The　experience　of　the　profession　must；　I　think；　run　parallel　with　that　of　the　wisest　of　its　individual　members。　　Each　time　a　plan　of　treatment　or　a　particular　remedy　comes　up　for　trial；　it　is　submitted　to　a　sharper　scrutiny。　　When　Cullen　wrote　his　Materia　Medica；　he　had　seriously　to　assail　the　practice　of　giving　burnt　toad；　which　was　still　countenanced　by　at　least　one　medical　authority　of　note。　　I　have　read　recently　in　some　medical　journal；　that　an　American　practitioner；　whose　name　is　known　to　the　country；　is　prescribing　the　hoof　of　a　horse　for　epilepsy。　　It　was　doubtless　suggested　by　that　old　fancy　of　wearing　a　portion　of　elk's　hoof　hung　round　the　neck　or　in　a　ring；　for　this　disease。　　But　it　is　hard　to　persuade　reasonable　people　to　swallow　the　abominations　of　a　former　period。　　The　evidence　which　satisfied　Fernelius　will　not　serve　one　of　our　hospital　physicians。
  In　this　way　those　articles　of　the　Materia　Medica　which　had　nothing　but　loathsomeness　to　recommend　them　have　been　gradually　dropped；　and　are　not　like　to　obtain　any　general　favor　again　with　civilized　communities。　　The　next　culprits　to　be　tried　are　the　poisons。　　I　have　never　been　in　the　least　sceptical　as　to　the　utility　of　some　of　them；　when　properly　employed。　　Though　I　believe　that　at　present；　taking　the　world　at　large；　and　leaving　out　a　few　powerful　agents　of　such　immense　value　that　they　rank　next　to　food　in　importance；　the　poisons　prescribed　for　disease　do　more　hurt　than　good；　I　have　no　doubt；　and　never　professed　to　have　any；　that　they　do　much　good　in　prudent　and　instructed　hands。　　But　I　am　very　willing　to　confess　a　great　jealousy　of　many　agents；　and　I　could　almost　wish　to　see　the　Materia　Medica　so　classed　as　to　call　suspicion　upon　certain　ones　among　them。
  Thus　the　alien　elements；　those　which　do　not　properly　enter　into　the　composition　of　any　living　tissue；　are　the　most　to　be　suspected；　mercury；　lead；　antimony；　silver；　and　the　rest；　for　the　reasons　I　have　before　mentioned。　　Even　iodine；　which；　as　it　is　found　in　certain　plants；　seems　less　remote　from　the　animal　tissues；　gives　unequivocal　proofs　from　time　to　time　that　it　is　hostile　to　some　portions　of　the　glandular　system。
  There　is；　of　course；　less　prima　facie　objection　to　those　agents　which　consist　of　assimilable　elements；　such　as　are　found　making　a　part　of　healthy　tissues。　　These　are　divisible　into　three　classes；foods；　poisons；　and　inert；　mostly　because　insoluble；　substances。　　The　food　of　one　animal　or　of　one　human　being　is　sometimes　poison　to　another；　and　vice　versa；　inert　substances　may　act　mechanically；　so　as　to　produce　the　effect　of　poisons；　but　this　division　holds　exactly　enough　for　our　purpose。
  Strictly　speaking；　every　poison　consisting　of　assimilable　elements　may　be　considered　as　unwholesome　；food。　　It　is　rejected　by　the　stomach；　or　it　produces　diarrhoea；　or　it　causes　vertigo　or　disturbance　of　the　heart's　action；　or　some　other　symptom　for　which　the　subject　of　it　would　consult　the　physician；　if　it　came　on　from　any　other　cause　than　taking　it　under　the　name　of　medicine。　　Yet　portions　of　this　unwholesome　food　which　we　call　medicine；　we　have　reason　to　believe；　are　assimilated；　thus；　castor…oil　appears　to　be　partially　digested　by　infants；　so　that　they　require　large　doses　to　affect　them　medicinally。　　Even　that　deadliest　of　poisons；　hydrocyanic　acid；　is　probably　assimilated；　and　helps　to　make　living　tissue；　if　it　do　not　kill　the　patient；　for　the　assimilable　elements　which　it　contains；　given　in　the　separate　forms　of　amygdalin　and　emulsin；　produce　no　disturbance；　unless；　as　in　Bernard's　experiments；　they　are　suffered　to　meet　in　the　digestive　organs。　　A　medicine　consisting　of　assimilable　substances　being　then　simply　unwholesome　food；　we　understand　what　is　meant　by　those　cumulative　effects　of　such　remedies　often　observed；　as　in　the　case　of　digitalis　and　strychnia。　　They　are　precisely　similar　to　the　cumulative　effects　of　a　salt　diet　in　producing　scurvy；　or　of　spurred　rye　in　producing　dry　gangrene。　　As　the　effects　of　such　substances　are　a　violence　to　the　organs；　we　should　exercise　the　same　caution　with　regard　to　their　use　that　we　would　exercise　about　any　other　kind　of　poisonous　food；partridges　at　certain　seasons；　for　instance。　　Even　where　these　poisonous　kinds　of　food　seem　to　be　useful；　we　should　still　regard　them　with　great　jealousy。　　Digitalis　lowers　the　pulse　in　febrile　conditions。　Veratrum　viride　does　the　same　thing。　　How　do　we　know　that　a　rapid　pulse　is　not　a　normal　adjustment　of　nature　to　the　condition　it　accompanies？　　Digitalis　has　gone　out　of　favor；　how　sure　are　we　that　Veratrum　viride　will　not　be　found　to　do　more　harm　than　good　in　a　case　of　internal　inflammation；　taking　the　whole　course　of　the　disease　into　consideration？　　Think　of　the　change　of　opinion　with　regard　to　the　use　of　opium　in　delirium　tremens　（which　you　remember　is　sometimes　called　delirium　vigilans）；　where　it　seemed　so　obviously　indicated；　since　the　publication　of　Dr。　Ware's　admirable　essay。　　I　respect　the　evidence　of　my　contemporaries；　but　I　cannot　forget　the　sayings　of　the　Father　of　medicine；Ars　longa；　judicium　diffcile。
  I　am　not　presuming　to　express　an　opinion　concerning　Veratrum　viride；　which　was　little　heard　of　when　I　was　still　practising　medicine。　　I　am　only　appealing　to　that　higher　court　of　experience　which　sits　in　judgment　on　all　decisions　of　the　lower　medical　tribunals；　and　which　requires　more　than　one　generation　for　its　final　verdict。
  Once　change　the　habit　of　mind　so　long　prevalent　among　practitioners　of　medicine；　once　let　it　be　everywhere　understood　that　the　presumption　is　in　favor　of　food；　and　not　of　alien　substances；　of　innocuous；　and　not　of　unwholesome　food；　for　the　sick；　that　this　presumption　requires　very　strong　evidence　in　each　particular　case　to　overcome　it；　but　that；　when　such　evidence　is　afforded；　the　alien　substance　or　the　unwholesome　food　should　be　given　boldly；　in　sufficient　quantities；　in　the　same　spirit　as　that　with　which　the　surgeon　lifts　his　knife　against　a　patient；that　is；　with　the　same　reluctance　and　the　same　determination；and　I　think　we　shall　have　and　hear　much　less　of　charlatanism　in　and　out　of　the　profession。　　The　disgrace　of　medicine　has　been　that　colossal　system　of　self…deception；　in　obedience　to　which　mines　have　been　emptied　of　their　cankering　minerals；　the　vegetable　kingdom　robbed　of　all　its　noxious　growths；　the　entrails　of　animals　taxed　for　their　impurities；　the　poison…bags　of　reptiles　drained　of　their　venom；　and　all　the　inconceivable　abominations　thus　obtained　thrust　down　the　throats　of　human　beings　suffering　from　some　fault　of　organization；　nourishment；　or　vital　stimulation。
  Much　as　we　have　gained；　we　have　not　yet　thoroughly　shaken　off　the　notion　that　poison　is　the　natural　food　of　disease；　as　wholesome　aliment　is　the　support　of　health。　　Cowper's　lines；　in　〃The　Task；〃　show　the　matter…of…course　practice　of　his　time：
  〃He　does　not　scorn　it；　who　has　long　endured　　　　　　A　fever's　agonies；　and　fed　on　drugs。〃
  Dr。　Kimball　of　Lowell；　who　has　been　in　the　habit　of　seeing　a　great　deal　more　of　typhoid　fever　than　most　practitioners；　and　whose　surgical　exploits　show　him　not　to　be　wanting　in　boldness　or　enterprise；　can　tell　you　whether　he　finds　it　necessary　to　feed　his　patients　on　drugs　or　not。　　His　experience　is；　I　believe；　that　of　the　most　enlightened　and　advanced　portion　of　the　profession；　yet　I　think　that　even　in　typhoid　fever；　and　certainly　in　many　other　complaints；　the　effects　of　ancient　habits　and　prejudices　may　still　be　seen　in　the　practice　of　some　educated　physicians。
  To　you；　young　men；　it　belongs　to　judge　all　that　has　gone　before　you。　You　come　nearer　to　the　great　fathers　of　modern　medicine　than　some　of　you　imagine。　　Three　of　my　own　instructors　attended　Dr。　Rush's　Lectures。　　The　illustrious　Haller　mentions　Rush's　inaugural　thesis　in　his　〃Bibliotheca　Anatomica；〃　and　this　same　Haller；　brought　so　close　to　us；　tells　us　he　remembers　Ruysch；　then　an　old　man；　and　used　to　carry　letters　between　him　and　Boerhaave。　　Look　through　the　history　of　medicine　from　Boerhaave　to　this　present　day。　　You　will　see　at　once　that　medical　doctrine　and　practice　have　undergone　a　long　series　of　changes。　　You　will　see　that　the　doctrine　and　practice　of　our　own　time　must　probably　change　in　their　turn；　and　that；　if　we　can　trust　at　all　to　the　indications　of　their　course；　it　will　be　in　the　direction　of　an　improved　hygiene　and　a　simplified　treatment。　　Especially　will　the　old　habit　of　violating　the　instincts　of　the　sick　give　place　to　a　judicious　study　of　these　same　instincts。　　It　will　be　found　that　bodily；　like　mental　insanity；　is　best　managed；　for　the　most　part；　by　natural　soothing　agencies。　　Two　centuries　ago　there　was　a　prescription　for　scurvy　containing　〃stercoris　taurini　et　anserini　par；　quantitas　trium　magnarum　nucum；〃　of　the　hell…broth　containing　which　〃guoties…cumque　sitit　oeger；　large　bibit。〃　　　When　I　have　recalled　the　humane　common…sense　of　Captain　Cook　in　the　matter　of　preventing　this　disease；　when　I　have　heard　my　friend；　Mr。　Dana；　describing　the　avidity　with　which　the　scurvy…stricken　sailors　snuffed　up　the　earthy　fragrance　of　fresh　raw　potatoes；　the　food　which　was　to　supply　the　elements　wanting　to　their　spongy　tissues；　I　have　recognized　that　the　perfection　of　art　is　often　a　return　to　nature；　and　seen　in　this　single　instance　the　ge