a history of science-4-第11章

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color　to　the　possibility　that　our　alleged　elements　are　really　compounds；　which　at　the　temperature　of　the　hottest　stars　may　be　decomposed　into　hydrogen；　the　latter　〃element〃　itself　being　also　doubtless　a　compound；　which　might　be　resolved　under　yet　more　trying　conditions。

Here；　then；　was　what　might　be　termed　direct　experimental　evidence　for　the　hypothesis　of　Prout。　　Unfortunately；　however；　it　is　evidence　of　a　kind　which　only　a　few　experts　are　competent　to　discussso　very　delicate　a　matter　is　the　spectral　analysis　of　the　stars。　What　is　still　more　unfortunate；　the　experts　do　not　agree　among　themselves　as　to　the　validity　of　Professor　Lockyer's　conclusions。　Some；　like　Professor　Crookes；　have　accepted　them　with　acclaim；　hailing　Lockyer　as　〃the　Darwin　of　the　inorganic　world；〃　while　others　have　sought　a　different　explanation　of　the　facts　he　brings　forward。　As　yet　it　cannot　be　said　that　the　controversy　has　been　brought　to　final　settlement。　　Still；　it　is　hardly　to　be　doubted　that　now；　since　the　periodic　law　has　seemed　to　join　hands　with　the　spectroscope；　a　belief　in　the　compound　nature　of　the　so…called　elements　is　rapidly　gaining　ground　among　chemists。　　More　and　more　general　becomes　the　belief　that　the　Daltonian　atom　is　really　a　compound　radical；　and　that　back　of　the　seeming　diversity　of　the　alleged　elements　is　a　single　form　of　primordial　matter。　　Indeed；　in　very　recent　months；　direct　experimental　evidence　for　this　view　has　at　last　come　to　hand；　through　the　study　of　radio…active　substances。　　In　a　later　chapter　we　shall　have　occasion　to　inquire　how　this　came　about。



IV。　ANATOMY　AND　PHYSIOLOGY　IN　THE　EIGHTEENTH　CENTURY

ALBRECHT　VON　HALLER

An　epoch　in　physiology　was　made　in　the　eighteenth　century　by　the　genius　and　efforts　of　Albrecht　von　Haller　（1708…1777）；　of　Berne；　who　is　perhaps　as　worthy　of　the　title　〃The　Great〃　as　any　philosopher　who　has　been　so　christened　by　his　contemporaries　since　the　time　of　Hippocrates。　　Celebrated　as　a　physician；　he　was　proficient　in　various　fields；　being　equally　famed　in　his　own　time　as　poet；　botanist；　and　statesman；　and　dividing　his　attention　between　art　and　science。

As　a　child　Haller　was　so　sickly　that　he　was　unable　to　amuse　himself　with　the　sports　and　games　common　to　boys　of　his　age；　and　so　passed　most　of　his　time　poring　over　books。　　When　ten　years　of　age　he　began　writing　poems　in　Latin　and　German；　and　at　fifteen　entered　the　University　of　Tubingen。　　At　seventeen　he　wrote　learned　articles　in　opposition　to　certain　accepted　doctrines；　and　at　nineteen　he　received　his　degree　of　doctor。　Soon　after　this　he　visited　England；　where　his　zeal　in　dissecting　brought　him　under　suspicion　of　grave…robbery；　which　suspicion　made　it　expedient　for　him　to　return　to　the　Continent。　　After　studying　botany　in　Basel　for　some　time　he　made　an　extended　botanical　journey　through　Switzerland；　finally　settling　in　his　native　city；　Berne；　as　a　practising　physician。　During　this　time　he　did　not　neglect　either　poetry　or　botany；　publishing　anonymously　a　collection　of　poems。

In　1736　he　was　called　to　Gottingen　as　professor　of　anatomy；　surgery；　chemistry；　and　botany。　　During　his　labors　in　the　university　he　never　neglected　his　literary　work；　sometimes　living　and　sleeping　for　days　and　nights　together　in　his　library；　eating　his　meals　while　delving　in　his　books；　and　sleeping　only　when　actually　compelled　to　do　so　by　fatigue。　During　all　this　time　he　was　in　correspondence　with　savants　from　all　over　the　world；　and　it　is　said　of　him　that　he　never　left　a　letter　of　any　kind　unanswered。

Haller's　greatest　contribution　to　medical　science　was　his　famous　doctrine　of　irritability；　which　has　given　him　the　name　of　〃father　of　modern　nervous　physiology；〃　just　as　Harvey　is　called　〃the　father　of　the　modern　physiology　of　the　blood。〃　It　has　been　said　of　this　famous　doctrine　of　irritability　that　〃it　moved　all　the　minds　of　the　centuryand　not　in　the　departments　of　medicine　alonein　a　way　of　which　we　of　the　present　day　have　no　satisfactory　conception；　unless　we　compare　it　with　our　modern　Darwinism。〃＇1＇

The　principle　of　general　irritability　had　been　laid　down　by　Francis　Glisson　（1597…1677）　from　deductive　studies；　but　Haller　proved　by　experiments　along　the　line　of　inductive　methods　that　this　irritability　was　not　common　to　all　〃fibre　as　well　as　to　the　fluids　of　the　body；〃　but　something　entirely　special；　and　peculiar　only　to　muscular　substance。　He　distinguished　between　irritability　of　muscles　and　sensibility　of　nerves。　In　1747　he　gave　as　the　three　forces　that　produce　muscular　movements：　elasticity；　or　〃dead　nervous　force〃；　irritability；　or　〃innate　nervous　force〃；　and　nervous　force　in　itself。　　And　in　1752　he　described　one　hundred　and　ninety　experiments　for　determining　what　parts　of　the　body　possess　〃irritability〃that　is；　the　property　of　contracting　when　stimulated。　His　conclusion　that　this　irritability　exists　in　muscular　substance　alone　and　is　quite　independent　of　the　nerves　proceeding　to　it　aroused　a　controversy　that　was　never　definitely　settled　until　late　in　the　nineteenth　century；　when　Haller's　theory　was　found　to　be　entirely　correct。

It　was　in　pursuit　of　experiments　to　establish　his　theory　of　irritability　that　Haller　made　his　chief　discoveries　in　embryology　and　development。　He　proved　that　in　the　process　of　incubation　of　the　egg　the　first　trace　of　the　heart　of　the　chick　shows　itself　in　the　thirty…eighth　hour；　and　that　the　first　trace　of　red　blood　showed　in　the　forty…first　hour。　By　his　investigations　upon　the　lower　animals　he　attempted　to　confirm　the　theory　that　since　the　creation　of　genus　every　individual　is　derived　from　a　preceding　individualthe　existing　theory　of　preformation；　in　which　he　believed；　and　which　taught　that　〃every　individual　is　fully　and　completely　preformed　in　the　germ；　simply　growing　from　microscopic　to　visible　proportions；　without　developing　any　new　parts。〃

In　physiology；　besides　his　studies　of　the　nervous　system；　Haller　studied　the　mechanism　of　respiration；　refuting　the　teachings　of　Hamberger　（1697…1755）；　who　maintained　that　the　lungs　contract　independently。　Haller；　however；　in　common　with　his　contemporaries；　failed　utterly　to　understand　the　true　function　of　the　lungs。　　The　great　physiologist's　influence　upon　practical　medicine；　while　most　profound；　was　largely　indirect。　He　was　a　theoretical　rather　than　a　practical　physician；　yet　he　is　credited　with　being　the　first　physician　to　use　the　watch　in　counting　the　pulse。


BATTISTA　MORGAGNI　AND　MORBID　ANATOMY

A　great　contemporary　of　Haller　was　Giovanni　Battista　Morgagni　（1682…1771）；　who　pursued　what　Sydenham　had　neglected；　the　investigation　in　anatomy；　thus　supplying　a　necessary　counterpart　to　the　great　Englishman's　work。　　Morgagni's　investigations　were　directed　chiefly　to　the　study　of　morbid　anatomythe　study　of　the　structure　of　diseased　tissue；　both　during　life　and　post　mortem；　in　contrast　to　the　normal　anatomical　structures。　This　work　cannot　be　said　to　have　originated　with　him；　for　as　early　as　1679　Bonnet　had　made　similar；　although　less　extensive；　studies；　and　later　many　investigators；　such　as　Lancisi　and　Haller；　had　made　post…mortem　studies。　　But　Morgagni's　De　sedibus　et　causis　morborum　per　anatomen　indagatis　was　the　largest；　most　accurate；　and　best…illustrated　collection　of　cases　that　had　ever　been　brought　together；　and　marks　an　epoch　in　medical　science。　From　the　time　of　the　publication　of　Morgagni's　researches；　morbid　anatomy　became　a　recognized　branch　of　the　medical　science；　and　the　effect　of　the　impetus　thus　given　it　has　been　steadily　increasing　since　that　time。


WILLIAM　HUNTER

William　Hunter　（1718…1783）　must　always　be　remembered　as　one　of　the　greatest　physicians　and　anatomists　of　the　eighteenth　century；　and　particularly　as　the　first　great　teacher　of　anatomy　in　England；　but　his　fame　has　been　somewhat　overshadowed　by　that　of　his　younger　brother　John。

Hunter　had　been　intended　and　educated　for　the　Church；　but　on　the　advice　of　the　surgeon　William　Cullen　he　turned　his　attention　to　the　study　of　medicine。　His　first　attempt　at　teaching　was　in　1746；　when　he　delivered　a　series　of　lectures　on　surgery　for　the　Society　of　Naval　Practitioners。　　These　lectures　proved　so　interesting　and　instructive　that　he　was　at　once　invited　to　give　others；　and　his　reputation　as　a　lecturer　was　soon　established。　He　was　a　natural　orator　and　story…teller；　and　he　combined　with　these　attractive　qualities　that　of　thoroughness　and　clearness　in　demonstrations；　and　although　his　lectures　were　two　hours　long　he　made　them　so　full　of　interest　that　his　pupils　seldom　tired　of　listening。　　He　believed　that　he　could　do　greater　good　to　the　world　by　〃publicly　teaching　his　art　than　by　practising　it；〃　and　even　during　the　last　few　days　of　his　life；　when　he　was　so　weak　that　his　friends　remonstrated　against　it；　he　continued　his　teaching；　fainting　from　exhaustion　at　the　end　of　his　last　lecture；　which　preceded　his　death　by　only　a　few　days。

For　many　years　it　was　Hunter's　ambition　to　establish　a　museum　where　the　study　of　anatomy；　surgery；　and　medicine　might　be　advanced；　and　in　1765　he　asked　for　a　grant　of　a　plot　of　ground　for　this　purpose；　offering　to　spend　seven　thousand　pounds　on　its；　erection　besides　endowing　it　with　a　professorship　of　anatomy。　Not　being　able　to　obtain　this　grant；　however；　he　built　a　house；　in　which　were　lecture　and　dissecting　rooms；　and　his　museum。　In　this　museum　were　anatomical　preparations；　coins；　minerals；　and　natural…history　specimens。

Hunter's　weakness　was　his　love　of　controversy　and　his　resentment　of　contradiction。　　This　brought　him　into　strained　relations　with　many　of　the　leading　physicians　of　his　time；　notably　his　own　brother　John；　who　himself　was　probably　not　entirely　free　from　blame　in　the　matter。　Hunter　is　said　to　have　excused　his　own　irritability　on　the　grounds　that　being　an　anatomist；　and　accustomed　to　〃the　passive　submission　of　dead　bodies；〃　contradictions　became　the　more　unbearable。　Many　of　the　physiological　researches　begun　by　him　were　carried　on　and　perfected　by　his　more　famous　brother；　particularly　his　investigations　of　the　capillaries；　but　he　added　much　to　the　anatomical　knowledge　of　several　structures　of　the　body；　notably　as　to　the　structure　of　cartilages　and　joints。


JOHN　HUNTER

In　Abbot　Islip's　chapel　in　Westminster　Abbey；　close　to　the　resting…place　of　Ben　Jonson；　rest　the　remains　of　John　Hunter　（1728…1793）；　famous　in　the　annals　of　medicine　as　among　the　greatest　physiologists　and　surgeons　that　the　world　has　ever　produced：　a　man　whose　discoveries　and　inventions　are　counted　by　scores；　and　whose　field　of　research　was　only　limited　by　the　outermost　boundaries　of　eighteenth…century　science；　although　his　efforts　were　directed　chiefly　along　the　lines　of　his　profession。

Until　about　twenty　years　of　age　young　Hunter　had　shown　little　aptitude　for　study；　being　unusually　fond　of　out…door　sports　and　amusements；　but　about　that　time；　realizing　that　some　occupation　must　be　selected；　he　asked　permission　of　his　brother　William　to　attempt　some　dissections　in　his　anatomical　school　in　London。　　To　the　surprise　of　his　brother　he　made　this　dissection　unusually　well；　and　being　given　a　second；　he　acquitted　himself　with　such　skill　that　his　brother　at　once　predicted　that　he　would　become　a　great　anatomist。　　Up　to　this　time　he　had　had　no　training　of　any　kind　to　prepare　him　for　his　professional　career；　and　knew　little　of