Writingisaformofdrawing;thereforeifyougivethesameattentionandtroubletodrawingasyoudotowriting，dependuponit，thereisnobodywhocannotbemadetodraw，moreorlesswell.
Donotmisapprehendme.Idonotsayforonemomentyouwouldmakeanartisticdraughtsman.Artistsarenotmade;theygrow.Youmayimprovethenaturalfacultyinthatdirection，butyoucannotmakeit;butyoucanteachsimpledrawing，andyouwillfinditanimplementoflearningofextremevalue.Idonotthinkitsvaluecanbeexaggerated，becauseitgivesyouthemeansoftrainingtheyounginattentionandaccuracy，whicharethetwothingsinwhichallmankindaremoredeficientthaninanyothermentalqualitywhatever.Thewholeofmylifehasbeenspentintryingtogivemyproperattentiontothingsandtobeaccurate，andIhavenotsucceededaswellasIcouldwish;andotherpeople，Iamafraid，arenotmuchmorefortunate.Youcannotbeginthishabittooearly，andIconsiderthereisnothingofsogreatavalueasthehabitofdrawing，tosecurethosetwodesirableends.
Thenwecometothesubject—matter，whetherscientificoraesthetic，ofeducation，andIshouldnaturallyhavenoquestionatallaboutteachingtheelementsofphysicalscienceofthekindI
havesketched，inapracticalmanner;butamongscientifictopics，usingthewordscientificinthebroadestsense，Iwouldalsoincludetheelementsofthetheoryofmoralsandofthatofpoliticalandsociallife，which，strangelyenough，itneverseemstooccurtoanybodytoteachachild.Iwouldhavethehistoryofourowncountry，andofalltheinfluenceswhichhavebeenbroughttobearuponit，withincidentalgeography，notasamerechronicleofreignsandbattles，butasachapterinthedevelopmentoftherace，andthehistoryofcivilisation.
Thenwithrespecttoaestheticknowledgeanddiscipline，wehavehappilyintheEnglishlanguageoneofthemostmagnificentstorehousesofartisticbeautyandofmodelsofliteraryexcellencewhichexistsintheworldatthepresenttime.Ihavesaidbefore，andIrepeatithere，thatifamancannotgetliterarycultureofthehighestkindoutofhisBible，andChaucer，andShakespeare，andMilton，andHobbes，[81]andBishopBerkeley，[82]tomentiononlyafewofourillustriouswriters——Isay，ifhecannotgetitoutofthosewritershecannotgetitoutofanything;andIwouldassuredlydevoteaverylargeportionofthetimeofeveryEnglishchildtothecarefulstudyofthemodelsofEnglishwritingofsuchvariedandwonderfulkindaswepossess，and，whatisstillmoreimportantandstillmoreneglected，thehabitofusingthatlanguagewithprecision，withforce，andwithart.Ifancywearealmosttheonlynationintheworldwhoseemtothinkthatcompositioncomesbynature.TheFrenchattendtotheirownlanguage，theGermansstudytheirs;butEnglishmendonotseemtothinkitisworththeirwhile.NorwouldIfailtoinclude，inthecourseofstudyIamsketching，translationsofallthebestworksofantiquity，orofthemodernworld.ItisaverydesirablethingtoreadHomerinGreek;butifyoudon’thappentoknowGreek，thenextbestthingwecandoistoreadasgoodatranslationofitaswehaverecentlybeenfurnishedwithinprose.[83]Youwon’tgetallyouwouldgetfromtheoriginal，butyoumaygetagreatdeal;andtorefusetoknowthisgreatdealbecauseyoucannotgetall，seemstobeassensibleasforahungrymantorefusebreadbecausehecannotgetpartridge.Finally，Iwouldaddinstructionineithermusicorpainting，or，ifthechildshouldbesounhappy，assometimeshappens，astohavenofacultyforeitherofthose，andnopossibilityofdoinganythinginanyartisticsensewiththem，thenIwouldseewhatcouldbedonewithliteraturealone;butIwouldprovide，inthefullestsense，forthedevelopmentoftheaestheticsideofthemind.Inmyjudgment，thosearealltheessentialsofeducationforanEnglishchild.Withthatoutfit，suchasitmightbemadeinthetimegiventoeducationwhichiswithinthereachofnine—tenthsofthepopulation——withthatoutfit，anEnglishman，withinthelimitsofEnglishlife，isfittedtogoanywhere，tooccupythehighestpositions，tofillthehighestofficesoftheState，andtobecomedistinguishedinpracticalpursuits，inscience，orinart.For，ifhehavetheopportunitytolearnallthosethings，andhavehisminddisciplinedinthevariousdirectionstheteachingofthosetopicswouldhavenecessitated，then，assuredly，hewillbeabletopickup，onhisroadthroughlife，alltherestoftheintellectualbaggagehewants.
Iftheeducationaltimeatourdispositionweresufficient，thereareoneortwothingsIwouldaddtothoseIhavejustnowcalledtheessentials;andperhapsyouwillbesurprisedtohear，thoughI
hopeyouwillnot，thatIshouldadd，notmorescience，butone，or，ifpossible，twolanguages.Theknowledgeofsomeotherlanguagethanone’sownis，infact，ofsingularintellectualvalue.Manyofthefaultsandmistakesoftheancientphilosophersaretraceabletothefactthattheyknewnolanguagebuttheirown，andwereoftenledintoconfusingthesymbolwiththethoughtwhichitembodied.IthinkitisLocke[84]whosaysthatone—halfofthemistakesofphilosophershavearisenfromquestionsaboutwords;
andoneofthesafestwaysofdeliveringyourselffromthebondageofwordsis，toknowhowideaslookinwordstowhichyouarenotaccustomed.Thatisonereasonforthestudyoflanguage;anotherreasonis，thatitopensnewfieldsinartandinscience.Anotheristhepracticalvalueofsuchknowledge;andyetanotheristhis，thatifyourlanguagesareproperlychosen，fromthetimeoflearningtheadditionallanguagesyouwillknowyourownlanguagebetterthaneveryoudid.So，Isay，ifthetimegiventoeducationpermits，addLatinandGerman.Latin，becauseitisthekeytonearlyone—halfofEnglishandtoalltheRomancelanguages;
andGerman，becauseitisthekeytoalmostalltheremainderofEnglish，andhelpsyoutounderstandaracefromwhommostofushavesprung，andwhohaveacharacterandaliteratureofafatefulforceinthehistoryoftheworld，suchasprobablyhasbeenallottedtothoseofnootherpeople，excepttheJews，theGreeks，andourselves.Beyondthese，theessentialandtheeminentlydesirableelementsofalleducation，leteachmantakeuphisspecialline——thehistoriandevotehimselftohishistory，themanofsciencetohisscience，themanofletterstohiscultureofthatkind，andtheartisttohisspecialpursuit.
Baconhasprefacedsomeofhisworkswithnomorethanthis：
FranciscusBaconsiccogitavit;[85]let"siccogitavi"betheepiloguetowhatIhaveventuredtoaddresstoyouto—night.
THEMETHODOFSCIENTIFICINVESTIGATION[86]
Themethodofscientificinvestigationisnothingbuttheexpressionofthenecessarymodeofworkingofthehumanmind.Itissimplythemodeatwhichallphenomenaarereasonedabout，renderedpreciseandexact.Thereisnomoredifference，butthereisjustthesamekindofdifference，betweenthementaloperationsofamanofscienceandthoseofanordinaryperson，asthereisbetweentheoperationsandmethodsofabakerorofabutcherweighingouthisgoodsincommonscales，andtheoperationsofachemistinperformingadifficultandcomplexanalysisbymeansofhisbalanceandfinelygraduatedweights.Itisnotthattheactionofthescalesintheonecase，andthebalanceintheother，differintheprinciplesoftheirconstructionormannerofworking;butthebeamofoneissetonaninfinitelyfineraxisthantheother，andofcourseturnsbytheadditionofamuchsmallerweight.
Youwillunderstandthisbetter，perhaps，ifIgiveyousomefamiliarexample.Youhaveallhearditrepeated，Idaresay，thatmenofscienceworkbymeansofinductionanddeduction，andthatbythehelpoftheseoperations，they，inasortofsense，wringfromNaturecertainotherthings，whicharecallednaturallaws，andcauses，andthatoutofthese，bysomecunningskilloftheirown，theybuilduphypothesesandtheories.Anditisimaginedbymany，thattheoperationsofthecommonmindcanbebynomeanscomparedwiththeseprocesses，andthattheyhavetobeacquiredbyasortofspecialapprenticeshiptothecraft.Tohearalltheselargewords，youwouldthinkthatthemindofamanofsciencemustbeconstituteddifferentlyfromthatofhisfellowmen;butifyouwillnotbefrightenedbyterms，youwilldiscoverthatyouarequitewrong，andthatalltheseterribleapparatus[87]arebeingusedbyyourselveseverydayandeveryhourofyourlives.
Thereisawell—knownincidentinoneofMoliere’splays，[88]
wheretheauthormakestheheroexpressunboundeddelightonbeingtoldthathehadbeentalkingproseduringthewholeofhislife.
Inthesameway，Itrust，thatyouwilltakecomfort，andbedelightedwithyourselves，onthediscoverythatyouhavebeenactingontheprinciplesofinductiveanddeductivephilosophyduringthesameperiod.Probablythereisnotoneherewhohasnotinthecourseofthedayhadoccasiontosetinmotionacomplextrainofreasoning，oftheverysamekind，thoughdifferingofcourseindegree，asthatwhichascientificmangoesthroughintracingthecausesofnaturalphenomena.
Averytrivialcircumstancewillservetoexemplifythis.Supposeyougointoafruiterer’sshop，wantinganapple，——youtakeupone，and，onbitingit，youfinditissour;youlookatit，andseethatitishardandgreen.Youtakeupanotherone，andthattooishard，green，andsour.Theshopmanoffersyouathird;but，beforebitingit，youexamineit，andfindthatitishardandgreen，andyouimmediatelysaythatyouwillnothaveit，asitmustbesour，likethosethatyouhavealreadytried.
Nothingcanbemoresimplethanthat，youthink;butifyouwilltakethetroubletoanalyseandtraceoutintoitslogicalelementswhathasbeendonebythemind，youwillbegreatlysurprised.Inthefirstplaceyouhaveperformedtheoperationofinduction.Youfoundthat，intwoexperiences，hardnessandgreennessinappleswenttogetherwithsourness.Itwassointhefirstcase，anditwasconfirmedbythesecond.True，itisaverysmallbasis，butstillitisenoughtomakeaninductionfrom;yougeneralisethefacts，andyouexpecttofindsournessinappleswhereyougethardnessandgreenness.Youfounduponthatagenerallawthatallhardandgreenapplesaresour;andthat，sofarasitgoes，isaperfectinduction.Well，havinggotyournaturallawinthisway，whenyouareofferedanotherapplewhichyoufindishardandgreen，yousay，"Allhardandgreenapplesaresour;thisappleishardandgreen，thereforethisappleissour."Thattrainofreasoningiswhatlogicianscallasyllogism，andhasallitsvariouspartsandterms，——itsmajorpremiss，itsminorpremissanditsconclusion.And，bythehelpoffurtherreasoning，which，ifdrawnout，wouldhavetobeexhibitedintwoorthreeothersyllogisms，youarriveatyourfinaldetermination，"Iwillnothavethatapple."Sothat，yousee，youhave，inthefirstplace，establishedalawbyinduction，anduponthatyouhavefoundedadeduction，andreasonedoutthespecialparticularcase.Wellnow，suppose，havinggotyourconclusionofthelaw，thatatsometimeafterwards，youarediscussingthequalitiesofappleswithafriend：youwillsaytohim，"Itisaverycuriousthing，——butI
findthatallhardandgreenapplesaresour！"Yourfriendsaystoyou，"Buthowdoyouknowthat？"Youatoncereply，"Oh，becauseI
havetriedthemoverandoveragain，andhavealwaysfoundthemtobeso."Well，ifweweretalkingscienceinsteadofcommonsense，weshouldcallthatanexperimentalverification.And，ifstillopposed，yougofurther，andsay，"IhaveheardfromthepeopleinSomersetshireandDevonshire，wherealargenumberofapplesaregrown，thattheyhaveobservedthesamething.ItisalsofoundtobethecaseinNormandy，andinNorthAmerica.Inshort，Ifindittobetheuniversalexperienceofmankindwhereverattentionhasbeendirectedtothesubject."Whereupon，yourfriend，unlessheisaveryunreasonableman，agreeswithyou，andisconvincedthatyouarequiterightintheconclusionyouhavedrawn.Hebelieves，althoughperhapshedoesnotknowhebelievesit，thatthemoreextensiveverificationsare，——thatthemorefrequentlyexperimentshavebeenmade，andresultsofthesamekindarrivedat，——thatthemorevariedtheconditionsunderwhichthesameresultsareattained，themorecertainistheultimateconclusion，andhedisputesthequestionnofurther.Heseesthattheexperimenthasbeentriedunderallsortsofconditions，astotime，place，andpeople，withthesameresult;andhesayswithyou，therefore，thatthelawyouhavelaiddownmustbeagoodone，andhemustbelieveit.
Insciencewedothesamething;——thephilosopherexercisespreciselythesamefaculties，thoughinamuchmoredelicatemanner.Inscientificinquiryitbecomesamatterofdutytoexposeasupposedlawtoeverypossiblekindofverification，andtotakecare，moreover，thatthisisdoneintentionally，andnotlefttoamereaccident，asinthecaseoftheapples.Andinscience，asincommonlife，ourconfidenceinalawisinexactproportiontotheabsenceofvariationintheresultofourexperimentalverifications.Forinstance，ifyouletgoyourgraspofanarticleyoumayhaveinyourhand，itwillimmediatelyfalltotheground.Thatisaverycommonverificationofoneofthebestestablishedlawsofnature——thatofgravitation.Themethodbywhichmenofscienceestablishtheexistenceofthatlawisexactlythesameasthatbywhichwehaveestablishedthetrivialpropositionaboutthesournessofhardandgreenapples.Butwebelieveitinsuchanextensive，thorough，andunhesitatingmannerbecausetheuniversalexperienceofmankindverifiesit，andwecanverifyitourselvesatanytime;andthatisthestrongestpossiblefoundationonwhichanynaturallawcanrest.
Somuch，then，bywayofproofthatthemethodofestablishinglawsinscienceisexactlythesameasthatpursuedincommonlife.Letusnowturntoanothermatter（thoughreallyitisbutanotherphaseofthesamequestion），andthatis，themethodbywhich，fromtherelationsofcertainphenomena，weprovethatsomestandinthepositionofcausestowardstheothers.
Iwanttoputthecaseclearlybeforeyou，andIwillthereforeshowyouwhatImeanbyanotherfamiliarexample.Iwillsupposethatoneofyou，oncomingdowninthemorningtotheparlorofyourhouse，findsthatatea—potandsomespoonswhichhadbeenleftintheroomonthepreviouseveningaregone，——thewindowisopen，andyouobservethemarkofadirtyhandonthewindow—frame，andperhaps，inadditiontothat，younoticetheimpressofahob—
nailedshoeonthegraveloutside.Allthesephenomenahavestruckyourattentioninstantly，andbeforetwosecondshavepassedyousay，"Oh，somebodyhasbrokenopenthewindow，enteredtheroom，andrunoffwiththespoonsandthetea—pot！"Thatspeechisoutofyourmouthinamoment.Andyouwillprobablyadd，"Iknowtherehas;Iamquitesureofit！"Youmeantosayexactlywhatyouknow;butinrealityyouaregivingexpressiontowhatis，inallessentialparticulars，anhypothesis.YoudonotKNOWitatall;itisnothingbutanhypothesisrapidlyframedinyourownmind.Anditisanhypothesisfoundedonalongtrainofinductionsanddeductions.
Whatarethoseinductionsanddeductions，andhowhaveyougotatthishypothesis？Youhaveobservedinthefirstplace，thatthewindowisopen;butbyatrainofreasoninginvolvingmanyinductionsanddeductions，youhaveprobablyarrivedlongbeforeatthegenerallaw——andaverygoodoneitis——thatwindowsdonotopenofthemselves;andyouthereforeconcludethatsomethinghasopenedthewindow.Asecondgenerallawthatyouhavearrivedatinthesamewayis，thattea—potsandspoonsdonotgooutofawindowspontaneously，andyouaresatisfiedthat，astheyarenotnowwhereyouleftthem，theyhavebeenremoved.Inthethirdplace，youlookatthemarksonthewindowsill，andtheshoe—marksoutside，andyousaythatinallpreviousexperiencetheformerkindofmarkhasneverbeenproducedbyanythingelsebutthehandofahumanbeing;andthesameexperienceshowsthatnootheranimalbutmanatpresentwearsshoeswithhob—nailsinthemsuchaswouldproducethemarksinthegravel.Idonotknow，evenifwecoulddiscoveranyofthose"missinglinks"thataretalkedabout，thattheywouldhelpustoanyotherconclusion！Atanyratethelawwhichstatesourpresentexperienceisstrongenoughformypresentpurpose.Younextreachtheconclusionthat，asthesekind[89]ofmarkshavenotbeenleftbyanyotheranimalthanman，orareliabletobeformedinanyotherwaythanaman’shandandshoe，themarksinquestionhavebeenformedbyamaninthatway.Youhave，further，agenerallaw，foundedonobservationandexperience，andthat，too，is，Iamsorrytosay，averyuniversalandunimpeachableone，——thatsomemenarethieves;andyouassumeatoncefromallthesepremisses——andthatiswhatconstitutesyourhypothesis——thatthemanwhomadethemarksoutsideandonthewindow—sill，openedthewindow，gotintotheroom，andstoleyourtea—potandspoons.Youhavenowarrivedataveracausa;——youhaveassumedacausewhich，itisplain，iscompetenttoproduceallthephenomenayouhaveobserved.Youcanexplainallthesephenomenaonlybythehypothesisofathief.Butthatisahypotheticalconclusion，ofthejusticeofwhichyouhavenoabsoluteproofatall;itisonlyrenderedhighlyprobablebyaseriesofinductiveanddeductivereasonings.
Isupposeyourfirstaction，assumingthatyouareamanofordinarycommonsense，andthatyouhaveestablishedthishypothesistoyourownsatisfaction，willverylikelybetogooffforthepolice，andsetthemonthetrackoftheburglar，withtheviewtotherecoveryofyourproperty.Butjustasyouarestartingwiththisobject，somepersoncomesin，andonlearningwhatyouareabout，says，"Mygoodfriend，youaregoingonagreatdealtoofast.Howdoyouknowthatthemanwhoreallymadethemarkstookthespoons？Itmighthavebeenamonkeythattookthem，andthemanmayhavemerelylookedinafterwards."Youwouldprobablyreply，"Well，thatisallverywell，butyouseeitiscontrarytoallexperienceofthewaytea—potsandspoonsareabstracted;sothat，atanyrate，yourhypothesisislessprobablethanmine."Whileyouaretalkingthethingoverinthisway，anotherfriendarrives，oneofthegoodkindofpeoplethatIwastalkingofalittlewhileago.Andhemightsay，"Oh，mydearsir，youarecertainlygoingonagreatdealtoofast.Youaremostpresumptuous.Youadmitthatalltheseoccurrencestookplacewhenyouwerefastasleep，atatimewhenyoucouldnotpossiblyhaveknownanythingaboutwhatwastakingplace.HowdoyouknowthatthelawsofNaturearenotsuspendedduringthenight？Itmaybethattherehasbeensomekindofsupernaturalinterferenceinthiscase."Inpointoffact，hedeclaresthatyourhypothesisisoneofwhichyoucannotatalldemonstratethetruth，andthatyouarebynomeanssurethatthelawsofNaturearethesamewhenyouareasleepaswhenyouareawake.
Well，now，youcannotatthemomentanswerthatkindofreasoning.
Youfeelthatyourworthyfriendhasyousomewhatatadisadvantage.Youwillfeelperfectlyconvincedinyourownmind，however，thatyouarequiteright，andyousaytohim，"Mygoodfriend，Icanonlybeguidedbythenaturalprobabilitiesofthecase，andifyouwillbekindenoughtostandasideandpermitmetopass，Iwillgoandfetchthepolice."Well，wewillsupposethatyourjourneyissuccessful，andthatbygoodluckyoumeetwithapoliceman;thateventuallytheburglarisfoundwithyourpropertyonhisperson，andthemarkscorrespondtohishandandtohisboots.Probablyanyjurywouldconsiderthosefactsaverygoodexperimentalverificationofyourhypothesis，touchingthecauseoftheabnormalphenomenaobservedinyourparlor，andwouldactaccordingly.
Now，inthissupposititiouscase，Ihavetakenphenomenaofaverycommonkind，inorderthatyoumightseewhatarethedifferentstepsinanordinaryprocessofreasoning，ifyouwillonlytakethetroubletoanalyseitcarefully.AlltheoperationsIhavedescribed，youwillsee，areinvolvedinthemindofanymanofsenseinleadinghimtoaconclusionastothecourseheshouldtakeinordertomakegoodarobberyandpunishtheoffender.I
saythatyouareled，inthatcase，toyourconclusionbyexactlythesametrainofreasoningasthatwhichamanofsciencepursueswhenheisendeavouringtodiscovertheoriginandlawsofthemostoccultphenomena.Theprocessis，andalwaysmustbe，thesame;
andpreciselythesamemodeofreasoningwasemployedbyNewton[90]
andLaplace[91]intheirendeavourstodiscoveranddefinethecausesofthemovementsoftheheavenlybodies，asyou，withyourowncommonsense，wouldemploytodetectaburglar.Theonlydifferenceis，thatthenatureoftheinquirybeingmoreabstruse，everystephastobemostcarefullywatched，sothattheremaynotbeasinglecrackorflawinyourhypothesis.Aflaworcrackinmanyofthehypothesesofdailylifemaybeoflittleornomomentasaffectingthegeneralcorrectnessoftheconclusionsatwhichwemayarrive;
but，inascientificinquiry，afallacy，greatorsmall，isalwaysofimportance，andissuretobeinthelongrunconstantlyproductiveofmischievousifnotfatalresults.
Donotallowyourselvestobemisledbythecommonnotionthatanhypothesisisuntrustworthysimplybecauseitisanhypothesis.Itisoftenurged，inrespecttosomescientificconclusion，that，afterall，itisonlyanhypothesis.Butwhatmorehavewetoguideusinnine—tenthsofthemostimportantaffairsofdailylifethanhypotheses，andoftenveryill—basedones？Sothatinscience，wheretheevidenceofanhypothesisissubjectedtothemostrigidexamination，wemayrightlypursuethesamecourse.Youmayhavehypotheses，andhypotheses.Amanmaysay，ifhelikes，thatthemoonismadeofgreencheese：thatisanhypothesis.Butanotherman，whohasdevotedagreatdealoftimeandattentiontothesubject，andavailedhimselfofthemostpowerfultelescopesandtheresultsoftheobservationsofothers，declaresthatinhisopinionitisprobablycomposedofmaterialsverysimilartothoseofwhichourownearthismadeup：andthatisalsoonlyanhypothesis.ButIneednottellyouthatthereisanenormousdifferenceinthevalueofthetwohypotheses.Thatonewhichisbasedonsoundscientificknowledgeissuretohaveacorrespondingvalue;andthatwhichisamerehastyrandomguessislikelytohavebutlittlevalue.EverygreatstepinourprogressindiscoveringcauseshasbeenmadeinexactlythesamewayasthatwhichIhavedetailedtoyou.Apersonobservingtheoccurrenceofcertainfactsandphenomenaasks，naturallyenough，whatprocess，whatkindofoperationknowntooccurinNatureappliedtotheparticularcase，willunravelandexplainthemystery？Henceyouhavethescientifichypothesis;anditsvaluewillbeproportionatetothecareandcompletenesswithwhichitsbasishadbeentestedandverified.Itisinthesemattersasinthecommonestaffairsofpracticallife：theguessofthefoolwillbefolly，whiletheguessofthewisemanwillcontainwisdom.Inallcases，youseethatthevalueoftheresultdependsonthepatienceandfaithfulnesswithwhichtheinvestigatorappliestohishypothesiseverypossiblekindofverification.
ONTHEPHYSICALBASISOFLIFE[92]
Inordertomakethetitleofthisdiscoursegenerallyintelligible，Ihavetranslatedtheterm"Protoplasm，"whichisthescientificnameofthesubstanceofwhichIamabouttospeak，bythewords"thephysicalbasisoflife."Isupposethat，tomany，theideathatthereissuchathingasaphysicalbasis，ormatter，oflifemaybenovel——sowidelyspreadistheconceptionoflifeasasomethingwhichworksthroughmatter，butisindependentofit;
andeventhosewhoareawarethatmatterandlifeareinseparablyconnected，maynotbepreparedfortheconclusionplainlysuggestedbythephrase，"THEphysicalbasisormatteroflife，"thatthereissomeonekindofmatterwhichiscommontoalllivingbeings，andthattheirendlessdiversitiesareboundtogetherbyaphysical，aswellasanideal，unity.Infact，whenfirstapprehended，suchadoctrineasthisappearsalmostshockingtocommonsense.
What，truly，canseemtobemoreobviouslydifferentfromoneanother，infaculty，inform，andinsubstance，thanthevariouskindsoflivingbeings？Whatcommunityoffacultycantherebebetweenthebright—colouredlichen，whichsonearlyresemblesameremineralincrustationofthebarerockonwhichitgrows，andthepainter，towhomitisinstinctwithbeauty，orthebotanist，whomitfeedswithknowledge？
Again，thinkofthemicroscopicfungus——amereinfinitesimalovoidparticle，whichfindsspaceanddurationenoughtomultiplyintocountlessmillionsinthebodyofalivingfly;andthenofthewealthoffoliage，theluxurianceofflowerandfruit，whichliesbetweenthisbaldsketchofaplantandthegiantpineofCalifornia，toweringtothedimensionsofacathedralspire，ortheIndianfig，whichcoversacreswithitsprofoundshadow，andendureswhilenationsandempirescomeandgoarounditsvastcircumference.Or，turningtotheotherhalfoftheworldoflife，picturetoyourselvesthegreatFinnerwhale，[93]hugestofbeaststhatlive，orhavelived，disportinghiseightyorninetyfeetofbone，muscleandblubber，witheasyroll，amongwavesinwhichthestoutestshipthateverleftdockyardwouldflounderhopelessly;
andcontrasthimwiththeinvisibleanimalcules——meregelatinousspecks，multitudesofwhichcould，infact，danceuponthepointofaneedlewiththesameeaseastheangelsoftheSchoolmencould，inimagination.Withtheseimagesbeforeyourminds，youmaywellask，whatcommunityofform，orstructure，istherebetweentheanimalculeandthewhale;orbetweenthefungusandthefig—tree？
And，afortiori，[94]betweenallfour？
Finally，ifweregardsubstance，ormaterialcomposition，whathiddenbondcanconnecttheflowerwhichagirlwearsinherhairandthebloodwhichcoursesthroughheryouthfulveins;or，whatisthereincommonbetweenthedenseandresistingmassoftheoak，orthestrongfabricofthetortoise，andthosebroaddisksofglassyjellywhichmaybeseenpulsatingthroughthewatersofacalmsea，butwhichdrainawaytomerefilmsinthehandwhichraisesthemoutoftheirelement？
Suchobjectionsasthesemust，Ithink，ariseinthemindofeveryonewhoponders，forthefirsttime，upontheconceptionofasinglephysicalbasisoflifeunderlyingallthediversitiesofvitalexistence;butIproposetodemonstratetoyouthat，notwithstandingtheseapparentdifficulties，athreefoldunity——
namely，aunityofpowerorfaculty，aunityofform，andaunityofsubstantialcomposition——doespervadethewholelivingworld.
Noveryabstruseargumentationisneeded，inthefirstplacetoprovethatthepowers，orfaculties，ofallkindsoflivingmatter，diverseastheymaybeindegree，aresubstantiallysimilarinkind.
Goethehascondensedasurveyofallpowersofmankindintothewell—knownepigram：——[95]
"WarumtreibtsichdasVolksoundschreit？EswillsichernahrenKinderzeugen，unddienahrensogutesvermag
WeiterbringteskeinMensch，stell’ersichwieerauchwill."
Inphysiologicallanguagethismeans，thatallthemultifariousandcomplicatedactivitiesofmanarecomprehensibleunderthreecategories.Eithertheyareimmediatelydirectedtowardsthemaintenanceanddevelopmentofthebody，ortheyeffecttransitorychangesintherelativepositionsofpartsofthebody，ortheytendtowardsthecontinuanceofthespecies.Eventhosemanifestationsofintellect，offeeling，andofwill，whichwerightlynamethehigherfaculties，arenotexcludedfromthisclassification，inasmuchastoeveryonebutthesubjectofthem，theyareknownonlyastransitorychangesintherelativepositionsofpartsofthebody.Speech，gesture，andeveryotherformofhumanactionare，inthelongrun，resolvableintomuscularcontraction，andmuscularcontractionisbutatransitorychangeintherelativepositionsofthepartsofamuscle.Buttheschemewhichislargeenoughtoembracetheactivitiesofthehighestformoflife，coversallthoseofthelowercreatures.Thelowestplant，oranimalcule，feeds，grows，andreproducesitskind.Inaddition，allanimalsmanifestthosetransitorychangesofformwhichweclassunderirritabilityandcontractility;and，itismorethanprobable，thatwhenthevegetableworldisthoroughlyexplored，weshallfindallplantsinpossessionofthesamepowers，atonetimeorotheroftheirexistence.
Iamnotnowalludingtosuchphaenomena，atoncerareandconspicuous，asthoseexhibitedbytheleafletsofthesensitiveplants，orthestamensofthebarberry，buttomuchmorewidelyspread，andatthesametime，moresubtleandhidden，manifestationsofvegetablecontractility.Youaredoubtlessawarethatthecommonnettleowesitsstingingpropertytotheinnumerablestiffandneedle—like，thoughexquisitelydelicate，hairswhichcoveritssurface.Eachstinging—needletapersfromabroadbasetoaslendersummit，which，thoughroundedattheend，isofsuchmicroscopicfinenessthatitreadilypenetrates，andbreaksoffin，theskin.Thewholehairconsistsofaverydelicateoutercaseofwood，closelyappliedtotheinnersurfaceofwhichisalayerofsemi—fluidmatter，fullofinnumerablegranulesofextrememinuteness.Thissemi—fluidliningisprotoplasm，whichthusconstitutesakindofbag，fullofalimpidliquid，androughlycorrespondinginformwiththeinteriorofthehairwhichitfills.Whenviewedwithasufficientlyhighmagnifyingpower，theprotoplasmiclayerofthenettlehairisseentobeinaconditionofunceasingactivity.Localcontractionsofthewholethicknessofitssubstancepassslowlyandgraduallyfrompointtopoint，andgiverisetotheappearanceofprogressivewaves，justasthebendingofsuccessivestalksofcornbyabreezeproducestheapparentbillowsofacornfield.
But，inadditiontothesemovements，andindependentlyofthem，thegranulesaredriven，inrelativelyrapidstreams，throughchannelsintheprotoplasmwhichseemtohaveaconsiderableamountofpersistence.Mostcommonly，thecurrentsinadjacentpartsoftheprotoplasmtakesimilardirections;and，thus，thereisageneralstreamuponesideofthehairanddowntheother.Butthisdoesnotpreventtheexistenceofpartialcurrentswhichtakedifferentroutes;andsometimestrainsofgranulesmaybeseencoursingswiftlyinoppositedirectionswithinatwenty—thousandthofaninchofoneanother;while，occasionally，oppositestreamscomeintodirectcollision，and，afteralongerorshorterstruggle，onepredominates.Thecauseofthesecurrentsseemstolieincontractionsoftheprotoplasmwhichboundsthechannelsinwhichtheyflow，butwhicharesominutethatthebestmicroscopesshowonlytheireffects，andnotthemselves.
Thespectacleaffordedbythewonderfulenergiesprisonedwithinthecompassofthemicroscopichairofaplant，whichwecommonlyregardasamerelypassiveorganism，isnoteasilyforgottenbyonewhohaswatcheditsdisplay，continuedhourafterhour，withoutpauseorsignofweakening.Thepossiblecomplexityofmanyotherorganicforms，seeminglyassimpleastheprotoplasmofthenettle，dawnsuponone;andthecomparisonofsuchaprotoplasmtoabodywithaninternalcirculation，whichhasbeenputforwardbyaneminentphysiologist，losesmuchofitsstartlingcharacter.
Currentssimilartothoseofthehairsofthenettlehavebeenobservedinagreatmultitudeofverydifferentplants，andweightyauthoritieshavesuggestedthattheyprobablyoccur，inmoreorlessperfection，inallyoungvegetablecells.Ifsuchbethecase，thewonderfulnoondaysilenceofatropicalforestis，afterall，dueonlytothedulnessofourhearing;andcouldourearscatchthemurmurofthesetinyMaelstroms，[96]astheywhirlintheinnumerablemyriadsoflivingcellswhichconstituteeachtree，weshouldbestunned，aswiththeroarofagreatcity.
Amongthelowerplants，itistheruleratherthantheexception，thatcontractilityshouldbestillmoreopenlymanifestedatsomeperiodsoftheirexistence.TheprotoplasmofAlgaeandFungibecomes，undermanycircumstances，partially，orcompletely，freedfromitswoodycase，andexhibitsmovementsofitswholemass，orispropelledbythecontractilityofone，ormore，hair—likeprolongationsofitsbody，whicharecalledvibratilecilia.And，sofarastheconditionsofthemanifestationofthephaenomenaofcontractilityhaveyetbeenstudied，theyarethesamefortheplantasfortheanimal.Heatandelectricshocksinfluenceboth，andinthesameway，thoughitmaybeindifferentdegrees.Itisbynomeansmyintentiontosuggestthatthereisnodifferenceinfacultybetweenthelowestplantandthehighest，orbetweenplantsandanimals.Butthedifferencebetweenthepowersofthelowestplant，oranimal，andthoseofthehighest，isoneofdegree，notofkind，anddepends，asMilne—Edwards[97]longagosowellpointedout，upontheextenttowhichtheprincipleofthedivisionoflabouriscarriedoutinthelivingeconomy.Inthelowestorganismallpartsarecompetenttoperformallfunctions，andoneandthesameportionofprotoplasmmaysuccessfullytakeonthefunctionoffeeding，moving，orreproducingapparatus.Inthehighest，onthecontrary，agreatnumberofpartscombinetoperformeachfunction，eachpartdoingitsallottedshareoftheworkwithgreataccuracyandefficiency，butbeinguselessforanyotherpurpose.
Ontheotherhand，notwithstandingallthefundamentalresemblanceswhichexistbetweenthepowersoftheprotoplasminplantsandinanimals，theypresentastrikingdifference（towhichIshalladvertmoreatlengthpresently），inthefactthatplantscanmanufacturefreshprotoplasmoutofmineralcompounds，whereasanimalsareobligedtoprocureitreadymade，andhence，inthelongrun，dependuponplants.Uponwhatconditionthisdifferenceinthepowersofthetwogreatdivisionsoftheworldoflifedepends，nothingisatpresentknown.
Withsuchqualificationsasarises[98]outofthelast—mentionedfact，itmaybetrulysaidthattheactsofalllivingthingsarefundamentallyone.Isanysuchunitypredicableoftheirforms？
Letusseekineasilyverifiedfactsforareplytothisquestion.
Ifadropofbloodbedrawnbyprickingone’sfinger，andviewedwithproperprecautions，andunderasufficientlyhighmicroscopicpower，therewillbeseen，amongtheinnumerablemultitudeoflittle，circular，discoidalbodies，orcorpuscles，whichfloatinitandgiveititscolour，acomparativelysmallnumberofcolourlesscorpuscles，ofsomewhatlargersizeandveryirregularshape.Ifthedropofbloodbekeptatthetemperatureofthebody，thesecolourlesscorpuscleswillbeseentoexhibitamarvellousactivity，changingtheirformswithgreatrapidity，drawinginandthrustingoutprolongationsoftheirsubstance，andcreepingaboutasiftheywereindependentorganisms.
Thesubstancewhichisthusactiveisamassofprotoplasm，anditsactivitydiffersindetail，ratherthaninprinciple，fromthatoftheprotoplasmofthenettle.Undersundrycircumstancesthecorpusclediesandbecomesdistendedintoaroundmass，inthemidstofwhichisseenasmallersphericalbody，whichexisted，butwasmoreorlesshidden，inthelivingcorpuscle，andiscalleditsnucleus.Corpusclesofessentiallysimilarstructurearetobefoundintheskin，intheliningofthemouth，andscatteredthroughthewholeframeworkofthebody.Nay，more;intheearliestconditionofthehumanorganism，inthatstateinwhichithasbutjustbecomedistinguishablefromtheegginwhichitarises，itisnothingbutanaggregationofsuchcorpuscles，andeveryorganofthebodywas，once，nomorethansuchanaggregation.
Thusanucleatedmassofprotoplasmturnsouttobewhatmaybetermedthestructuralunitofthehumanbody.Asamatteroffact，thebody，initsearlieststate，isameremultipleofsuchunits;
andinitsperfectcondition，itisamultipleofsuchunits，variouslymodified.
Butdoestheformulawhichexpressestheessentialstructuralcharacterofthehighestanimalcoveralltherest，asthestatementofitspowersandfacultiescoveredthatofallothers？
Verynearly.Beastandfowl，reptileandfish，mollusk，worm，andpolype，areallcomposedofstructuralunitsofthesamecharacter，namely，massesofprotoplasmwithanucleus.Therearesundryverylowanimals，eachofwhich，structurally，isamerecolourlessblood—corpuscle，leadinganindependentlife.But，attheverybottomoftheanimalscale，eventhissimplicitybecomessimplified，andallthephaenomenaoflifearemanifestedbyaparticleofprotoplasmwithoutanucleus.Noraresuchorganismsinsignificantbyreasonoftheirwantofcomplexity.Itisafairquestionwhethertheprotoplasmofthosesimplestformsoflife，whichpeopleanimmenseextentofthebottomofthesea，wouldnotoutweighthatofallthehigherlivingbeingswhichinhabitthelandputtogether.Andinancienttimes，nolessthanatthepresentday，suchlivingbeingsasthesehavebeenthegreatestofrockbuilders.
Whathasbeensaidoftheanimalworldisnolesstrueofplants.
Imbeddedintheprotoplasmatthebroad，orattached，endofthenettlehair，thereliesaspheroidalnucleus.Carefulexaminationfurtherprovesthatthewholesubstanceofthenettleismadeupofarepetitionofsuchmassesofnucleatedprotoplasm，eachcontainedinawoodencase，whichismodifiedinform，sometimesintoawoodyfibre，sometimesintoaductorspiralvessel，sometimesintoapollengrain，oranovule.Tracedbacktoitsearlieststate，thenettlearisesasthemandoes，inaparticleofnucleatedprotoplasm.Andinthelowestplants，asinthelowestanimals，asinglemassofsuchprotoplasmmayconstitutethewholeplant，ortheprotoplasmmayexistwithoutanucleus.
Underthesecircumstancesitmaywellbeasked，howisonemassofnon—nucleatedprotoplasmtobedistinguishedfromanother？whycallone"plant"andtheother"animal"？
Theonlyreplyisthat，sofarasformisconcerned，plantsandanimalsarenotseparable，andthat，inmanycases，itisamerematterofconventionwhetherwecallagivenorganismananimaloraplant.ThereisalivingbodycalledAethaliumsepticum，whichappearsupondecayingvegetablesubstances，and，inoneofitsforms，iscommonuponthesurfacesoftan—pits.Inthisconditionitis，toallintentsandpurposes，afungus，andformerlywasalwaysregardedassuch;buttheremarkableinvestigationsofDeBary[99]haveshownthat，inanothercondition，theAethaliumisanactivelylocomotivecreature，andtakesinsolidmatters，uponwhich，apparently，itfeeds，thusexhibitingthemostcharacteristicfeatureofanimality.Isthisaplant;orisitananimal？
Isitboth;orisitneither？Somedecideinfavourofthelastsupposition，andestablishanintermediatekingdom，asortofbiologicalNoMan’sLand[100]forallthesequestionableforms.
But，asitisadmittedlyimpossibletodrawanydistinctboundarylinebetweenthisnoman’slandandthevegetableworldontheonehand，ortheanimal，ontheother，itappearstomethatthisproceedingmerelydoublesthedifficultywhich，before，wassingle.
Protoplasm，simpleornucleated，istheformalbasisofalllife.
Itistheclayofthepotter：which，bakeitandpaintitashewill，remainsclay，separatedbyartifice，andnotbynature，fromthecommonestbrickorsun—driedclod.
Thusitbecomesclearthatalllivingpowersarecognate，andthatalllivingformsarefundamentallyofonecharacter.Theresearchesofthechemisthaverevealedanolessstrikinguniformityofmaterialcompositioninlivingmatter.
Inperfectstrictness，itistruethatchemicalinvestigationcantelluslittleornothing，directly，ofthecompositionoflivingmatter，inasmuchassuchmattermustneedsdieintheactofanalysis，——anduponthisveryobviousground，objections，whichI
confessseemtometobesomewhatfrivolous，havebeenraisedtothedrawingofanyconclusionswhateverrespectingthecompositionofactuallylivingmatter，fromthatofthedeadmatteroflife，whichaloneisaccessibletous.Butobjectorsofthisclassdonotseemtoreflectthatitisalso，instrictness，truethatweknownothingaboutthecompositionofanybodywhatever，asitis.
Thestatementthatacrystalofcalc—sparconsistsofcarbonateoflime，isquitetrue，ifweonlymeanthat，byappropriateprocesses，itmayberesolvedintocarbonicacidandquicklime.Ifyoupassthesamecarbonicacidovertheveryquicklimethusobtained，youwillobtaincarbonateoflimeagain;butitwillnotbecalc—spar，noranythinglikeit.Canit，therefore，besaidthatchemicalanalysisteachesnothingaboutthechemicalcompositionofcalc—spar？Suchastatementwouldbeabsurd;butitishardlymoresothanthetalkoneoccasionallyhearsabouttheuselessnessofapplyingtheresultsofchemicalanalysistothelivingbodieswhichhaveyieldedthem.
Onefact，atanyrate，isoutofreachofsuchrefinements，andthisis，thatalltheformsofprotoplasmwhichhaveyetbeenexaminedcontainthefourelements，carbon，hydrogen，oxygen，andnitrogen，inverycomplexunion，andthattheybehavesimilarlytowardsseveralreagents.Tothiscomplexcombination，thenatureofwhichhasneverbeendeterminedwithexactness，thenameofProteinhasbeenapplied.Andifweusethistermwithsuchcautionasmayproperlyariseoutofourcomparativeignoranceofthethingsforwhichitstands，itmaybetrulysaid，thatallprotoplasmisproteinaceous，or，asthewhite，oralbumen，ofaneggisoneofthecommonestexamplesofanearlypureproteinematter，wemaysaythatalllivingmatterismoreorlessalbuminoid.
Perhapsitwouldnotyetbesafetosaythatallformsofprotoplasmareaffectedbythedirectactionofelectricshocks;
andyetthenumberofcasesinwhichthecontractionofprotoplasmisshowntobeaffectedbythisagencyincreaseseveryday.
Norcanitbeaffirmedwithperfectconfidence，thatallformsofprotoplasmareliabletoundergothatpeculiarcoagulationatatemperatureof40—50degreescentigrade，whichhasbeencalled"heat—stiffening，"thoughKuhne’s[101]beautifulresearcheshaveprovedthisoccurrencetotakeplaceinsomanyandsuchdiverselivingbeings，thatitishardlyrashtoexpectthatthelawholdsgoodforall.
Enoughhas，perhaps，beensaidtoprovetheexistenceofageneraluniformityinthecharacteroftheprotoplasm，orphysicalbasis，oflife，inwhatevergroupoflivingbeingsitmaybestudied.Butitwillbeunderstoodthatthisgeneraluniformitybynomeansexcludesanyamountofspecialmodificationsofthefundamentalsubstance.Themineral，carbonateoflime，assumesanimmensediversityofcharacters，thoughnoonedoubtsthat，underalltheseProteanchanges，itisoneandthesamething.
Andnow，whatistheultimatefate，andwhattheorigin，ofthematteroflife？
Isit，assomeoftheoldernaturalistssupposed，diffusedthroughouttheuniverseinmolecules，whichareindestructibleandunchangeableinthemselves;but，inendlesstransmigration，uniteininnumerablepermutations，intothediversifiedformsoflifeweknow？Or，isthematteroflifecomposedofordinarymatter，differingfromitonlyinthemannerinwhichitsatomsareaggregated？Isitbuiltupofordinarymatter，andagainresolvedintoordinarymatterwhenitsworkisdone？
Modernsciencedoesnothesitateamomentbetweenthesealternatives.Physiologywritesovertheportalsoflife——
"Debemurmortinosnostraque，"[102]
withaprofoundermeaningthantheRomanpoetattachedtothatmelancholyline.Underwhateverdisguiseittakesrefuge，whetherfungusoroak，wormorman，thelivingprotoplasmnotonlyultimatelydiesandisresolvedintoitsmineralandlifelessconstituents，butisalwaysdying，and，strangeastheparadoxmaysound，couldnotliveunlessitdied.
InthewonderfulstoryofthePeaudeChagrin，[103]theherobecomespossessedofamagicalwildass’skin，whichyieldshimthemeansofgratifyingallhiswishes.Butitssurfacerepresentsthedurationoftheproprietor’slife;andforeverysatisfieddesiretheskinshrinksinproportiontotheintensityoffruition，untilatlengthlifeandthelasthandbreadthofthepeaudechagrin，disappearwiththegratificationofalastwish.
Balzac’s[104]studieshadledhimoverawiderangeofthoughtandspeculation，andhisshadowingforthofphysiologicaltruthinthisstrangestorymayhavebeenintentional.Atanyrate，thematteroflifeisaveritablepeaudechagrin，andforeveryvitalactitissomewhatthesmaller.Allworkimplieswaste，andtheworkofliferesults，directlyorindirectly，inthewasteofprotoplasm.
Everywordutteredbyaspeakercostshimsomephysicalloss;and，inthestrictestsense，heburnsthatothersmayhavelight——somucheloquence，somuchofhisbodyresolvedintocarbonicacid，water，andurea.Itisclearthatthisprocessofexpenditurecannotgoonforever.But，happily，theprotoplasmicpeaudechagrindiffersfromBalzac’sinitscapacityofbeingrepaired，andbroughtbacktoitsfullsize，aftereveryexertion.
Forexample，thispresentlecture，whateveritsintellectualworthtoyou，hasacertainphysicalvaluetome，whichis，conceivably，expressiblebythenumberofgrainsofprotoplasmandotherbodilysubstancewastedinmaintainingmyvitalprocessesduringitsdelivery.Mypeaudechagrinwillbedistinctlysmallerattheendofthediscoursethanitwasatthebeginning.Byandby，Ishallprobablyhaverecoursetothesubstancecommonlycalledmutton，forthepurposeofstretchingitbacktoitsoriginalsize.Nowthismuttonwasoncethelivingprotoplasm，moreorlessmodified，ofanotheranimal——asheep.AsIshalleatit，itisthesamematteraltered，notonlybydeath，butbyexposuretosundryartificialoperationsintheprocessofcooking.
Butthesechanges，whateverbetheirextent，havenotrendereditincompetenttoresumeitsoldfunctionsasmatteroflife.A
singularinwardlaboratory，whichIpossess，willdissolveacertainportionofthemodifiedprotoplasm;thesolutionsoformedwillpassintomyveins;andthesubtleinfluencestowhichitwillthenbesubjectedwillconvertthedeadprotoplasmintolivingprotoplasm，andtransubstantiatesheepintoman.
Noristhisall.Ifdigestionwereathingtobetrifledwith，I
mightsupuponlobster，andthematteroflifeofthecrustaceanwouldundergothesamewonderfulmetamorphosisintohumanity.AndwereItoreturntomyownplacebysea，andundergoshipwreck，thecrustaceanmight，andprobablywould，returnthecompliment，anddemonstrateourcommonnaturebyturningmyprotoplasmintolivinglobster.Or，ifnothingbetterweretobehad，Imightsupplymywantswithmerebread，andIshouldfindtheprotoplasmofthewheat—planttobeconvertibleintoman，withnomoretroublethanthatofthesheep，andwithfarless，Ifancy，thanthatofthelobster.
Henceitappearstobeamatterofnogreatmomentwhatanimal，orwhatplant，Ilayundercontributionforprotoplasm，andthefactspeaksvolumesforthegeneralidentityofthatsubstanceinalllivingbeings.Isharethiscatholicityofassimilationwithotheranimals，allofwhich，sofarasweknow，couldthriveequallywellontheprotoplasmofanyoftheirfellows，orofanyplant;butheretheassimilativepowersoftheanimalworldcease.Asolutionofsmelling—saltsinwater，withaninfinitesimalproportionofsomeothersalinematters，containsalltheelementarybodieswhichenterintothecompositionofprotoplasm;but，asIneedhardlysay，ahogsheadofthatfluidwouldnotkeepahungrymanfromstarving，norwoulditsaveanyanimalwhateverfromalikefate.
Ananimalcannotmakeprotoplasm，butmusttakeitready—madefromsomeotheranimal，orsomeplant——theanimal’shighestfeatofconstructivechemistrybeingtoconvertdeadprotoplasmintothatlivingmatteroflifewhichisappropriatetoitself.