。Thelionhasitsneckcomposedofonesingleboneinsteadofvertebrae；but，whendissected，theanimalisfoundinallinternalcharacterstoresemblethedog。

Thequadrupedalviviparainsteadofarmshaveforelegs。Thisistrueofallquadrupeds，butsuchofthemashavetoeshave，practicallyspeaking，organsanalogoustohands；atallevents，theyusethesefore-limbsformanypurposesashands。Andtheyhavethelimbsontheleft-handsidelessdistinctfromthoseontherightthanman。

Thefore-limbsthenservemoreorlessthepurposeofhandsinquadrupeds，withtheexceptionoftheelephant。Thislatteranimalhasitstoessomewhatindistinctlydefined，anditsfrontlegsaremuchbiggerthanitshinderones；itisfive-toed，andhasshortanklestoitshindfeet。Butithasanosesuchinpropertiesandsuchinsizeastoallowofitsusingthesameforahand。Foriteatsanddrinksbyliftingupitsfoodwiththeaidofthisorganintoitsmouth，andwiththesameorganitliftsuparticlestothedriveronitsback；withthisorganitcanpluckuptreesbytheroots，andwhenwalkingthroughwateritspoutsthewaterupbymeansofit；andthisorganiscapableofbeingcrookedorcoiledatthetip，butnotofflexinglikeajoint，foritiscomposedofgristle。

Ofallanimalsmanalonecanlearntomakeequaluseofbothhands。

Allanimalshaveapartanalogoustothechestinman，butnotsimilartohis；forthechestinmanisbroad，butthatofallotheranimalsisnarrow。Moreover，nootheranimalbutmanhasbreastsinfront；theelephant，certainly，hastwobreasts，nothoweverinthechest，butnearit。

Moreover，also，animalshavetheflexionsoftheirforeandhindlimbsindirectionsoppositetooneanother，andindirectionsthereverseofthoseobservedinthearmsandlegsofman；withtheexceptionoftheelephant。Inotherwords，withtheviviparousquadrupedsthefrontlegsbendforwardsandthehindonesbackwards，andtheconcavitiesofthetwopairsoflimbsthusfaceoneanother。

Theelephantdoesnotsleepstanding，assomewerewonttoassert，butitbendsitslegsandsettlesdown；onlythatinconsequenceofitsweightitcannotbenditslegonbothsidessimultaneously，butfallsintoarecumbentpositionononesideortheother，andinthispositionitgoestosleep。Anditbendsitshindlegsjustasamanbendshislegs。

Inthecaseoftheovipara，asthecrocodileandthelizardandthelike，bothpairsoflegs，foreandhind，bendforwards，withaslightswerveononeside。Theflexionissimilarinthecaseofthemultipeds；onlythatthelegsinbetweentheextremeendsalwaysmoveinamannerintermediatebetweenthatofthoseinfrontandthosebehind，andaccordinglybendsidewaysratherthanbackwardsorforwards。Butmanbendshisarmsandhislegstowardsthesamepoint，andthereforeinoppositeways:thatistosay，hebendshisarmsbackwards，withjustaslightinclinationinwards，andhislegsfrontwards。Noanimalbendsbothitsfore-limbsandhind-limbsbackwards；butinthecaseofallanimalstheflexionoftheshouldersisintheoppositedirectiontothatoftheelbowsorthejointsoftheforelegs，andtheflexureinthehipstothatofthekneesofthehind-legs:sothatsincemandiffersfromotheranimalsinflexion，thoseanimalsthatpossesssuchpartsasthesemovethemcontrariwisetoman。

Birdshavetheflexionsoftheirlimbslikethoseofthequadrupeds；for，althoughbipeds，theybendtheirlegsbackwards，andinsteadofarmsorfrontlegshavewingswhichbendfrontwards。

Thesealisakindofimperfectorcrippledquadruped；forjustbehindtheshoulder-bladeitsfrontfeetareplaced，resemblinghands，likethefrontpawsofthebear；fortheyarefurnishedwithfivetoes，andeachofthetoeshasthreeflexionsandanailofinconsiderablesize。Thehindfeetarealsofurnishedwithfivetoes；intheirflexionsandnailstheyresemblethefrontfeet，andinshapetheyresembleafish\'stail。