time　when　the　mania　of　hypothesis　was　at　its　height；　and　when　the　practical　part　of　his　art　was　overrun　and　stultified　by　vile　and　silly　nostrums〃　（〃Horae　Subsecivae；〃　Vol。　I；　4th　ed。；　Edinburgh；　1882；　p。　40）。
  Listen　to　what　he　says　upon　the　method　of　the　study　of　medicine：　〃In　writing　therefore；　such　a　natural　history　of　diseases；　every　merely　philosophical　hypothesis　should　be　set　aside；　and　the　manifest　and　natural　phenomena；　however　minute；　should　be　noted　with　the　utmost　exactness。　　The　usefulness　of　this　procedure　cannot　be　easily　overrated；　as　compared　with　the　subtle　inquiries　and　trifling　notions　of　modern　writers；　for　can　there　be　a　shorter；　or　indeed　any　other　way　of　coming　at　the　morbific　causes；　or　discovering　the　curative　indications　than　by　a　certain　perception　of　the　peculiar　symptoms？　By　these　steps　and　helps　it　was　that　the　father　of　physic；　the　great　Hippocrates；　came　to　excel；　his　theory　being　no　more　than　an　exact　description　or　view　of　nature。　He　found　that　nature　alone　often　terminates　diseases；　and　works　a　cure　with　a　few　simple　medicines；　and　often　enough　with　no　medicines　at　all。〃
  Towards　the　end　of　the　century　many　great　clinical　teachers　arose；　of　whom　perhaps　the　most　famous　was　Boerhaave；　often　spoken　of　as　the　Dutch　Hippocrates；　who　inspired　a　group　of　distinguished　students。　I　have　already　referred　to　the　fact　that　Franciscus　Sylvius　at　Leyden　was　the　first　among　the　moderns　to　organize　systematic　clinical　teaching。　Under　Boerhaave；　this　was　so　developed　that　to　this　Dutch　university　students　flocked　from　all　parts　of　Europe。　　After　teaching　botany　and　chemistry；　Boerhaave　succeeded　to　the　chair　of　physic　in　1714。　With　an　unusually　wide　general　training；　a　profound　knowledge　of　the　chemistry　of　the　day　and　an　accurate　acquaintance　with　all　aspects　of　the　history　of　the　profession；　he　had　a　strongly　objective　attitude　of　mind　towards　disease；　following　closely　the　methods　of　Hippocrates　and　Sydenham。　　He　adopted　no　special　system；　but　studied　disease　as　one　of　the　phenomena　of　nature。　His　clinical　lectures；　held　bi…weekly；　became　exceedingly　popular　and　were　made　attractive　not　less　by　the　accuracy　and　care　with　which　the　cases　were　studied　than　by　the　freedom　from　fanciful　doctrines　and　the　frank　honesty　of　the　man。　　He　was　much　greater　than　his　published　work　would　indicate；　and；　as　is　the　case　with　many　teachers　of　the　first　rank；　his　greatest　contributions　were　his　pupils。　No　other　teacher　of　modern　times　has　had　such　a　following。　Among　his　favorite　pupils　may　be　mentioned　Haller；　the　physiologist；　and　van　Swieten　and　de　Haen；　the　founders　of　the　Vienna　school。
  In　Italy；　too；　there　were　men　who　caught　the　new　spirit；　and　appreciated　the　value　of　combining　morbid　anatomy　with　clinical　medicine。　Lancisi；　one　of　the　early　students　of　disease　of　the　heart；　left　an　excellent　monograph　on　the　subject；　and　was　the　first　to　call　special　attention　to　the　association　of　syphilis　with　cardio…vascular　disease。　A　younger　contemporary　of　his　at　Rome；　Baglivi；　was　unceasing　in　his　call　to　the　profession　to　return　to　Hippocratic　methods；　to　stop　reading　philosophical　theories　and　to　give　up　what　he　calls　the　〃fatal　itch〃　to　make　systems。
  The　Leyden　methods　of　instruction　were　carried　far　and　wide　throughout　Europe；　into　Edinburgh　by　John　Rutherford；　who　began　to　teach　at　the　Royal　Infirmary　in　1747；　and　was　followed　by　Whytt　and　by　Cullen；　into　England　by　William　Saunders　of　Guy's　Hospital。　　Unfortunately　the　great　majority　of　clinicians　could　not　get　away　from　the　theoretical　conceptions　of　disease；　and　Cullen's　theory　of　spasm　and　atony　exercised　a　profound　influence　on　practice；　particularly　in　this　country；　where　it　had　the　warm　advocacy　of　Benjamin　Rush。　　Even　more　widespread　became　the　theories　of　a　pupil　of　Cullen's；　John　Brown；　who　regarded　excitability　as　the　fundamental　property　of　all　living　creatures：　too　much　of　this　excitability　produced　what　were　known　as　sthenic　maladies；　too　little；　asthenic；　on　which　principles　practice　was　plain　enough。　Few　systems　of　medicine　have　ever　stirred　such　bitter　controversy；　particularly　on　the　Continent；　and　in　Charles　Creighton's　account　of　Brown＇7＇　we　read　that　as　late　as　1802　the　University　of　Gottingen　was　so　convulsed　by　controversies　as　to　the　merits　of　the　Brunonian　system　that　contending　factions　of　students　in　enormous　numbers；　not　unaided　by　the　professors；　met　in　combat　in　the　streets　on　two　consecutive　days　and　had　to　be　dispersed　by　a　troop　of　Hanoverian　horse。
  ＇7＇　Dictionary　of　National　Biography；　London；　1886；　VII；　14…17。
  But　the　man　who　combined　the　qualities　of　Vesalius；　Harvey　and　Morgagni　in　an　extraordinary　personality　was　John　Hunter。　　He　was；　in　the　first　place；　a　naturalist　to　whom　pathological　processes　were　only　a　small　part　of　a　stupendous　whole；　governed　by　law；　which；　however；　could　never　be　understood　until　the　facts　had　been　accumulated；　tabulated　and　systematized。　By　his　example；　by　his　prodigious　industry；　and　by　his　suggestive　experiments　he　led　men　again　into　the　old　paths　of　Aristotle；　Galen　and　Harvey。　He　made　all　thinking　physicians　naturalists；　and　he　lent　a　dignity　to　the　study　of　organic　life；　and　re…established　a　close　union　between　medicine　and　the　natural　sciences。　　Both　in　Britain　and　Greater　Britain；　he　laid　the　foundation　of　the　great　collections　and　museums；　particularly　those　connected　with　the　medical　schools。　The　Wistar…Horner　and　the　Warren　Museums　in　this　country　originated　with　men　greatly　influenced　by　Hunter。　　He　was；　moreover；　the　intellectual　father　of　that　interesting　group　of　men　on　this　side　of　the　Atlantic　who；　while　practising　as　physicians；　devoted　much　time　and　labor　to　the　study　of　natural　history；　such　men　as　Benjamin　Smith　Barton；　David　Hossack；　Jacob　Bigelow；　Richard　Harlan；　John　D。　Godman；　Samuel　George　Morton；　John　Collins　Warren；　Samuel　L。　Mitchill　and　J。　Ailken　Meigs。　　He　gave　an　immense　impetus　in　Great　Britain　to　the　study　of　morbid　anatomy；　and　his　nephew；　Matthew　Baillie；　published　the　first　important　book　on　the　subject　in　the　English　language。
  Before　the　eighteenth　century　closed　practical　medicine　had　made　great　advance。　　Smallpox；　though　not　one　of　the　great　scourges　like　plague　or　cholera；　was　a　prevalent　and　much　dreaded　disease；　and　in　civilized　countries　few　reached　adult　life　without　an　attack。　Edward　Jenner；　a　practitioner　in　Gloucestershire；　and　the　pupil　to　whom　John　Hunter　gave　the　famous　advice：　　〃Don't　think；　try！〃　had　noticed　that　milkmaids　who　had　been　infected　with　cowpox　from　the　udder　of　the　cow　were　insusceptible　to　smallpox。　I　show　you　here　the　hand　of　Sarah　Nelmes　with　cowpox；　1796。　A　vague　notion　had　prevailed　among　the　dairies　from　time　immemorial　that　this　disease　was　a　preventive　of　the　smallpox。　　Jenner　put　the　matter　to　the　test　of　experiment。　　Let　me　quote　here　his　own　words：　〃The　first　experiment　was　made　upon　a　lad　of　the　name　of　Phipps；　in　whose　arm　a　little　vaccine　virus　was　inserted；　taken　from　the　hand　of　a　young　woman　who　had　been　accidentally　infected　by　a　cow。　　Notwithstanding　the　resemblance　which　the　pustule；　thus　excited　on　the　boy's　arm；　bore　to　variolous　inoculation；　yet　as　the　indisposition　attending　it　was　barely　perceptible；　I　could　scarcely　persuade　myself　the　patient　was　secure　from　the　Small　Pox。　　However；　on　his　being　inoculated　some　months　afterwards；　it　proved　that　he　was　secure。〃＇8＇　The　results　of　his　experiments　were　published　in　a　famous　small　quarto　volume　in　1798。＇*＇　From　this　date；　smallpox　has　been　under　control。　Thanks　to　Jenner；　not　a　single　person　in　this　audience　is　pockmarked！　A　hundred　and　twenty…five　years　ago；　the　faces　of　more　than　half　of　you　would　have　been　scarred。　　We　now　know　the　principle　upon　which　protection　is　secured：　　an　active　acquired　immunity　follows　upon　an　attack　of　a　disease　of　a　similar　nature。　Smallpox　and　cowpox　are　closely　allied　and　the　substances　formed　in　the　blood　by　the　one　are　resistant　to　the　virus　of　the　other。　I　do　not　see　how　any　reasonable　person　can　oppose　vaccination　or　decry　its　benefits。　I　show　you　the　mortality　figures＇9＇　of　the　Prussian　Army　and　of　the　German　Empire。　　A　comparison　with　the　statistics　of　the　armies　of　other　European　countries　in　which　revaccination　is　not　so　thoroughly　carried　out　is　most　convincing　of　its　efficacy。
  ＇8＇　Edward　Jenner：　　The　Origin　of　the　Vaccine　Inoculation；　London；　1801。
  ＇*＇　Reprinted　by　Camac：　　Epoch…making　Contributions　to　Medicine；　etc。；　1909。Ed。
  ＇9＇　Jockmann：　　Pocken　und　Vaccinationlehre；　1913。
  The　early　years　of　the　century　saw　the　rise　of　modern　clinical　medicine　in　Paris。　　In　the　art　of　observation　men　had　come　to　a　standstill。　I　doubt　very　much　whether　Corvisart　in　1800　was　any　more　skilful　in　recognizing　a　case　of　pneumonia　than　was　Aretaeus　in　the　second　century　A。　D。　But　disease　had　come　to　be　more　systematically　studied；　special　clinics　were　organized；　and　teaching　became　much　more　thorough。　Anyone　who　wishes　to　have　a　picture　of　the　medical　schools　in　Europe　in　the　first　few　years　of　the　century；　should　read　the　account　of　the　travels　of　Joseph　Frank　of　Vienna。＇10＇　The　description　of　Corvisart　is　of　a　pioneer　in　clinical　teaching　whose　method　remains　in　vogue　today　in　Francethe　ward　visit；　followed　by　a　systemat