Butagentleandpeacefulanimalwhichlivesamongotheranimalsofthesamedispositionandofgentlenurture，willbeanenemyofbloodandcarnage；itwillblushinternallyathavingshedblood。Thereisperhapsthisdifference，thatsinceamonganimalseverythingissacrificedtotheirneeds，totheirpleasures，tothenecessitiesoflife，whichtheyenjoymorethanwe，theirremorseapparentlyshouldnotbeaskeenasours，becausewearenotinthesamestateofnecessityasthey。Customperhapsdullsandperhapsstiflesremorseaswellaspleasures。
　　ButIwillforamomentsupposethatIamutterlymistakeninconcludingthatalmostalltheworldholdsawrongopiniononthissubject，whileIaloneamright。Iwillgrantthatanimals，eventhebestofthem，donotknowthedifferencebetweenmoralgoodandevil，thattheyhavenorecollectionofthetroubletakenforthem，ofthekindnessdonethem，norealizationoftheirownvirtues。[Iwillsuppose]，forinstance，thatthislion，towhichI，likesomanyothers，havereferred，doesnotrememberatallthatitrefusedtokilltheman，abandonedtoitsfury，inacombatmoreinhumanthanonecouldfindamonglions，tigersandbears，puttogether。Forourcompatriotsfight，SwissagainstSwiss，brotheragainstbrother，recognizeeachother，andyetcaptureandkilleachotherwithoutremorse，becauseaprincepaysforthemurder。
　　Isupposeinshotthatthenaturallawhasnotbeengiventoanimals。Whatwillbetheconsequencesofthissupposition？Manisnotmouldedfromacostlierclay；naturehasusedbutonedough，andhasmerelyvariedtheleaven。ThereforeifanimalsdonotrepentforhavingviolatedthisinmostfeelingwhichI
　　amdiscussing，orratheriftheyabsolutelylackit，manmustnecessarilybeinthesamecondition。Farewellthentothenaturallawandallthefinetreatisespublishedaboutit！Thewholeanimalkingdomingeneralwouldbedeprivedofit。But，conversely，ifmancannotdispensewiththebeliefthatwhenhealthpermitshimtobehimself，healwaysdistinguishestheupright，humane，andvirtuous，fromthosewhoarenothuman，virtuous，norhonorable：
　　thatitiseasytotellvicefromvirtue，bytheuniquepleasureandthepeculiarrepugnancethatseemstobetheirnaturaleffects，itfollowsthatanimals，composedofthesamematter，lackingperhapsonlyonedegreeoffermentationtomakeitexactlylikeman’s，mustsharethesameprerogativesofanimalnature，andthatthusthereexistsnosoulorsensitivesubstancewithoutremorse。Thefollowingconsiderationswillreinforcetheseobservations。
　　Itisimpossibletodestroythenaturallaw。Theimpressofitonallanimalsissostrong，thatIhavenodoubtthatthewildestandmostsavagehavesomemomentsofrepentance。IbelievethatthatcruelmaidofChalonsinChampagnemusthavesorrowedforhercrime，ifshereallyatehersister。Ithinkthatthesamthingistrueofallthosewhocommitcrimes，eveninvoluntaryortemperamentalcrimes：trueofGastonofOrleanswhocouldnothelpstealing；ofacertainwomanwhowassubjecttothesamecrimewhenpregnant，andwhosechildreninheritedit；ofthewomanwho，inthesamecondition，ateherhusband；ofthatotherwomenwhokilledherchildren，saltedtheirbodies，andateapieceofthemeveryday，asalittlerelish；ofthatdaughterofathiefandcannibalwhoattwelveyearsfollowedinhissteps，althoughshehadbeenorphanedwhenshewasayearold，andhadbeenbroughtupbyhonestpeople；tosaynothingofmanyotherexamplesofwhichtherecordsofourobserversarefull，allofthemprovingthatthereareathousandhereditaryvicesandvirtueswhicharetransmittedfromparentstochildrenasthoseofthefostermotherpasstothechildrenshenurses。Now，Ibelieveandadmitthatthesewretchesdonotforthemostpartfeelatthetimetheenormityoftheiractions。Bulimia，orcaninehunger，forexample，canstifleallfeeling；itisamaniaofthestomachthatoneiscompelledtosatisfy，butwhatremorsemustbeinstoreforthosewomen，whenthecometothemselvesandgrowsober，andrememberthecrimestheyhavecommittedagainstthosetheyheldmostdear！Whatapunishmentforaninvoluntarycrimewhichtheycouldnotresist，ofwhichtheyhadnoconsciousnesswhatever！However，thisisapparentlynotenoughforthejudges。Forofthesewomen，ofwhomItell，onewascruellybeatenandburned，andanotherwasburiedalive。Irealizethatallthisisdemandedbytheinterestofsociety。Butdoubtlessitismuchtobewishedthatexcellentphysiciansmightbetheonlyjudges。Theyalonecouldtelltheinnocentcriminalfromtheguilty。
　　Ifreasonistheslaveofadepravedormaddesire，howcanitcontrolthedesire？
　　Butifcrimecarrieswithititsownmoreorlesscruelpunishment，ifthemostcontinuedandmostbarbaroushabitcannotentirelyblotoutrepentanceinthecruelesthearts，ifcriminalsarelaceratedbytheverymemoryoftheirdeeds，whyshouldwefrightentheimaginationofweakminds，byahell，byspecters，andbyprecipicesoffireevenlessrealthanthoseofPascal？Whymustwehaverecoursetofables，asanhonestpopeoncesaidhimself，totormenteventheunhappywretcheswhoareexecuted，becausewedonotthinkthattheyaresufficientlypunishedbytheirownconscience，theirfirstexecutioner？Idonotmeantosaythatallcriminalsareunjustlypunished；Ionlymaintainthatthosewhosewillisdepraved，andwhoseconscienceisextinguished，arepunishedenoughbytheirremorsewhentheycometothemselves，aremorse，Iventuretoassert，fromwhichnatureshouldinthiscasehavedeliveredunhappysoulsdraggedonbyafatalnecessity。
　　Criminals，scoundrels，ingrates，thoseinshortwithoutnaturalfeelings，unhappytyrantswhoareunworthyoflife，invaintakeacruelpleasureintheirbarbarity，fortherearecalmmomentsofreflectioninwhichtheavengingconsciencearises，testifiesagainstthem，andcondemnsthemtobealmostceaselesslytorntopiecesattheirownhands。Whoevertormentsmenistormentedbyhimself；andthesufferingsthathewillexperiencewillbethejustmeasureofthosethathehasinflicted。
　　Ontheotherhand，thereissomuchpleasureindoinggood，inrecognizingandappreciatingwhatonereceives，somuchsatisfactioninpractisingvirtue，inbeinggentle，humane，kind，charitable，compassionateandgenerous（forthisonewordincludesallthevirtues），thatIconsiderassufficientlypunishedanyonewhoisunfortunateenoughnottohavebeenbornvirtuous。
　　Wewerenotoriginallymadetobelearned；wehavebecomesoperhapsbyasortofabuseofourorganicfaculties，andattheexpenseoftheStatewhichnourishesahostofsluggardswhomvanityhasadornedwiththenameofphilosophers。Naturehascreatedusallsolelytobehappy-yes，allofusfromthecrawlingwormtotheeaglelostintheclouds。Forthiscauseshehasgivenallanimalssomeshareofnaturallaw，asharegreaterorlessaccordingtotheneedsofeachanimal’sorganswheninnormalcondition。
　　Nowhowshallwedefinenaturallaw？Itisafeelingthatteachesuswhatweshouldnotdo，becausewewouldnotwishittobedonetous。ShouldIdareaddtothiscommonidea，thatthisfeelingseemstomebutakindoffearordread，assalutarytotheraceastotheindividual；formayitnotbetruethatwerespectthepurseandlifeofothers，onlytosaveourownpossessions，ourhonor，andourselves；likethoseIxionsofChristianitywholoveGodandembracesomanyfantasticvirtues，merelybecausetheyareafraidofhell！
　　Youseethatnaturallawisbutanintimatefeelingthat，likeallotherfeelings（thoughtincluded）belongsalsotoimagination。
　　Evidently，therefore，naturallawdoesnotpresupposeeducation，revelation，norlegislator，-providedonedoesnotproposetoconfusenaturallawwithcivillaws，intheridiculousfashionofthetheologians。
　　Thearmsoffanaticismmaydestroythosewhosupportthesetruths，buttheywillneverdestroythetruthsthemselves。
　　Idonotmeantocallinquestiontheexistenceofasupremebeing；
　　onthecontraryitseemstomethatthegreatestdegreeofprobabilityisinfavorofthisbelief。Butsincetheexistenceofthisbeinggoesnofurtherthanthatofanyothertowardprovingtheneedofworship，itisatheoretictruthwithverylittlepracticalvalue。Therefore，sincewemaysay，aftersuchlongexperience，thatreligiondoesnotimplyexacthonesty，weareauthorizedbythesamereasonstothinkthatatheismdoesnotexcludeit。
　　Furthermore，whocanbesurethatthereasonforman’sexistenceisnotsimplythefactthatheexists？Perhapshewasthrownbychanceonsomespotontheearth’ssurface，nobodyknowshownorwhy，butsimplythathemustliveanddie，likethemushroomswhichappearfromdaytoday，orlikethoseflowerswhichbordertheditchesandcoverthewalls。
　　Letusnotloseourselvesintheinfinite，forwearenotmadetohavetheleastideathereof，andareabsolutelyunabletogetbacktotheoriginofthings。Besidesitdoesnotmatterforourpeaceofmind，whethermatterbeeternalorhavebeencreated，whethertherebeorbenotaGod。Howfoolishtotormentourselvessomuchaboutthingswhichwecannotknow，andwhichwouldnotmakeusanyhappierevenwerewetogainknowledgeaboutthem！
　　But，somewillsay，readallsuchworksasthoseofFé；nelon，ofNieuwentyt，ofAbadie，ofBerham，ofRais，andtherest。Well！
　　whatwilltheyteachmeorratherwhathavetheytaughtme？Theyareonlytiresomerepetitionsofzealouswriters，oneofwhomaddstotheotheronlyverbiage，morelikelytostrengthenthantounderminethefoundationsofatheism。Thenumberofevidencesdrawnfromthespectacleofnaturedoesnotgivetheseevidencesanymoreforce。Eitherthemerestructureofafinger，ofanear，ofaneye，asingleobservationofMalpighiprovesall，anddoubtlessmuchbetterthanDescartesandMalebrancheprovedit，oralltheotherevidencesprovenothing。Deists，andevenChristians，shouldthereforebecontenttopointoutthatthroughouttheanimalkingdomthesameaimsarepursuedandaccomplishedbyaninfinitenumberofdifferentmechanisms，allofthemhoweverexactlygeometrical。Forwhatstrongerweaponscouldtherebewithwhichtooverthrowatheists？Itistruethatifmyreasondoesnotdeceiveme，manandthewholeuniverseseemtohavebeendesignedforthisunityofaim。Thesun，air，water，theorganism，theshapeofbodies，-everythingisbroughttoafocusintheeyeasinamirrorthatfaithfullypresentstotheimaginationalltheobjectsreflectedinit，inaccordancewiththelawsrequiredbytheinfinitevarietyofbodieswhichtakepartinvision。Inearswefindeverywhereastrikingvariety，andyetthedifferenceofstructureinmen，animals，birds，andfishes，doesnotproducedifferentuses。Allearsaresomathematicallymade，thattheytendequallytooneandthesameend，namelyhearing。ButwouldChance，thedeistasks，beagreatenoughgeometriciantovarythus，atpleasure，theworksofwhichsheissupposedtobetheauthor，withoutbeinghinderedbysogreatadiversityfromgainingthesameend？
　　Again，thedeistwillbringforwardasadifficultythosepartsoftheanimalthatareclearlycontainedinitforfutureuse，thebutterflyinthecaterpillar，maninthesperm，awholepolypineachofitsparts，thevalvuleintheovalorifice，thelungsinthefoetus，theteethintheirsockets，thebonesinthefluidfromwhichtheydetachthemselvesand（inanincomprehensiblemanner）
　　harden。Andsincethepartisansofthistheory，farfromneglectinganythingthatwouldstrengthenproof，nevertireofpilingupproofuponproof，theyarewillingtoavailthemselvesofeverything，evenoftheweaknessofthemindincertaincases。Look，theysay，atmenlikeSpinoza，Vanini，Desbarreau，andBoindin，apostleswhohonordeismmorethantheyharmit。Thedurationoftheirhealthwasthemeasureoftheirunbelief，andonerarelyfails，theyadd，torenounceatheismwhenthepassions，withtheirinstrument，thebody，havegrownweak。
　　ThatiscertainlythemostthatcanbesaidinfavoroftheexistenceofGod：althoughthelastargumentisfrivolousinthattheseconversionsareshort，andthemindalmostalwaysregainsitsformeropinionsandactsaccordingly，assoonasithasregainedorratherrediscovereditsstrengthinthatofthebody。Thatis，atleast，muchmorethanwassaidbythephysicianDiderot，inhisPensé；esPhilosophiques，asublimeworkthatwillnotconvinceasingleatheist。Whatreplycan，intruth，bemadetoamanwhosays，``Wedonotknownature；causeshiddeninherbreastmighthaveproducedeverything。Inyourturn，observethepolypofTrembley：doesitnotcontaininitselfthecauseswhichbringaboutregeneration？Whythenwoulditbeabsurdtothinkthattherearephysicalcausesbyreasonofwhicheverythinghasbeenmade，andtowhichthewholechainofthisvastuniverseissonecessarilyboundandheldthatnothingwhichhappens，couldhavefailedtohappen，-causes，ofwhichwearesoinvinciblyignorantthatwehavehadrecoursetoaGod，who，assomeaver，isnotsomuchasalogicalentity？Thustodestroychanceisnottoprovetheexistenceofasupremebeing，sincetheremaybesomeotherthingwhichisneitherchancenorGod-
　　Imean，nature。Itfollowsthatthestudyofnaturecanonlymakeunbelievers；
　　andthewayofthinkingofallitsmoresuccessfulinvestigatorsprovesthis。’’
　　Theweightoftheuniversethereforefarfromcrushingarealatheistdoesnotevenshakehim。Alltheseevidencesofacreator，repeatedthousandsandthousandsoftimes，evidencethatareplacedfarabovethecomprehensionofmenlikeus，areself-evident（howeverfaronepushtheargument）onlytotheanti-Pyrrhonians，ortothosewhohaveenoughconfidenceintheirreasontopbelievethemselvescapableofjudgingonthebasisofcertainphenomena，againstwhich，asyousee，theatheistcanurgeothersperhapsequallystrongandabsolutelyopposed。Forifwelistentothenaturalistsagain，theywilltellusthattheverycauseswhich，inachemist’shands，byachancecombination，madethefirstmirror，inthehandsofnaturemadethepurewater，themirrorofthesimpleshepherdess；thatthemotionwhichkeepstheworldgoingcouldhavecreatedit，thateachbodyhastakentheplaceassignedtoitbyitsownnature，thattheairmusthavesurroundedtheearth，andthatironandtheothermetalsareproducedbytheinternalmotionsoftheearth，foroneandthesamereason；thatthesunisasmuchanaturalproductaselectricity，thatitwasnotmadetowarmtheearthanditsinhabitants，whomitsometimesburns，anymorethantherainwasmadetomaketheseedsgrow，whichitoftenspoils；thatthemirrorandthewaterwerenomoremadeforpeopletoseethemselvesin，thanwereallotherpolishedbodieswiththissameproperty；
　　thattheeyeisintruthakindofglassinwhichthesoulcancontemplatetheimageofobjectsastheyarepresentedtoitbythesebodies，butthatitisnotprovedthatthisorganwasreallymadeexpresslyforthiscontemplation，norpurposelyplacedinitssocket，andinshortitmaywellbethatLucretius，thephysicianLamy，andallEpicureansbothancientandmodernwererightwhentheysuggestedthattheeyeseesonlybecauseitisformedandplacedasitis，andthat，givenonceforall，thesamerulesofmotionfollowedbynatureinthegenerationanddevelopmentofbodies，thismarvelousorgancouldnothavebeenformedandplaceddifferently。
　　Suchistheproandthecon，andthesummaryofthosefineargumentsthatwilleternallydividethephilosophers。Idonottakeeitherside。
　　``Nonnostrumintervostantascompenerelites。’’
　　ThisiswhatIsaidtooneofmyfriends，aFrenchman，asfrankaPyrrhonianasI，amanofmuchmerit，andworthyofabetterfate。Hegavemeaverysingularanswerinregardtothematter。``Itistrue，’’hetoldme，``thattheproandconshouldnotdisturbatallthesoulofaphilosopher，whoseesthatnothingisprovedwithclearnessenoughtoforcehisconsent，andthattheargumentsofferedononesideareneutralizedbythoseoftheother。
　　However，’’hecontinued，``theuniversewillneverbehappy，unlessitisatheistic。’’Herearethiswretch’sreasons。Ifatheism，saidhe，weregenerallyaccepted，alltheformsofreligionwouldthenbedestroyedandcutoffattheroots。Nomoretheologicalwars，nomoresoldiersofreligion-suchterriblesoldiers！Natureinfectedwithasacredpoison，wouldregainitsrightsanditspurity。Deaftoallothervoices，tranquilmortalswouldfollowonthespontaneousdictatesoftheirownbeing，theonlycommandswhichcanneverbedespisedwithimpunityandwhichalonecanleadustohappinessthroughthepleasantpathsofvirtue。
　　Suchisnaturallaw：whoeverrigidlyobservesitisagoodmananddeservestheconfidenceofallthehumanrace。Whoeverfailstofollowitscrupulouslyaffects，invain，thespeciousexteriorofanotherreligion；heisascamporahypocritewhomIdistrust。
　　Afterthis，letavainpeoplethinkotherwise，letthemdareaffirmthatevenprobityisatstakeinnotbelievinginrevelation，inawordthatanotherreligionthanthatofnatureisnecessary，whateveritmaybe。Suchanassertioniswretchedandpitiable；andsoisthegoodopinionwhicheachonegivesusofthereligionhehasembraced！Wedonotseekherethevotesofthecrowd。
　　Whoeverraisesinhisheartaltarstosuperstition，isboundtoworshipidolsandnottothrilltovirtue。
　　Butsinceallthefacultiesofthesouldependtosuchadegreeontheproperorganizationofthebrainandofthewholebody，thatapparentlytheyarebutthisorganizationitself，thesoulisclearlyanenlightenedmachine。Forfinally，evenifmanalonehadreceivedashareofnaturallaw，wouldhebeanylessamachineforthat？Afewmorewheels，afewmorespringsthaninthemostperfectanimals，thebrainproportionallynearertheheartandforthisveryreasonreceivingmoreblood-anyoneofanumberofunknowncausesmightalwaysproducethisdelicateconsciencesoeasilywounded，thisremorsewhichisnomoreforeigntomatterthantothought，andinawordallthedifferencesthataresupposedtoexisthere。Couldtheorganismthensufficeforeverything？Oncemore，yes；sincethoughtvisiblydevelopswithourorgans，whyshouldnotthematterofwhichtheyarecomposedbesusceptibleofremorsealso，whenonceithasacquired，withtime，thefacultyoffeeling？
　　Thesoulisthereforebutanemptyword，ofwhichnoonehasanyidea，andwhichanenlightenedmanshouldonlyusetosignifythepartinusthatthinks。Giventheleastprincipleofmotion，animatedbodieswillhaveallthatisnecessaryformoving，feeling，thinking，repenting，orinawordforconductingthemselvesinthephysicalrealm，andinthemoralrealmwhichdependsuponit。
　　Yetwetakenothingforgranted；thosewhoperhapsthinkthatallthedifficultieshavenotyetbeenremovedshallnowreadofexperimentsthatwillcompletelysatisfythem。
　　1。Thefleshofallanimalspalpitatesafterdeath。Thispalpitationcontinueslonger，themorecoldbloodedtheanimalisandthelessitperspires。Tortoises，lizards，serpents，etc。areevidenceofthis。
　　2。Musclesseparatedfromthebodycontractwhentheyarestimulated。
　　3。Theintestineskeepuptheirperistalticorvermicularmotionforalongtime。
　　4。AccordingtoCowper，asimpleinjectionofhotwaterreanimatestheheartandthemuscles。
　　5。Afrog’sheartmovesforanhourormoreafterithasbeenremovedfromthebody，especiallywhenexposedtothesunorbetterstillwhenplacedonahottableorchair。Ifthismovementseemtotallylost，onehasonlytostimulatetheheart，andthathollowmusclebeatsagain。Harveymadethissameobservationontoads。
　　6。BaconofVerulaminhistreatiseSylvaSylvarumcitesthecaseofamanconvictedoftreason，whowasopenedalive，andwhoseheartthrownintohotwaterleapedseveraltimes，eachtimelesshigh，totheperpendicularheightoftwofeet。
　　7。Takeatinychickenstillintheegg，cutouttheheartandyouwillobservethesamephenomenaasbefore，underalmostthesameconditions。Thewarmthofthebreathalonereanimatesananimalabouttoperishintheairpump。
　　Thesameexperiments，whichweowetoBoyleandtoStenon，aremadeonpigeons，dogs，andrabbits。Piecesoftheirheartsbeatastheirwholeheartswould。Thesamemovementscanbeseeninpawsthathavebeencutofffrommoles。
　　8。Thecaterpillar，theworm，thespider，thefly，theeel-allexhibitthesamephenomena；andinhotwater，becauseofthefireitcontains，themovementofthedetachedpartsincreases。
　　9。AdrunkensoldiercutoffwithonestrokeofhissabreanIndianrooster’shead。Theanimalremainedstanding，thenwalked，andran：happeningtorunagainstawall，itturnedaround，beatsitswingsstillrunning，andfinallyfelldown。Asitlayontheground，allthemusclesofthisroosterkeptonmoving。ThatiswhatIsawmyself，andalmostthesamephenomenacaneasilybeobservedinkittensorpuppieswiththeirheadscutoff。
　　10。Polypsdomorethanmoveaftertheyhavebeencutinpieces。
　　Inaweektheyregeneratetoformasmanyanimalsastherearepieces。Iamsorrythatthesefactsspeakagainstthenaturalists’systemofgeneration；orratherIamverygladofit，forletthisdiscoveryteachusnevertoreachageneralconclusionevenonthegroundofallknown（andmostdecisive）experiments。
　　Herewehavemanymorefactsthanareneededtoprove，inanincontestableway，thateachtinyfiberorpartofanorganizedbodymovesbyaprinciplewhichbelongstoit。Itsactivity，unlikevoluntarymotions，doesnotdependinanywayonthenerves，sincethemovementsinquestionoccurinpartsofthebodywhichhavenoconnectionwiththecirculation。Butifthisforceismanifestedeveninsectionsoffiberstheheart，whichisacompositeofpeculiarlyconnectedfibers，mustpossessthesameproperty。IdidnotneedBacon’sstorytopersuademeofthis。Itwaseasyformetocometothisconclusion，bothfromtheperfectanalogyofthestructureofthehumanheartwiththatofanimals，andalsofromtheverybulkofthehumanheart，inwhichthismovementescapesoureyesonlybecauseitissmothered，andfinallybecauseincorpsesalltheorgansarecoldandlifeless。Ifexecutedcriminalsweredissectedwhiletheirbodiesarestillwarm，weshouldprobablyseeintheirheartsthesamemovementsthatareobservedintheface-musclesofthosethathavebeenbeheaded。
　　Themotiveprincipleofthewholebody，andevenofitspartscutinpieces，issuchthatitproducesnotirregularmovements，assomehavethought，butveryregularones，inwarmbloodedandperfectanimalsaswellasincoldandimperfectones。Noresourcethereforeremainsopentoouradversariesbuttodenythousandsandthousandsoffactswhicheverymancaneasilyverify。
　　Ifnowanyoneaskmewhereisthisinnateforceinourbodies，Ianswerthatitveryclearlyresidesinwhattheancientscalledtheparenchyma，thatistosay，intheverysubstanceoftheorgansnotincludingtheveins，thearteries，thenerves，inaword，thatitresidesintheorganizationofthewholebody，andthatconsequentlyeachorgancontainswithinitselfforcesmoreorlessactiveaccordingtotheneedofthem。
　　Letusnowgointosomedetailconcerningthesespringsofthehumanmachine。Allthevital，animal，natural，andautomaticmotionsarecarriedonbytheiraction。Isitnotinapurelymechanicalwaythatthebodyshrinksbackwhenitisstruckwithterroratthesightofanunforeseenprecipice，thattheeyelidsareloweredatthemenaceofablow，assomehaveremarked，andthatthepupilcontractsinbroaddaylighttosavetheretina，anddilatestoseeobjectsindarkness？Isitnotbymechanicalmeansthattheporesoftheskincloseinwintersothatthecoldcannotpenetratetotheinteriorofthebloodvessels，andthatthestomachvomitswhenitisirritatedbypoison，byacertainquantityofopiumandbyallemetics，etc。？thattheheart，thearteriesandthemusclescontractinsleepaswellasinwakinghours，thatthelungsserveasbellowscontinuallyinexercise，n’est-cepasmachinalementqu’agissenttouslessphinctersdelavessie，durectum，etc。？thattheheartcontractsmorestronglythananyothermuscle？quelesmusclesé；recteursfontdresserlavergedansl’homme，commedanslesanimauxquis’enbattentleventre，etmê；medansl’enfant，capabled’é；rection，pourpeuquecettepartiesoitirrité；e？Cequiprouve，pourledireenpassant，qu’ilestunressortsingulierdanscemembre，encorepeuconnu，etquiproduitdeseffetsqu’onn’apointencourebienexpliqué；s，malgré；
　　toutesleslumiè；resdel’anatomie。
　　Ishallnotgointoanymoredetailconcerningalltheselittlesubordinateforces，wellknowntoall。Butthereisanothermoresubtleandmarvelousforce，whichanimatesthemall；itisthesourceofallourfeelings，ofallourpleasures，ofallourpassions，andofallourthoughts：forthebrainhasitsmusclesforthinking，asthelegshavemusclesforwalking。IwishtospeakofthisimpetuousprinciplethatHippocratescallsenormon（soul）。Thisprincipleexistsandhasitsseatinthebrainattheoriginofthenerves，bywhichitexercisesitscontroloveralltherestofthebody。Bythisfactisexplainedallthatcanbeexplained，eventothesurprisingeffectofmaladiesoftheimagination。
　　Mais，pournepaslanguirdansunerichesseetunfé；condité；
　　malentendue，ilfautsebornerà；unpetitnombredequestionsetderé；flexions。
　　Pourquoilavueoulasimpleidé；ed’unebellefemmenouscause-t-elledesmouvementsetdesdé；sirssinguliers？Cequisepassealorsdanscertainsorganes，vient-ildelanaturemê；medecesorganes？Pointdutoutlmaisducommerceetdel’espè；cedesympathiedecesmusclesavecl’imagination。
　　Iln’yaiciqu’unpremierressortexcité；parlebeneplacitumdesanciens，ouparl’imagedelabeauté；，quienexciteunautre，lequelé；taitfortassoupi，quandl’imaginationl’aé；veillé；：etcommentcela，sicen’estparledé；sordreetletumultedusangetdesesprits，quigalopentavecunepromptitudeextraordinaire，etvontgonflerlescorpscaverneux？
　　Puisqu’ilestdescommincationsé；videntsentrelamè；reetl’enfant，etqu’ilestdurdenierdesfairrapporté；sparTulpiusetpard’autresé；crivainsaussidignesdefoi（iln’yenapointquilesoientplus），nouscroironsquec’estparlamê；mevoiequelefoetusressentl’impé；tuoisité；
　　del’imaginationmaternelle，commeuneciremollere&；ccedile；oittoutessortesd’impressions；etquelesmê；mestraces，ouenviesdelamè；re，peuvents’imprimersurlefoetus，sansquecelapuissesecomprendre，quoiqu’endisentBlondelettoussesadhé；renets。
　　Ainsinousfaisonsré；parationd’honneurauP。Malebranche，beaucouptropraillé；desacré；dulité；
　　parlesauteursquin’ontpointobservé；d’assexprè；slanatureetontvoulul’assujettirà；leuridé；es。
　　LookattheportraitofthefamousPopewhois，tosaytheleast，theVoltaireoftheEnglish。Theeffort，theenergyofhisgeniusareimprinteduponhiscountenance。Itisconvulsed。Hiseyesprotrudefromtheirsockets，theeyebrowsareraisedwiththemusclesoftheforehead。Why？Becausethebrainisintravailandallthebodymustshareinsuchalaboriousdeliverance。Iftherewerenotaninternalcordwhichpulledtheexternalones，whencewouldcomeallthesephenomena？Toadmitasoulasexplanationofthem，istobereducedto[explainingphenomenaby]
　　theoperationsoftheHolySpirit。
　　Infact，ifwhatthinksinmybrainisnotapartofthisorganandthereforeofthewholebody，whydoesmybloodboil，andthefeverofmymindpassintomyveins，whenlyingquietlyinbed，Iamformingtheplanofsomeworkorcarryingonanabstractcalculation？Putthisquestiontomenofimagination，togreatpoets，tomenwhoareenrapturedbythefelicitousexpressionofsentiment，andtransportedbyanexquisitefancyorbythecharmsofnature，oftruth，orofvirtue！Bytheirenthusiasm，bywhattheywilltellyoutheyhaveexperienced，youwilljudgethecausebyitseffects；bythatharmonywhichBorelli，amereanatomist，understoodbetterthanalltheLeibnizians，youwillcomprehendthematerialunityofman。Inshort，ifthenerve-tensionwhichcausespainoccasionsalsothefeverbywhichthedistractedmindloosesitswill-power，andif，conversely，themindtoomuchexcited，disturbsthebody（andkindlesthatinnerfirewhichkilledBaylewhilehewasstillsoyoung）lifanagitationrousesmydesireandmyardentwishforwhat，amomentago，Icarednothingabout，andifintheirturncertainbrainimpressionsexcitethesamelongingandthesamedesires，thenwhyshouldweregardasdoublewhatismanifestlyonebeing？
　　Invainyoufallbackonthepowerofthewill，sinceforoneorderthatthewillgives，itbowsahundredtimestotheyoke，Andwhatwonderthatinhealththebodyobeys，sinceatorrentofbloodandofanimalspiritsforcesitsobedience，andsincethewillhasasministersaninvisiblelegionoffluidsswifterthanlightningandeverreadytodoitsbidding！Butasthepowerofthewillisexercisedbymeansofthenerves，itislikewiselimitedbythem。Lameilleurevolonté；d’unamanté；puisé；，lesplusviolentdesiresluirendront-ilssavigueurperdue？Hé；las！non；etelleenseralapremiè；repunie，parce-que，posé；escertainescirconstances，iln’estpasdanssapuissancedenepasvouloirduplaisir。Cequej’aiditdelaparalysie，etc。revientici。
　　Doestheresultofjaundicesurpriseyou？Doyounotknowthatthecolorofbodiesdependsonthecoloroftheglassesthroughwhichwelookatthem，andthatwhateveristhecolorofthehumors，suchisthecolorofobjects，atleastforus，vainplaythingsofathousandillusions？Butremovethiscolorfromtheaqueoushumoroftheeye，letthebileflowthroughitsnaturalfilter，thenthesoulhavingneweyes，willnolongerseeyellow。Again，。isitnotthus，byremovingcataract，orbyinjectingtheEustachiancanal，thatsightisrestoredtotheblind，orhearingtothedeaf？
　　Howmanypeople，whowereperhapsonlyclevercharlatans，passedformiracleworkersinthedarkages！Beautifulthesoul，andpowerfulthewillwhichcannotactsavebypermissionofthebodilyconditions，andwhosetasteschangewithageandfever！
　　Shouldwe，then，beastonishedthatphilosophershavealwayshadinmindthehealthofthebody，topreservethehealthofthesoul，thatPythagorasgaverulesforthedietascarefullyasPlatoforbadewine？Theregimesuitedtothebodyisalwaystheonewithwhichsanephysiciansthinktheymustbegin，whenitisaquestionofformingthemind，andofinstructingitintheknowledgeoftruthandvirtue；butthesearevainwordsinthedisorderofillness，andinthetumultofthesenses。Withoutthepreceptsofhygiene，Epictetus，Socrates，Plato，andtherestpreachinvain：allethicsisfruitlessforonewholackshisshareoftemperance；itisthesourceofallvirtues，asintemperanceisthesourceofallvices。
　　Ismoreneeded，（forwhylosemyselfindiscussionofthepassionswhichareallexplainedbytheterm，enormon，ofHippocrates）toprovethatmanisbutananimal，oracollectionofspringswhichwindeachotherup，withoutorbeingabletotellatwhatpointinthishumancircle，naturehasbegun？Ifthesespringsdifferamongthemselves，thesedifferencesconsistonlyintheirpositionandintheirdegreesofstrength，andneverintheirnature；whereforethesoulisbutaprincipleofmotionoramaterialandsensiblepartofthebrain，whichcanberegarded，withoutfearoferror，asthemainspringofthewholemachine，havingavisibleinfluenceonalltheparts。Thesoulseemseventohavebeenmadeforthebrain，sothatallotherpartsofthesystemarebutakindofemanationfromthebrain。Thiswillappearfromcertainobservations，madeondifferentembryos，whichIshallnowenumerate。
　　Thisoscillation，whichisnaturalorsuitedtoourmachine，andwithwhicheachfibreandeveneachfibrouselement，sotospeak，seemstobeendowed，likethatofapendulum，cannotkeepupforever。Itmustberenewed，asitlosesstrength，invigoratedwhenitistired，andweakenedwhenitisdisturbedbyanexcessofstrengthandvigor。Inthisalone，truemedicineconsists。
　　Thebodyisbutawatch，whosewatchmakeristhenewchyle。Nature’sfirstcare，whenthechyleenterstheblood，istoexciteinitakindoffeverwhichthechemists，whodreamonlyofretorts，musthavetakenforfermentation。Thisfeverproducesagreaterfiltrationofspirits，whichmechanicallyanimatethemusclesandtheheart，asiftheyhadbeensenttherebyorderofthewill。
　　Thesethenarethecausesorforcesoflifewhichthussustainforahundredyearsthatperpetualmovementofthesolidsandliquidswhichisasnecessarytothefirstastothesecond。Butwhocansaywhetherthesolidscontributemorethanthefluidstothismovementorviceversa？Allthatweknowisthattheactionoftheformerwouldsoonceasewithoutthehelpofthelatter，thatis，withoutthehelpofthefluidswhichbytheironsetrouseandmaintaintheelasticityofthebloodvesselsonwhichtheirowncirculationdepends。Fromthisitfollowsthatafterdeaththenaturalresilienceofeachsubstanceisstillmoreorlessstrongaccordingtotheremnantsoflifewhichitoutlives，beingthelasttoperish。Sotrueisitthatthisforceoftheanimalpartscanbepreservedandstrengthenedbythatofthecirculation，butthatitdoesnotdependonthestrengthofthecirculation，since，aswehaveseen，itcandispensewitheventheintegrityofeachmemberororgan。
　　Iamawarethatthisopinionhasnotbeenrelishedbyallscholars，andthatStahlespeciallyhadmuchscornforit。Thisgreatchemisthadwishedtopersuadeusthatthesoulisthesolecauseofallourmovements。Butthisistospeakasafanaticandnotasaphilosopher。
　　TodestroythehypothesisofStahl，weneednotmakeasgreataneffortasIfindthatothershavedonebeforeme。Weneedonlyglanceataviolinist。Whatflexibility，whatlightnessinhisfingers！Themovementsaresoquick，thatitseemsalmostasiftherewerenosuccession。ButIpray，orratherIchallenge，thefollowersofStahlwhounderstandsoperfectlyallthatoursoulcando，totellmehowitcouldpossiblyexecutesomanymotionssoquickly，motions，moreover，whichtakeplacesofarfromthesoul，andinsomanydifferentplaces。Thatistosupposethatafluteplayercouldplaybrilliantcadencesonaninfinitenumberofholesthathecouldnotknow，andonwhichhecouldnotevenputhisfinger！
　　ButletussaywithM。HecquetthatallmenmaynotgotoCorinth。WhyshouldnotStahlhavebeenevenmorefavoredbynatureasamanthanasachemistandapractioner？Happymortal，hemusthavereceivedasouldifferentfromtherestofmankind，——-asovereignsoul，which，notcontentwithhavingsomecontroloverthevoluntarymuscles，easilyheldthereinsofallthemovementsofthebody，andcouldsuspendthem，calmthem，orexcitethematitspleasure！Withsodespoticamistress，inwhosehandswere，inasense，thebeatingoftheheart，andthelawsofcirculation，therecouldcertainlybenofever，nopain，noweariness，nihonteuseimpuissance，nifacheuxpriapisme！Thesoulwills，andthespringsplay，contractorrelax。ButhowdidthespringsofStahl’smachinegetoutofordersosoon？Hewhohasinhimselfsogreatadoctor，shouldbeimmortal。
　　Moreover，Stahlisnottheonlyonewhohasrejectedtheprincipleofthevibrationoforganicbodies。Greatermindshavenotusedtheprinciplewhentheywishedtoexplaintheactionsoftheheart，l’é；rectiondupenis，etc。OneneedonlyreadtheInstitutionsofMedicinebyBoerhaavetoseewhatlaboriousandenticingsystemsthisgreatmanwasobligedtoinvent，bythelaborofhismightygenius，throughfailuretoadmitthatthereissowonderfulaforceinallbodies。
　　WillisandPerrault，mindsofamorefeeblestamp，butcarefulobserversofnature（whereasnaturewasknowntothefamousLeydenprofessoronlythroughothersandsecondhand，sotospeak）
　　seemtohavepreferredtosupposeasoulgenerallyextendedoverthewholebody，insteadoftheprinciplewhichwearedescribing。Butaccordingtothishypothesis（whichwasthehypothesisofVergilandofallEpicureans，anhypothesiswhichthehistoryofthepolypmightseematfirstsighttofavor）themovementswhichgoonafterthedeathofthesubjectinwhichtheyinhereareduetoaremnantofsoulstillmaintainedbythepartsthatcontract，though，fromthemomentofdeath，thesearenotexcitedbythebloodandspirits。Whenceitmaybeseenthatthesewriters，whosesolidworkseasilyeclipseallphilosophicfables，aredeceivedonlyinthemannerofthosewhohaveendowedmatterwiththefacultyofthinking。Imeantosay，byhavingexpressedthemselvesbadlyinobscureandmeaninglessterms。Intruth，whatisthisremnantofasoul，ifitisnotthe``movingforce’’oftheLeibnizians（badlyrenderedbysuchanexpression），whichhoweverPerraultinparticularhasreallyforeseen。
　　SeehisTreatiseontheMechanismofAnimals。
　　NowthatitisclearlyprovedagainsttheCartesians，thefollowersofStahl，theMalebranchists，andthetheologianswholittledeservetobementionedhere，thatmatterisself-moved，notonlywhenorganized，asinawholeheart，forexample，butevenwhenthisorganizationhasbeendestroyed，humancuriositywouldliketodiscoverhowabody，bythefactthatitisoriginallyendowedwiththebreathoflife，findsitselfadornedinconsequencewiththefacultyoffeeling，andthuswiththatofthought。
　　And，heavens，whateffortshavenotbeenmadebycertainphilosopherstomanagetoprovethis！andwhatnonsenseofthissubjectIhavehadthepatiencetoread！
　　Allthatexperienceteachesusisthatwhilemovementpersists，howeverslightitmaybe，inoneormorefibres，weneedonlystimulatethemtore-exciteandanimatethismovementalmostextinguished。
　　ThishasbeenshowninthehostofexperimentswithwhichIhaveundertakentocrushthesystems。Itisthereforecertainthatmotionandfeelingexciteeachotherinturn，bothinawholebodyandinthesamebodywhenitsstructureisdestroyed，tosaynothingofcertainplantswhichseemtoexhibitthesamephenomenaoftheunionoffeelingandmotion。
　　Butfurthermore，howmanyexcellentphilosophershaveshownthatthoughtisbutafacultyoffeeling，andthatthereasonablesoulisbutthefeelingsoulengagedincontemplatingitsideasandinreasoning！Thiswouldbeprovedbythefactalonethatwhenfeelingisstifled，thoughtalsoischecked，forinstanceinapoplexy，inlethargy，incatalepsis，etc。Foritisridiculoustosuggestthat，duringthesestupors，thesoulkeepsonthinking，eventhoughitdoesnotremembertheideasthatithashad。
　　Astothedevelopmentoffeelingandmotion，itisabsurdtowastetimeseekingforitsmechanism。Thenatureofmotionisasunknowntousasthatofmatter。Howcanwediscoverhowitisproducedunless，liketheauthorofTheHistoryoftheSoul，weresuscitatetheoldandunintelligibledoctrineofsubstantialforms？
　　Iamthenquiteascontentnottoknowhowinertandsimplematterbecomesactiveandhighlyorganized，asnottobeabletolookatthesunwithoutredglasses；andIamaslittledisquietedconcerningtheotherincomprehensiblewondersofnature，theproductionoffeelingandofthoughtinabeingwhichearlierappearedtoourlimitedeyesasamereclodofclay。
　　Grantonlythatorganizedmatterisendowedwithaprincipleofmotion，whichalonedifferentiatesitfromtheinorganic（andcanonedenythisinthefaceofthemostincontestableobservation？）andthatamonganimals，asIhavesufficientlyproved，everythingdependsuponthediversityofthisorganization：theseadmissionssufficeforguessingtheriddleofsubstancesandofman。Itthusappearsthatthereisbutonetypeoforganizationintheuniverse，andthatmanisthemostperfectexample。Heistotheape，andtothemostintelligentanimals，astheplanetarypendulumofHuyghensistoawatchofJulienLeroy。Moreinstruments，morewheelsandmorespringswerenecessarytomarkthemovementsoftheplanetsthantomarkorstrikethehours；andVaucanson，whoneededmoreskillformakinghisfluteplayerthanformakinghisduck，wouldhaveneededstillmoretomakeatalkingman，amechanismnolongertoberegardedasimpossible，especiallyinthehandsofanotherPrometheus。Inlikefashion，itwasnecessarythatnatureshouldusemoreelaborateartinmakingandsustainingamachinewhichforawholecenturycouldmarkallmotionsoftheheartandofthemind；forthoughonedoesnottelltimebythepulse，itisatleastthebarometerofthewarmthandthevivacitybywhichonemayestimatethenatureofthesoul。Iamright！Thehumanbodyisawatch，alargewatchconstructedwithsuchskillandingenuity，thatifthewheelwhichmarksthesecondhappenstostop，theminutewheelturnsandkeepsongoingitsround，andinthesamewaythequarter-hourwheel，andalltheothersgoonrunningwhenthefirstwheelshavestoppedbecauserustyor，foranyreason，outoforder。Isitnotforasimilarreasonthatthestoppageofafewbloodvesselsisnotenoughtodestroyorsuspendthestrengthofthemovementwhichisintheheartasinthemainspringofthemachine；since，onthecontrary，thefluidswhosevolumeisdiminished，havingashorterroadtotravel，coverthegroundmorequickly，borneonasbyafreshcurrentwhichtheenergyoftheheartincreasesinproportiontotheresistanceitencountersattheendsoftheblood-vessels？Andisnotthisthereasonwhythelossofsight（causedbythecompressionoftheopticnerveanditsceasingtoconveytheimagesofobjects）nomorehindershearing，thanthelossofhearing（causedbytheobstructionofthefunctionsoftheauditorynerve）impliesthelossofsight？Inthesameway，finally，doesnotonemanhear（exceptimmediatelyafterhisattack）withoutbeingabletosaywhathehears，whileanotherwhohearsnothing，butwhoselingualnervesareuninjuredinthebrain，mechanicallytellsofallthedreamswhichpassthroughhismind？
　　Thesephenomenadonotsurpriseenlightenedphysiciansatall。Theyknowwhattothinkaboutman’snature（andmoreaccuratelytoexpressmyselfinpassing）oftwophysicians，thebetteroneandtheonewhodeservesmoreconfidenceisalways，inmyopinion，theonewhoismoreversedinthephysiqueormechanismofthehumanbody，andwho，leavingasidethesoulandalltheanxietieswhichthischimeragivestofoolsandtoignorantmen，isseriouslyoccupiedonlyinpurenaturalism。
　　ThereforeletthepretendedM。Charpderidephilosopherswhohaveregardedanimalsasmachines。Howdifferentismyview！
　　IbelievethatDescarteswouldbeamanineverywayworthyofrespect，if，borninacenturythathehadnotbeenobligedtoenlighten，hehadknownthevalueofexperimentandobservation，andthedangerofcuttingloosefromthem。Butitisnonethelessjustformetomakeanauthenticreparationtothisgreatmanforalltheinsignificantphilosophers——-poorjesters，andpoorimitatorsofLocke——-whoinsteadoflaughingimpudentlyatDescartes，mightbetterrealizethatwithouthimthefieldofphilosophy，likethefieldofsciencewithoutNewton，mightperhapsbestilluncultivated。
　　Thiscelebratedphilosopher，itistrue，wasmuchdeceived，andnoonedeniesthat。Butatanyrateheunderstoodanimalnature，hewasthefirsttoprovecompletelythatanimalsarepuremachines。Andafteradiscoveryofthisimportancedemandingsomuchsagacity，howcanwewithoutingratitudefailtopardonallhiserrors！
　　Inmyeyes，theyareallatonedforbythatgreatconfession。Forafterall，althoughheextolsthedistinctnessofthetwosubstances，thisisplainlybutatrickofskill，aruseofstyle，tomaketheologiansswallowapoison，hiddenintheshadeofananalogywhichstrikeseverybodyelseandwhichtheyalonefailtonotice。
　　Foritisthis，thisstronganalogy，whichforcesallscholarsandwisejudgestoconfessthattheseproudandvainbeings，moredistinguishedbytheirpridethanbythenameofmenhowevermuchtheymaywishtoexaltthemselves，areatbottomonlyanimalsandmachineswhich，thoughupright，goonallfours。Theyallhavethismarvelousinstinct，whichisdevelopedbyeducationintomind，andwhichalwayshasitsseatinthebrain（orforwantofthatwhenitislackingorhardened，inthemedullaoblongata）andneverinthecerebellum；forIhaveoftenseenthecerebelluminjured，andotherobservershavefoundithardened，whenthesoulhasnotceasedtofulfilitsfunctions。
　　Tobeamachine，tofeel，tothink，toknowhowtodistinguishgoodfrombad，aswellasbluefromyellow，inaword，tobebornwithanintelligenceandasuremoralinstinct，andtobebutananimal，arethereforecharacterswhicharenomorecontradictory，thantobeanapeoraparrotandtobeabletogiveoneselfpleasure。Car，puisquel’occasionsepré；sentedeledire，quieutjamaisdeviné；à；prioriqu’unegouttedelaliqeurquiselancedansl’accouplementfitressentirdesplaisirsdivins，etqu’ilennaî；traitunepetitecré；ature，quipourraitunjour，posé；escertaineslois，jouirdesmê；medé；lices？Ibelievethatthoughtissolittleincompatiblewithorganizedmatter，thatitseemstobeoneofitspropertiesonaparwithelectricity，thefacultyofmotion，impenetrability，extension，etc。
　　Doyouaskforfurtherobservations？Herearesomewhichareincontestableandwhichallprovethatmanresemblesanimalsperfectly，inhisoriginaswellasinallthepointsinwhichwehavethoughtitessentialtomakethecomparison。
　　J’enappaleà；labonnefoidenosobservateurs。Qu’ilsnousdisents’ilne’stpasvraiquel’hommedanssonprincipen’estqu’unver，quidevienthomme，commelachenillepaillon。Lesplusgravesauteurs[Boerhaave，Inst。Med。ettantd’autres]nousontappriscommentilfauts’yprendrepourvoircetanimalcule。Touslescurieuxl’ontvu，commeHartsoeker，danslasemencedel’homme，etnondanscelledelafemme；
　　iln’yaqueleplusadroit，ouleplusvigoreuxquiaitlaforcedes’insinueretdes’implanterdansl’oeufquefournitlafemme，etquiluidonnesapremiè；renourriture。
　　Cetoeuf，quelquefoissurprisdanslestrompesdeFallope，estporté；
　　parcescanauxà；lamatrice，où；ilprendracine，commeungraindeblé；danslaterre。Maisquoiqu’ilydeviennemonstru-euxparsacroissancede9mois，ilnediffè；repointdesoeufsdesautresfemelles，sicen’estquesapeau（l’amnios）
　　nesedurcitjamais，etsedilateprodigeusement，commeonenpeutjugerencomparantlesfoetustrové；sensituationetprè；sd’é；clore（cequej’aieuleplaisird’observerdansunefemmemorteunmomentavantl’accouchement），avecd’autrespetitsembryonstrè；sprochesdeleurorigine：caralorsc’esttoujoursl’oeufdanssacoque，etl’animaldansl’oeuf，qui，gê；né；danssesmouvements，cherchemachinalementà；voirlejour；etpouryré；ussir，ilcommenceparrompreaveclatê；tecettemembrance，d’oû；
　　ilsort，commelepulet，l’oiseau，etc。，delaleur。J’ajouteraiuneobservationquejenetrouvenullepart；c’estquel’amniosn’enestpasplusmince，pours’ê；treprodigieusementé；tendu；semblableencelaà；lamatricedontlasubstancemê；mesegonfledesucsinfiltré；s，indé；pendammentdelaré；plé；tionetdudé；ploiementdetoussescoudesvasculeux。
　　Letusobservemanbothinandoutofhisshell，letusexamineyoungembryosoffour，six，eightorfifteendayswithamicroscope；afterthattimeoureyesaresufficient。Whatdowesee？
　　Theheadalone；alittleroundeggwithtwoblackpointswhichmarktheeyes。Beforethat，everythingisformless，andoneseesonlyamedullarypulp，whichisthebrain，inwhichareformedfirsttherootsofthenerves，thatis，theprincipleoffeeling，andtheheart，whichalreadywithinthissubstancehasthepowerofbeatingofitself；itisthepunctumsaliensofMalpighi，whichperhapsalreadyowesapartofitsexcitabilitytotheinfluenceofthenerves。Thenlittlebylittle，oneseestheheadlengthenfromtheneck，which，indilating，formsfirstthethoraxinsidewhichthehearthasalreadysunk，theretobecomestationary；
　　belowthatistheabdomenwhichisdividedbyapartition（thediaphragm）。Oneoftheseenlargementsofthebodyformsthearms，thehands，thefingers，thenails，andthehair；theotherformsthethighs，thelegs，thefeet，etc。，whichdifferonlyintheirobservedsituation，andwhichconstitutethesupportandthebalancingpoleofthebody。Thewholeprocessisastrangesortofgrowth，likethatofplants。Onthetopsofourheadsishairinplaceofwhichtheplantshaveleavesandflowers；everywhereisshownthesameluxuryofnature，andfinallythedirectingprincipleofplantsisplacedwherewehaveoursoul，thatotherquintessenceofman。
　　Suchistheuniformityofnature，whichwearebeginningtorealize；
　　andtheanalogyoftheanimalwiththevegetablekingdom，ofmanwiththeplant。Perhapsthereevenareanimalplants，whichinvegetating，eitherfightaspolypsdo，orperformotherfunctionscharacteristicofanimals。
　　Voilà；à；peuprè；stoutcequ’onsaitdelagé；né；ration。
　　Quelespartiesquis’attirent，quisontfaitespurs’unirensembleetpouroccupertelleoutelleplace，seré；unissenttoutessuivantleurnature；etqu’ainsiseformentlesyeux，lecoeur，l’estomacetenfintoutlecorps，commedegranshommesl’onté；crit，celaestpossible。Mais，commel’expé；riencenousabandonneaumilieudescessubtilité；s，jenesupposerairien，regardanttoutcequinefrappepasmessenscommeunmystè；reimpé；netrable。Ilestsirarequelesdeuxemencesserencontrentdanslecongrè；s，quejeseraistenté；decroirequelasemencedelafemmeestinutileà；lagé；né；ration。
　　Maiscommentenexpliquerlesphé；nomè；nes，sanscecommoderapportdeparties，quirendsibienraisondesressemblancesdesenfants，tantô；taupè；re，ettantô；tà；lamè；re？D’unautrecô；té；，l’embarrasd’uneexplicationdoit-ellecontrebalancerunfait？Ilmeparaitquec’estlemâ；lequifaittout，dansunefemmequidorrt，commedanslapluslubrique。L’arrangementdespartiesseraitdonefaitdetouteé；ternité；danslegerme，oudanslevermê；medel’homme。Maistoutceciestfourtau-dessusdelaporté；edesplusexcellentsobservateurs。Commeilsn’ypeuventriensaisir，ilsnepeuventpasplusjugerdelamé；caniquedelaformationetdudé；veloppmentdescorps，qu’unetaupeducheminqu’uncerfpeutparcourir。
　　Weareveritablemolesinthefieldofnature；weachievelittlemorethanthemole’sjourneyanditsiourpridewhichprescribeslimitstothelimitless。Weareinthepositionofawatchthatshouldsay（awriteroffableswouldmakethewatchaheroinasillytale）：``Iwasnevermadebythatfoolofaworkman，Iwhodividetime，whomarksoexactlythecourseofthesun，whorepeataloudthehourswhichImark！No！thatisimpossible！’’Inthesameway，wedisdain，ungratefulwretchesthatweare，thiscommonmotherofallkingdoms，asthechemistssay。Weimagine，orratherweinfer，acausesuperiortothatwhichweoweall，andwhichtrulyhaswroughtallthingsinaninconceivablefashion。
　　No；mattercontainsnothingbase，excepttothevulgareyeswhichdonotrecognizeherinhermostsplendidworks；andnatureisnostupidworkman。Shecreatesmillionsofmen，withafacilityandapleasuremoreintensethantheeffortofawatchmakerinmakingthemostcomplicatedwatch。Herpowershinesforthequallyincreatingthelowliestinsectandincreatingthemosthighlydevelopedman；theanimalkingdomcostshernomorethanthevegetable，andthemostsplendidgeniusnomorethanabladeofwheat。Letusthenjudgebywhatweseeofthatwhichishiddenfromthecuriosityofoureyesandofourinvestigations，andletusnotimagineanythingbeyond。Letusobservetheape，thebeaver，theelephant，etc。，intheiroperations。
　　Ifitisclearthattheseactivitiescannotbeperformedwithoutintelligence，whyrefuseintelligencetotheseanimals？Andifyougrantthemasoulourarelost，youfanatics！Youwillinvainsaythatyouassertnothingaboutthenatureoftheanimalsoulandthatyoudenyitsimmortality。Whodoesnotseethatthisisagratuitousassertion；whodoesnotseethatthesoulofananimalmustbeeithermortalorimmortal，whicheveroursis，andthatitmustthereforeundergothesamefateasours，whateverthatmaybe，andthatthusinadmittingthatanimalshavesouls，youfallintoScyllainanefforttoavoidCharybdis？
　　Breakthechainofyourprejudices，armyourselveswiththetorchofexperience，andyouwillrendernaturethehonorshedeserves，insteadofinferringanythingtoherdisadvantage，fromtheignoranceinwhichshehasleftyou。Onlyopenwideyoureyes，onlydisregardwhatyoucannotunderstand，andyouwillseethattheploughmanwhoseintelligenceandideasextendnofurtherthantheboundsofhisfurrow，doesnotdifferessentiallyfromthegreatestgenius，——-atruthwhichthedissectionofDescartes’sandofNewton’sbrainswouldhaveproved；youwillbepersuadedthattheimbecileandthefoolareanimalswithhumanfaces，astheintelligentapeisalittlemaninanothershape；
　　inshort，youwilllearnthatsinceeverythingdependsabsolutelyondifferenceoforganization，awellconstructedanimalwhichhasstudiedastronomy，canpredictaneclipse，asitcanpredictrecoveryordeathwhenithasuseditsgeniusanditsclearnessofvision，foratime，intheschoolofHippocratesandatthebedsideofthesick。Bythislineofobservationsandtruths，wecometoconnecttheadmirablepowerofthoughtwithmatter，withoutbeingabletoseethelinks，becausethesubjectofthisattributeisessentiallyunknowntous。
　　Letusnotsaythateverymachineoreveryanimalperishesaltogetherorassumesanotherformafterdeath，forweknowabsolutelynothingaboutthesubject。Ontheotherhand，toassertthatanimmortalmachineisachimeraoralogicalfiction，istoreasonasabsurdlyascaterpillarswouldreasonif，seeingthecast-offskinsoftheirfellowcaterpillars，theyshouldbitterlydeplorethefateoftheirspecies，whichtothemwouldseemtocometonothing。Thesouloftheseinsects（foreachanimalhasitsown）istoolimitedtocomprehendthemetamorphosesofnature。
　　Neveroneofthemostskillfulamongthemcouldhaveimaginedthatitwasdestinedtobecomeabutterfly。Itisthesamewaywithus。Whatmoredoweknowofourdestinythanofourorigin？Letusthensubmittoaninvincibleignoranceonwhichourhappinessdepends。
　　Hewhosothinkswillbewise，just，tranquilabouthisfate，andthereforehappy。Hewillawaitdeathwithouteitherfearordesire，andwillcherishlife（hardlyunderstandinghowdisgustcancorruptaheartinthisplaceofmanydelights）；hewillbefilledwithreverence，gratitude，affection，andtendernessfornature，inproportiontohisfeelingofthebenefitshehasreceivedfromnature；hewillbehappy，inshort，infeelingnature，andinbeingpresentattheenchantingspectacleoftheuniverse，andwewillsurelyneverdestroynatureeitherinhimselforinothers。Morethanthat！Fullofhumanity，thismanwilllovehumancharactereveninhisenemies。Judgehowhewilltreatothers。Hewillpitythewickedwithouthatingthem；inhiseyes，theywillbebutmis-mademen。Butinpardoningthefaultsofthestructureofmindandbody，hewillnonethelessadmirethebeautiesandthevirtuesofboth。Thosewhomnatureshallhavefavoredwillseemtohimtodeservemorerespectthanthosewhomshehastreatedinstep-motherlyfashion。Thus，aswehaveseen，naturalgifts，thesourceofallacquirements，gainfromthelipsandheartofthematerialist，thehomagewhicheveryotherthinkerunjustlyrefusesthem。Inshort，thematerialist，convinced，inspiteoftheprotestsofhisvanity，thatishebutamachineorananimal，willnotmaltreathiskind，forhewillknowtoowellthenatureofthoseactions，whosehumanityisalwaysinproportiontothedegreeofanalogyprovedabove[betweenhumanbeingsandanimals]；andfollowingthenaturallawgiventoallanimals，hewillnotwishtodotootherswhathewouldnotwishthemtodotohim。
　　Letusthenconcludeboldlythatmanisamachine，andthatinthewholeuniversethereisbutasinglesubstancedifferentlymodified。Thisisnohypothesissetforthbydintofanumberofpostulatesandassumptions；itisnottheworkofprejudice，norevenofmyreasonalone；IshouldhavedisdainedaguidewhichIthinktobesountrustworthy，hadnotmysenses，bearingatorch，sotospeak，inducedmetofollowreasonbylightingthewaythemselves。Experiencehasthusspokentomeinbehalfofreason；andinthiswayIhavecombinedthetwo。
　　ButitmusthavebeennoticedthatIhavenotallowedmyselfeventhemostvigorousandimmediatelydeducedreasoning，exceptasaresultofamultitudeofobservationswhichnoscholarwillcontest；andfurthermore，IrecognizeonlyscholarsasjudgesoftheconclusionswhichIdrawfromtheobservations；andI
　　herebychallengeeveryprejudicedmanwhoisneitheranatomist，noracquaintedwiththeonlyphilosophywhichcanherebeconsidered，thatofthehumanbody。Againstsostrongandsolidanoak，whatcouldtheweakreedsoftheology，ofmetaphysics，andoftheschools，avail，————childisharms，likeourparlorfoils，thatmaywellaffordthepleasureoffencing，butcanneverwoundanadversary。NeedIsaythatIrefertotheemptyandtrivialnotions，tothepitiableandtriteargumentsthatwillbeurged（aslongastheshadowofprejudiceorofsuperstitionremainsonearthforthesupposeincompatibilityoftwosubstanceswhichmeetandmoveeachotherunceasingly？
　　Suchismysystem，orratherthetruth，unlessIammuchdeceived。
　　Itisshortandsimple。Disputeitnowwhowill。