第24章

Severalcausesconspiredtomakeexplorationallthefashionduringtheclosingepochoftheeighteenthcentury。Newaidtothenavigatorhadbeenfurnishedbytheperfectedcompassandquadrant，andbytheinventionofthechronometer；medicalsciencehadbanishedscurvy，whichhithertohadbeenaperpetualmenacetothevoyager；and，aboveall，therestlessspiritoftheageimpelledtheventuresometoseeknoveltyinfieldsaltogethernew。Somestartedforthepole，otherstriedforanortheastornorthwestpassagetoIndia，yetotherssoughtthegreatfictitiousantarcticcontinenttoldofbytradition。Alltheseofcoursefailedoftheirimmediatepurpose，buttheyaddedmuchtotheworld’sstoreofknowledgeanditsfundoftravellers’tales。

Amongallthesetalesnonewasmoreremarkablethanthosewhichtoldofstrangelivingcreaturesfoundinantipodallands。Andhere，asdidnothappenineveryfield，thenarrativeswereoftensubstantiatedbytheexhibitionofspecimensthatadmittednoquestion。Manyacompanyofexplorersreturnedmoreorlessladenwithsuchtrophiesfromtheanimalandvegetablekingdoms，tothemingledastonishment，delight，andbewildermentoftheclosetnaturalists。ThefollowersofLinnaeusinthe"goldenageofnaturalhistory，"afewdecadesbefore，hadincreasedthenumberofknownspeciesoffishestoaboutfourhundred，ofbirdstoonethousand，ofinsectstothreethousand，andofplantstotenthousand。Butnowthesesuddenaccessionsfromnewterritoriesdoubledthefigureforplants，tripleditforfishandbirds，andbroughtthenumberofdescribedinsectsabovetwentythousand。

Naturallyenough，thiswealthofnewmaterialwassorelypuzzlingtotheclassifiers。ThemorediscerningbegantoseethattheartificialsystemofLinnaeus，wonderfulandusefulasithadbeen，mustbeadvanceduponbeforethenewmaterialcouldbesatisfactorilydisposedof。Thewaytoamorenaturalsystem，basedonlessarbitrarysigns，hadbeenpointedoutbyJussieuinbotany，butthezoologistswerenotpreparedtomakeheadwaytowardssuchasystemuntiltheyshouldgainawiderunderstandingoftheorganismswithwhichtheyhadtodealthroughcomprehensivestudiesofanatomy。Suchstudiesofindividualformsintheirrelationstotheentirescaleoforganicbeingswerepursuedintheselastdecadesofthecentury，butthoughtwoorthreemostimportantgeneralizationswereachieved(notablyKasparWolff’sconceptionofthecellasthebasisoforganiclife，andGoethe’sall-importantdoctrineofmetamorphosisofparts)，yet，asawhole，theworkoftheanatomistsoftheperiodwasgerminativeratherthanfruit-bearing。Bichat’svolumes，tellingoftherecognitionofthefundamentaltissuesofthebody，didnotbegintoappeartillthelastyearofthecentury。TheannouncementbyCuvierofthedoctrineofcorrelationofpartsbearsthesamedate，butingeneralthestudiesofthisgreatnaturalist，whichinduetimeweretostamphimasthesuccessorofLinnaeus，wereasyetonlyfairlybegun。

V。ANATOMYANDPHYSIOLOGYINTHENINETEENTHCENTURY

CUVIERANDTHECORRELATIONOFPARTS

WehaveseenthatthefocalpointsofthephysiologicalworldtowardsthecloseoftheeighteenthcenturywereItalyandEngland，butwhenSpallanzaniandHunterpassedawaythesceneshiftedtoFrance。Thetimewaspeculiarlypropitious，astherecentadvancesinmanylinesofsciencehadbroughtfreshdataforthestudentofanimallifewhichwereinneedofclassification，and，asseveralmindscapableofsuchataskwereinthefield，itwasnaturalthatgreatgeneralizationsshouldhavecometobequitethefashion。ThusitwasthatCuviercameforwardwithabrand-newclassificationoftheanimalkingdom，establishingfourgreattypesofbeing，whichhecalledvertebrates，mollusks，articulates，andradiates。Lamarckhadshortlybeforeestablishedthebroaddistinctionbetweenanimalswithandthosewithoutabackbone；Cuvier’sClassificationdividedthelatter——theinvertebrates——intothreeminorgroups。

Andthisdivision，familiareversincetoallstudentsofzoology，hasonlyinveryrecentyearsbeensupplanted，andthennotbyrevolution，butbyafurtherdivision，whichtheelaboraterecentstudiesoflowerformsoflifeseemedtomakedesirable。

Inthecourseofthosestudiesofcomparativeanatomywhichledtohisnewclassification，Cuvier’sattentionwascalledconstantlytothepeculiarco-ordinationofpartsineachindividualorganism。Thusananimalwithsharptalonsforcatchinglivingprey——asamemberofthecattribe——hasalsosharpteeth，adaptedfortearingupthefleshofitsvictim，andaparticulartypeofstomach，quitedifferentfromthatofherbivorouscreatures。Thisadaptationofallthepartsoftheanimaltooneanotherextendstothemostdiversepartsoftheorganism，andenablestheskilledanatomist，fromtheobservationofasingletypicalpart，todrawinferencesastothestructureoftheentireanimal——afactwhichwasofvastaidtoCuvierinhisstudiesofpaleontology。ItdidnotenableCuvier，nordoesitenableanyoneelse，toreconstructfullytheextinctanimalfromobservationofasinglebone，ashassometimesbeenasserted，butwhatitreallydoesestablish，inthehandsofanexpert，issufficientlyastonishing。

"Whilethestudyofthefossilremainsofthegreaterquadrupedsismoresatisfactory，"hewrites，"bytheclearresultswhichitaffords，thanthatoftheremainsofotheranimalsfoundinafossilstate，itisalsocomplicatedwithgreaterandmorenumerousdifficulties。Fossilshellsareusuallyfoundquiteentire，andretainingallthecharactersrequisiteforcomparingthemwiththespecimenscontainedincollectionsofnaturalhistory，orrepresentedintheworksofnaturalists。Eventheskeletonsoffishesarefoundmoreorlessentire，sothatthegeneralformsoftheirbodiescan，forthemostpart，beascertained，andusually，atleast，theirgenericandspecificcharactersaredeterminable，asthesearemostlydrawnfromtheirsolidparts。Inquadrupeds，onthecontrary，evenwhentheirentireskeletonsarefound，thereisgreatdifficultyindiscoveringtheirdistinguishingcharacters，asthesearechieflyfoundedupontheirhairsandcolorsandothermarkswhichhavedisappearedprevioustotheirincrustation。Itisalsoveryraretofindanyfossilskeletonsofquadrupedsinanydegreeapproachingtoacompletestate，asthestrataforthemostpartonlycontainseparatebones，scatteredconfusedlyandalmostalwaysbrokenandreducedtofragments，whicharetheonlymeanslefttonaturalistsforascertainingthespeciesorgeneratowhichtheyhavebelonged。

"Fortunatelycomparativeanatomy，whenthoroughlyunderstood，enablesustosurmountallthesedifficulties，asacarefulapplicationofitsprinciplesinstructsusinthecorrespondencesanddissimilaritiesoftheformsoforganizedbodiesofdifferentkinds，bywhicheachmayberigorouslyascertainedfromalmosteveryfragmentofitsvariouspartsandorgans。

"Everyorganizedindividualformsanentiresystemofitsown，allthepartsofwhichnaturallycorrespond，andconcurtoproduceacertaindefinitepurpose，byreciprocalreaction，orbycombiningtowardsthesameend。Hencenoneoftheseseparatepartscanchangetheirformswithoutacorrespondingchangeintheotherpartsofthesameanimal，andconsequentlyeachoftheseparts，takenseparately，indicatesalltheotherpartstowhichithasbelonged。Thus，asIhaveelsewhereshown，ifthevisceraofananimalaresoorganizedasonlytobefittedforthedigestionofrecentflesh，itisalsorequisitethatthejawsshouldbesoconstructedastofitthemfordevouringprey；theclawsmustbeconstructedforseizingandtearingittopieces；

theteethforcuttinganddividingitsflesh；theentiresystemofthelimbs，ororgansofmotion，forpursuingandovertakingit；andtheorgansofsensefordiscoveringitatadistance。

Naturemustalsohaveendowedthebrainoftheanimalwithinstinctssufficientforconcealingitselfandforlayingplanstocatchitsnecessaryvictims……

"Toenabletheanimaltocarryoffitspreywhenseized，acorrespondingforceisrequisiteinthemuscleswhichelevatethehead，andthisnecessarilygivesrisetoadeterminateformofthevertebraetowhichthesemusclesareattachedandoftheocciputintowhichtheyareinserted。Inorderthattheteethofacarnivorousanimalmaybeabletocuttheflesh，theyrequiretobesharp，moreorlesssoinproportiontothegreaterorlessquantityoffleshthattheyhavetocut。Itisrequisitethattheirrootsshouldbesolidandstrong，inproportiontothequantityandsizeoftheboneswhichtheyhavetobreaktopieces。Thewholeofthesecircumstancesmustnecessarilyinfluencethedevelopmentandformofallthepartswhichcontributetomovethejaws……

Aftertheseobservations，itwillbeeasilyseenthatsimilarconclusionsmaybedrawnwithrespecttothelimbsofcarnivorousanimals，whichrequireparticularconformationstofitthemforrapidityofmotioningeneral；andthatsimilarconsiderationsmustinfluencetheformsandconnectionsofthevertebraeandotherbonesconstitutingthetrunkofthebody，tofitthemforflexibilityandreadinessofmotioninalldirections。Thebonesalsoofthenose，oftheorbit，andoftheearsrequirecertainformsandstructurestofitthemforgivingperfectiontothesensesofsmell，sight，andhearing，sonecessarytoanimalsofprey。Inshort，theshapeandstructureoftheteethregulatetheformsofthecondyle，oftheshoulder-blade，andoftheclaws，inthesamemannerastheequationofacurveregulatesallitsotherproperties；andasinregardtoanyparticularcurveallitspropertiesmaybeascertainedbyassumingeachseparatepropertyasthefoundationofaparticularequation，inthesamemanneraclaw，ashoulder-blade，acondyle，alegorarmbone，oranyotherboneseparatelyconsidered，enablesustodiscoverthedescriptionofteethtowhichtheyhavebelonged；andsoalsoreciprocallywemaydeterminetheformsoftheotherbonesfromtheteeth。Thuscommencingourinvestigationsbyacarefulsurveyofanyonebonebyitself，apersonwhoissufficientlymasterofthelawsoforganicstructuremay，asitwere，reconstructthewholeanimaltowhichthatbonebelonged。"[1]

Wehavealreadypointedoutthatnooneisquiteabletoperformthenecromanticfeatsuggestedinthelastsentence；buttheexaggerationispardonableintheenthusiasttowhomtheprinciplemeantsomuchandinwhosehandsitextendedsofar。

Ofcoursethisentireprinciple，initsbroadoutlines，issomethingwithwhicheverystudentofanatomyhadbeenfamiliarfromthetimewhenanatomywasfirststudied，butthefullexpressionofthe"lawofco-ordination，"asCuviercalledit，hadneverbeenexplicitlymadebefore；and，notwithstandingitsseemingobviousness，theexpositionwhichCuviermadeofitintheintroductiontohisclassicalworkoncomparativeanatomy，whichwaspublishedduringthefirstdecadeofthenineteenthcentury，ranksasagreatdiscovery。Itisoneofthosegeneralizationswhichserveasguidepoststootherdiscoveries。

BICHATANDTHEBODILYTISSUES

Muchthesamethingmaybesaidofanothergeneralizationregardingtheanimalbody，whichthebrilliantyoungFrenchphysicianMarieFrancoisBichatmadeincallingattentiontothefactthateachvertebrateorganism，includingman，hasreallytwoquitedifferentsetsoforgans——onesetundervolitionalcontrol，andservingtheendoflocomotion，theotherremovedfromvolitionalcontrol，andservingtheendsofthe"vitalprocesses"

ofdigestion，assimilation，andthelike。Hecalledthesesetsoforganstheanimalsystemandtheorganicsystem，respectively。

Thedivisionthuspointedoutwasnotquitenew，forGrimaud，professorofphysiologyintheUniversityofMontpellier，hadearliermadewhatwassubstantiallythesameclassificationofthefunctionsinto"internalordigestiveandexternalorlocomotive"；butitwasBichat’sexpositionthatgavecurrencytotheidea。

Farmoreimportant，however，wasanotherclassificationwhichBichatputforwardinhisworkonanatomy，publishedjustatthebeginningofthelastcentury。ThiswasthedivisionofallanimalstructuresintowhatBichatcalledtissues，andthepointingoutthattherearereallyonlyafewkindsoftheseinthebody，makingupallthediverseorgans。Thusmuscularorgansformonesystem；membranousorgansanother；glandularorgansathird；thevascularmechanismafourth，andsoon。Thedistinctionissoobviousthatitseemsratherdifficulttoconceivethatitcouldhavebeenoverlookedbytheearliestanatomists；but，inpointoffact，itisonlyobviousbecausenowithasbeenfamiliarlytaughtforalmostacentury。IthadneverbeengivenexplicitexpressionbeforethetimeofBichat，thoughitissaidthatBichathimselfwassomewhatindebtedforittohismaster，Desault，andtothefamousalienistPinel。

Howeverthatmaybe，itiscertainthatallsubsequentanatomistshavefoundBichat’sclassificationofthetissuesoftheutmostvalueintheirstudiesoftheanimalfunctions。SubsequentadvancesweretoshowthatthedistinctionbetweenthevarioustissuesisnotreallysofundamentalasBichatsupposed，butthattakesnothingfromthepracticalvalueofthefamousclassification。

Itwasbutastepfromthisscientificclassificationoftissuestoasimilarclassificationofthediseasesaffectingthem，andthiswasoneofthegreateststepstowardsplacingmedicineontheplaneofanexactscience。ThissubjectofthesebranchescompletelyfascinatedBichat，andheexclaimed，enthusiastically:

"Takeawaysomefeversandnervoustrouble，andallelsebelongstothekingdomofpathologicalanatomy。"Butoutofthisenthusiasmcamegreatresults。Bichatpractisedashepreached，and，believingthatitwasonlypossibletounderstanddiseasebyobservingthesymptomscarefullyatthebedside，and，ifthediseaseterminatedfatally，bypost-mortemexamination，hewassoarduousinhispursuitofknowledgethatwithinaperiodoflessthansixmonthshehadmadeoversixhundredautopsies——arecordthathasseldom，ifever，beenequalled。Norwerehiseffortsfruitless，asasingleexamplewillsufficetoshow。Byhisexaminationshewasabletoprovethatdiseasesofthechest，whichhadformerlybeenclassedundertheindefinitename"peripneumonia，"mightinvolvethreedifferentstructures，thepleuralsaccoveringthelungs，thelungitself，andthebronchialtubes，thediseasesaffectingtheseorgansbeingknownrespectivelyaspleuritis，pneumonia，andbronchitis，eachonedifferingfromtheothersastoprognosisandtreatment。Theadvantageofsuchanexactclassificationneedsnodemonstration。

LISTERANDTHEPERFECTEDMICROSCOPE

Atthesametimewhenthesebroadmacroscopicaldistinctionswerebeingdrawntherewereotherworkerswhowerestrivingtogoevendeeperintotheintricaciesoftheanimalmechanismwiththeaidofthemicroscope。Thisundertaking，however，wasbesetwithverygreatopticaldifficulties，andforalongtimelittleadvancewasmadeupontheworkofprecedinggenerations。Twogreatopticalbarriers，knowntechnicallyassphericalandchromaticaberration——theoneduetoafailureoftheraysoflighttofallallinoneplanewhenfocalizedthroughalens，theotherduetothedispersiveactionofthelensinbreakingthewhitelightintoprismaticcolors——confrontedthemakersofmicroscopiclenses，andseemedallbutinsuperable。Themakingofachromaticlensesfortelescopeshadbeenaccomplished，itistrue，byDollandinthepreviouscentury，bytheunionoflensesofcrownglasswiththoseofflintglass，thesetwomaterialshavingdifferentindicesofrefractionanddispersion。But，asidefromthemechanicaldifficultieswhicharisewhenthelensisoftheminutedimensionsrequiredforusewiththemicroscope，otherperplexitiesareintroducedbythefactthattheuseofawidepenciloflightisadesideratum，inordertogainsufficientilluminationwhenlargemagnificationistobesecured。

Intheattempttoovercomethosedifficulties，theforemostphysicalphilosophersofthetimecametotheaidofthebestopticians。Veryearlyinthecentury，Dr。(afterwardsSirDavid)

Brewster，therenownedScotchphysicist，suggestedthatcertainadvantagesmightaccruefromtheuseofsuchgemsashavehighrefractiveandlowdispersiveindices，inplaceoflensesmadeofglass。Accordinglylensesweremadeofdiamond，ofsapphire，andsoon，andwithsomemeasureofsuccess。Butin1812amuchmoreimportantinnovationwasintroducedbyDr。WilliamHydeWollaston，oneofthegreatestandmostversatile，and，sincethedeathofCavendish，byfarthemosteccentricofEnglishnaturalphilosophers。Thiswasthesuggestiontousetwoplano-convexlenses，placedataprescribeddistanceapart，inlieuofthesingledouble-convexlensgenerallyused。Thiscombinationlargelyovercamethesphericalaberration，anditgainedimmediatefameasthe"Wollastondoublet。"

Toobviatelossoflightinsuchadoubletfromincreaseofreflectingsurfaces，Dr。Brewstersuggestedfillingtheinterspacebetweenthetwolenseswithacementhavingthesameindexofrefractionasthelensesthemselves——animprovementofmanifestadvantage。AnimprovementyetmoreimportantwasmadebyDr。Wollastonhimselfintheintroductionofthediaphragmtolimitthefieldofvisionbetweenthelenses，insteadofinfrontoftheanteriorlens。ApairoflensesthusequippedDr。

Wollastoncalledtheperiscopicmicroscope。Dr。Brewstersuggestedthatinsuchalensthesameobjectmightbeattainedwithgreatereasebygrindinganequatorialgrooveaboutathickorglobularlensandfillingthegroovewithanopaquecement。

Thisarrangementfoundmuchfavor，andcamesubsequentlytobeknownasaCoddingtonlens，thoughMr。Coddingtonlaidnoclaimtobeingitsinventor。

SirJohnHerschel，anotheroftheverygreatphysicistsofthetime，alsogaveattentiontotheproblemofimprovingthemicroscope，andin1821heintroducedwhatwascalledanaplanaticcombinationoflenses，inwhich，asthenameimplies，thesphericalaberrationwaslargelydoneawaywith。ItwasthoughtthattheuseofthisHerschelaplanaticcombinationasaneyepiece，combinedwiththeWollastondoubletfortheobjective，cameasnearperfectionasthecompoundmicroscopewaslikelysoontocome。Butinrealitytheinstrumentthusconstructed，thoughdoubtlesssuperiortoanypredecessor，wassodefectivethatforpracticalpurposesthesimplemicroscope，suchasthedoubletortheCoddington，waspreferabletothemorecomplicatedone。

Manyopticians，indeed，quitedespairedofeverbeingabletomakeasatisfactoryrefractingcompoundmicroscope，andsomeofthemhadtakenupanewSirIsaacNewton’ssuggestioninreferencetoareflectingmicroscope。Inparticular，ProfessorGiovanniBattistaAmici，averyfamousmathematicianandpracticalopticianofModena，succeededinconstructingareflectingmicroscopewhichwassaidtobesuperiortoanycompoundmicroscopeofthetime，thoughtheeventsoftheensuingyearsweredestinedtorobitofallbuthistoricalvalue。Fortherewereothers，fortunately，whodidnotdespairofthepossibilitiesoftherefractingmicroscope，andtheireffortsweredestinedbeforelongtobecrownedwithadegreeofsuccessnotevendreamedofbyanyprecedinggeneration。

ThemantowhomchiefcreditisduefordirectingthosefinalstepsthatmadethecompoundmicroscopeapracticalimplementinsteadofascientifictoywastheEnglishamateuropticianJosephJacksonLister。Combiningmathematicalknowledgewithmechanicalingenuity，andhavingthepracticalaidofthecelebratedopticianTulley，hedevisedformulaeforthecombinationoflensesofcrownglasswithothersofflintglass，soadjustedthattherefractiveerrorsofonewerecorrectedorcompensatedbytheother，withtheresultofproducinglensesofhithertounequalledpowersofdefinition；lensescapableofshowinganimagehighlymagnified，yetrelativelyfreefromthosedistortionsandfringesofcolorthathadheretoforebeensodisastroustotrueinterpretationofmagnifiedstructures。

Listerhadbegunhisstudiesofthelensin1824，butitwasnotuntil1830thathecontributedtotheRoyalSocietythefamouspaperdetailinghistheoriesandexperiments。Soonafterthisvariouscontinentalopticianswhohadlongbeenworkingalongsimilarlinestookthematterup，andtheirexpositions，inparticularthatofAmici，introducedtheimprovedcompoundmicroscopetotheattentionofmicroscopistseverywhere。Anditrequiredbutthemostcasualtrialtoconvincetheexperiencedobserversthatanewimplementofscientificresearchhadbeenplacedintheirhandswhichcarriedthemalongstepnearertheobservationoftheintimatephysicalprocesseswhichlieatthefoundationofvitalphenomena。Forthephysiologistthisperfectionofthecompoundmicroscopehadthesamesignificancethatthe，discoveryofAmericahadforthefifteenth-centurygeographers——itpromisedaveritableworldofutterlynovelrevelations。Norwasthefulfilmentofthatpromiselongdelayed。

Indeed，sonumerousandsoimportantwerethediscoveriesnowmadeintherealmofminuteanatomythattheriseofhistologytotherankofanindependentsciencemaybesaidtodatefromthisperiod。Hitherto，eversincethediscoveryofmagnifying-glasses，therehadbeenhereandthereaman，suchasLeuwenhoekorMalpighi，giftedwithexceptionalvision，andperhapsunusuallyhappyinhisconjectures，whomadeimportantcontributionstotheknowledgeoftheminutestructureoforganictissues；butnowofasuddenitbecamepossiblefortheveriesttyrotoconfirmorrefutethelaboriousobservationsofthesepioneers，whiletheskilledobservercouldstepeasilybeyondthebarriersofvisionthathithertowerequiteimpassable。Andso，naturallyenough，thephysiologistsofthefourthdecadeofthenineteenthcenturyrushedaseagerlyintothenewrealmofthemicroscopeas，forexample，theirsuccessorsofto-dayareexploringtherealmoftheX-ray。

Listerhimself，whohadbecomeaneagerinterrogatoroftheinstrumenthehadperfected，mademanyimportantdiscoveries，themostnotablebeinghisfinalsettlementofthelong-mootedquestionastothetrueformoftheredcorpusclesofthehumanblood。Inreality，aseverybodyknowsnowadays，thesearebiconcavedisks，butowingtotheirpeculiarfigureitiseasilypossibletomisinterprettheappearancestheypresentwhenseenthroughapoorlens，andthoughDr。ThomasYoungandvariousotherobservershadcomeverynearthetruthregardingthem，unanimityofopinionwaspossibleonlyaftertheverdictoftheperfectedmicroscopewasgiven。

Thesebloodcorpusclesaresoinfinitesimalinsizethatsomethinglikefivemillionsofthemarefoundineachcubicmillimetreoftheblood，yettheyareisolatedparticles，eachhaving，sotospeak，itsownpersonality。This，ofcourse，hadbeenknowntomicroscopistssincethedaysoftheearliestlenses。Ithadbeennoticed，too，byhereandthereanobserver，thatcertainofthesolidtissuesseemedtopresentsomethingofagranulartexture，asifthey，too，intheirultimateconstitution，weremadeupofparticles。Andnow，asbetterandbetterlenseswereconstructed，thisideagainedgroundconstantly，thoughforatimenoonesawitsfullsignificance。

Inthecaseofvegetabletissues，indeed，thefactthatlittleparticlesencasedamembranouscovering，andcalledcells，aretheultimatevisibleunitsofstructurehadlongbeenknown。Butitwassupposedthatanimaltissuesdifferedradicallyfromthisconstruction。Theelementaryparticlesofvegetables"wereregardedtoacertainextentasindividualswhichcomposedtheentireplant，while，ontheotherhand，nosuchviewwastakenoftheelementarypartsofanimals。"

ROBERTBROWNANDTHECELLNUCLEUS

Intheyear1833afurtherinsightintothenatureoftheultimateparticlesofplantswasgainedthroughtheobservationoftheEnglishmicroscopistRobertBrown，who，inthecourseofhismicroscopicstudiesoftheepidermisoforchids，discoveredinthecells"anopaquespot，"whichhenamedthenucleus。

Doubtlessthesame"spot"hadbeenseenoftenenoughbeforebyotherobservers，butBrownwasthefirsttorecognizeitasacomponentpartofthevegetablecellandtogiveitaname。

"IshallconcludemyobservationsonOrchideae，"saidBrown，"withanoticeofsomepointsoftheirgeneralstructure，whichchieflyrelatetothecellulartissue。Ineachcelloftheepidermisofagreatpartofthisfamil