a history of science-4-第26章

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ld　find　among　them　not　one　who　acknowledged　a　doctrine　of　transmutation。　The　reaction　from　the　stand…point　of　Lamarck　and　Erasmus　Darwin　and　Goethe　had　been　complete；　and　when　Charles　Darwin　avowed　his　own　conviction　he　expected　always　to　have　it　met　with　ridicule　or　contempt。　In　1857　there　was　but　one　man　speaking　with　any　large　degree　of　authority　in　the　world　who　openly　avowed　a　belief　in　transmutation　of　speciesthat　man　being　Herbert　Spencer。　　But　the　Origin　of　Species　came；　as　Huxley　has　said；　like　a　flash　in　the　darkness；　enabling　the　benighted　voyager　to　see　the　way。　　The　score　of　years　during　which　its　author　had　waited　and　worked　had　been　years　well　spent。　　Darwin　had　become；　as　he　himself　says；　a　veritable　Croesus；　〃overwhelmed　with　his　riches　in　facts〃facts　of　zoology；　of　selective　artificial　breeding；　of　geographical　distribution　of　animals；　of　embryology；　of　paleontology。　He　had　massed　his　facts　about　his　theory；　condensed　them　and　recondensed；　until　his　volume　of　five　hundred　pages　was　an　encyclopaedia　in　scope。　During　those　long　years　of　musing　he　had　thought　out　almost　every　conceivable　objection　to　his　theory；　and　in　his　book　every　such　objection　was　stated　with　fullest　force　and　candor；　together　with　such　reply　as　the　facts　at　command　might　dictate。　It　was　the　force　of　those　twenty　years　of　effort　of　a　master…mind　that　made　the　sudden　breach　in　the　breaswtork｛sic｝　of　current　thought。

Once　this　breach　was　effected　the　work　of　conquest　went　rapidly　on。　Day　by　day　squads　of　the　enemy　capitulated　and　struck　their　arms。　By　the　time　another　score　of　years　had　passed　the　doctrine　of　evolution　had　become　the　working　hypothesis　of　the　scientific　world。　The　revolution　had　been　effected。

And　from　amid　the　wreckage　of　opinion　and　belief　stands　forth　the　figure　of　Charles　Darwin；　calm；　imperturbable；　serene；　scatheless　to　ridicule；　contumely；　abuse；　unspoiled　by　ultimate　success；　unsullied　alike　by　the　strife　and　the　victorytake　him　for　all　in　all；　for　character；　for　intellect；　for　what　he　was　and　what　he　did；　perhaps　the　most　Socratic　figure　of　the　century。　　When；　in　1882；　he　died；　friend　and　foe　alike　conceded　that　one　of　the　greatest　sons　of　men　had　rested　from　his　labors；　and　all　the　world　felt　it　fitting　that　the　remains　of　Charles　Darwin　should　be　entombed　in　Westminster　Abbey　close　beside　the　honored　grave　of　Isaac　Newton。　　Nor　were　there　many　who　would　dispute　the　justice　of　Huxley's　estimate　of　his　accomplishment：　〃He　found　a　great　truth　trodden　under　foot。　　Reviled　by　bigots；　and　ridiculed　by　all　the　world；　he　lived　long　enough　to　see　it；　chiefly　by　his　own　efforts；　irrefragably　established　in　science；　inseparably　incorporated　with　the　common　thoughts　of　men；　and　only　hated　and　feared　by　those　who　would　revile　but　dare　not。〃


THE　ORIGIN　OF　THE　FITTEST

Wide　as　are　the　implications　of　the　great　truth　which　Darwin　and　his　co…workers　established；　however；　it　leaves　quite　untouched　the　problem　of　the　origin　of　those　〃favored　variations〃　upon　which　it　operates。　That　such　variations　are　due　to　fixed　and　determinate　causes　no　one　understood　better　than　Darwin；　but　in　his　original　exposition　of　his　doctrine　he　made　no　assumption　as　to　what　these　causes　are。　He　accepted　the　observed　fact　of　variationas　constantly　witnessed；　for　example；　in　the　differences　between　parents　and　offspringand　went　ahead　from　this　assumption。

But　as　soon　as　the　validity　of　the　principle　of　natural　selection　came　to　be　acknowledged　speculators　began　to　search　for　the　explanation　of　those　variations　which；　for　purposes　of　argument；　had　been　provisionally　called　〃spontaneous。〃　Herbert　Spencer　had　all　along　dwelt　on　this　phase　of　the　subject；　expounding　the　Lamarckian　conceptions　of　the　direct　influence　of　the　environment　（an　idea　which　had　especially　appealed　to　Buffon　and　to　Geoffroy　Saint…Hilaire）；　and　of　effort　in　response　to　environment　and　stimulus　as　modifying　the　individual　organism；　and　thus　supplying　the　basis　for　the　operation　of　natural　selection。　Haeckel　also　became　an　advocate　of　this　idea；　and　presently　there　arose　a　so…called　school　of　neo…Lamarckians；　which　developed　particular　strength　and　prominence　in　America　under　the　leadership　of　Professors　A。　Hyatt　and　E。　D。　Cope。

But　just　as　the　tide　of　opinion　was　turning　strongly　in　this　direction；　an　utterly　unexpected　obstacle　appeared　in　the　form　of　the　theory　of　Professor　August　Weismann；　put　forward　in　1883；　which　antagonized　the　Lamarckian　conception　（though　not　touching　the　Darwinian；　of　which　Weismann　is　a　firm　upholder）　by　denying　that　individual　variations；　however　acquired　by　the　mature　organism；　are　transmissible。　The　flurry　which　this　denial　created　has　not　yet　altogether　subsided；　but　subsequent　observations　seem　to　show　that　it　was　quite　disproportionate　to　the　real　merits　of　the　case。　Notwithstanding　Professor　Weismann's　objections；　the　balance　of　evidence　appears　to　favor　the　view　that　the　Lamarckian　factor　of　acquired　variations　stands　as　the　complement　of　the　Darwinian　factor　of　natural　selection　in　effecting　the　transmutation　of　species。

Even　though　this　partial　explanation　of　what　Professor　Cope　calls　the　〃origin　of　the　fittest〃　be　accepted；　there　still　remains　one　great　life　problem　which　the　doctrine　of　evolution　does　not　touch。　The　origin　of　species；　genera；　orders；　and　classes　of　beings　through　endless　transmutations　is　in　a　sense　explained；　but　what　of　the　first　term　of　this　long　series？　　Whence　came　that　primordial　organism　whose　transmuted　descendants　make　up　the　existing　faunas　and　floras　of　the　globe？

There　was　a　time；　soon　after　the　doctrine　of　evolution　gained　a　hearing；　when　the　answer　to　that　question　seemed　to　some　scientists　of　authority　to　have　been　given　by　experiment。　Recurring　to　a　former　belief；　and　repeating　some　earlier　experiments；　the　director　of　the　Museum　of　Natural　History　at　Rouen；　M。　F。　A。　Pouchet；　reached　the　conclusion　that　organic　beings　are　spontaneously　generated　about　us　constantly；　in　the　familiar　processes　of　putrefaction；　which　were　known　to　be　due　to　the　agency　of　microscopic　bacteria。　But　in　1862　Louis　Pasteur　proved　that　this　seeming　spontaneous　generation　is　in　reality　due　to　the　existence　of　germs　in　the　air。　Notwithstanding　the　conclusiveness　of　these　experiments；　the　claims　of　Pouchet　were　revived　in　England　ten　years　later　by　Professor　Bastian；　but　then　the　experiments　of　John　Tyndall；　fully　corroborating　the　results　of　Pasteur；　gave　a　final　quietus　to　the　claim　of　〃spontaneous　generation〃　as　hitherto　formulated。

There　for　the　moment　the　matter　rests。　　But　the　end　is　not　yet。　Fauna　and　flora　are　here；　and；　thanks　to　Lamarck　and　Wallace　and　Darwin；　their　development；　through　the　operation　of　those　〃secondary　causes〃　which　we　call　laws　of　nature；　has　been　proximally　explained。　The　lowest　forms　of　life　have　been　linked　with　the　highest　in　unbroken　chains　of　descent。　　Meantime；　through　the　efforts　of　chemists　and　biologists；　the　gap　between　the　inorganic　and　the　organic　worlds；　which　once　seemed　almost　infinite；　has　been　constantly　narrowed。　Already　philosophy　can　throw　a　bridge　across　that　gap。　But　inductive　science；　which　builds　its　own　bridges；　has　not　yet　spanned　the　chasm；　small　though　it　appear。　　Until　it　shall　have　done　so；　the　bridge　of　organic　evolution　is　not　quite　complete；　yet　even　as　it　stands　to…day　it　is　perhaps　the　most　stupendous　scientific　structure　of　the　nineteenth　century。



VII。　EIGHTEENTH…CENTURY　MEDICINE

THE　SYSTEM　OF　BOERHAAVE

At　least　two　pupils　of　William　Harvey　distinguished　themselves　in　medicine；　Giorgio　Baglivi　（1669…1707）；　who　has　been　called　the　〃Italian　Sydenham；〃　and　Hermann　Boerhaave　（1668…1738）。　The　work　of　Baglivi　was　hardly　begun　before　his　early　death　removed　one　of　the　most　promising　of　the　early　eighteenth…century　physicians。　　Like　Boerhaave；　he　represents　a　type　of　skilled；　practical　clinitian　rather　than　the　abstract　scientist。　One　of　his　contributions　to　medical　literature　is　the　first　accurate　description　of　typhoid；　or；　as　he　calls　it；　mesenteric　fever。

If　for　nothing　else；　Boerhaave　must　always　be　remembered　as　the　teacher　of　Von　Haller；　but　in　his　own　day　he　was　the　widest　known　and　the　most　popular　teacher　in　the　medical　world。　　He　was　the　idol　of　his　pupils　at　Leyden；　who　flocked　to　his　lectures　in　such　numbers　that　it　became　necessary　to　〃tear　down　the　walls　of　Leyden　to　accommodate　them。〃　His　fame　extended　not　only　all　over　Europe　but　to　Asia；　North　America；　and　even　into　South　America。　　A　letter　sent　him　from　China　was　addressed　to　〃Boerhaave　in　Europe。〃　　His　teachings　represent　the　best　medical　knowledge　of　his　day；　a　high　standard　of　morality；　and　a　keen　appreciation　of　the　value　of　observation；　and　it　was　through　such　teachings　imparted　to　his　pupils　and　advanced　by　them；　rather　than　to　any　new　discoveries；　that　his　name　is　important　in　medical　history。　His　arrangement　and　classification　of　the　different　branches　of　medicine　are　interesting　as　representing　the　attitude　of　the　medical　profession　towards　these　various　branches　at　that　time。


〃In　the　first　place　we　consider　Life；　then　Health；　afterwards　Diseases；　and　lastly　their　several　Remedies。

〃Health　the　first　general　branch　of　Physic　in　our　Institutions　is　termed　Physiology；　or　the　Animal　Oeconomy；　demonstrating　the　several　Parts　of　the　human　Body；　with　their　Mechanism　and　Actions。

〃The　second　branch　of　Physic　is　called　Pathology；　treating　of　Diseases；　their　Differences；　Causes　and　Effects；　or　Symptoms；　by　which　the　human　Body　is　known　to　vary　from　its　healthy　state。

〃The　third　part　of　Physic　is　termed　Semiotica；　which　shows　the　Signs　distinguishing　between　sickness　and　Health；　Diseases　and　their　Causes　in　the　human　Body；　it　also　imports　the　State　and　Degrees　of　Health　and　Diseases；　and　presages　their　future　Events。

〃The　fourth　general　branch　of　Physic　is　termed　Hygiene；　or　Prophylaxis。

〃The　fifth　and　last　part　of　Physic　is　called　Therapeutica；　which　instructs　us　in　the　Nature；　Preparation　and　uses　of　the　Materia　Medica；　and　the　methods　of　applying　the　same；　in　order　to　cure　Diseases　and　restore　lost　Health。〃＇1＇

From　this　we　may　gather　that　his　general　view　of　medicine　was　not　unlike　that　taken　at　the　present　time。

Boerhaave's　doctrines　were　arranged　into　a　〃system〃　by　Friedrich　Hoffmann；　of　Halle　（1660…1742）；　this　system　having　the　merit　of　being　simple　and　more　easily　comprehended　than　many　others。　　In　this　system　forces　were　considered　inherent　in　matter；　being　expressed　as　mechanical　movements；　and　determined　by　mass；　number；　and　weight。　　Similarly；　forces　express　themselves　in　the　body　by　movement；　contraction；　and　relaxation；　etc。；　and　life　itself　is　movement；　〃particularly　movement　of　the　heart。〃　Life　and　death　are；　therefore；　mechanical　phenomena；　health　is　determined　by　regularly　recurring　movements；　and　disease　by　irregularity　of　them。　The　body　is　simply　a　large　hydraulic　machine；　controlled　by　〃the　aether〃　or　〃sensitive　soul；〃　and　the　chief　centre　of　this　soul　lies　in　the　medulla。

In　the　practical　application　of　medicines　to　diseases　Hoffman　used　simple　remedies；　frequently　with　happy　results；　for　whatever　the　medical　man's　theory　may　be　he　seldom　has　the　temerity　to　follow　it　out　logically；　and　use　the　remedies　indicated　by　his　theory　to　the　exclusion　of　lo