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С˵£º a history of science-4 ×ÖÊý£º ÿҳ4000×Ö

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Simply¡¡stated£»¡¡every¡¡organ¡¡or¡¡muscle¡¡of¡¡the¡¡body¡¡is¡¡supplied¡¡by¡¡one¡¡large¡¡artery£»¡¡whose¡¡main¡¡trunk¡¡distributes¡¡the¡¡blood¡¡into¡¡its¡¡lesser¡¡branches£»¡¡and¡¡thence¡¡through¡¡the¡¡capillaries¡£¡¡Cutting¡¡off¡¡this¡¡main¡¡artery£»¡¡it¡¡would¡¡seem£»¡¡should¡¡cut¡¡off¡¡entirely¡¡the¡¡blood¡­supply¡¡to¡¡the¡¡particular¡¡organ¡¡which¡¡is¡¡supplied¡¡by¡¡this¡¡vessel£»¡¡and¡¡until¡¡the¡¡time¡¡of¡¡Hunter's¡¡demonstration¡¡this¡¡belief¡¡was¡¡held¡¡by¡¡most¡¡physiologists¡£¡¡But¡¡nature¡¡has¡¡made¡¡a¡¡provision¡¡for¡¡this¡¡possible¡¡stoppage¡¡of¡¡blood¡­supply¡¡from¡¡a¡¡single¡¡source£»¡¡and¡¡has¡¡so¡¡arranged¡¡that¡¡some¡¡of¡¡the¡¡small¡¡arterial¡¡branches¡¡coming¡¡from¡¡the¡¡main¡¡supply¡­trunk¡¡are¡¡connected¡¡with¡¡other¡¡arterial¡¡branches¡¡coming¡¡from¡¡some¡¡other¡¡supply¡­trunk¡£¡¡Under¡¡normal¡¡conditions¡¡the¡¡main¡¡arterial¡¡trunks¡¡supply¡¡their¡¡respective¡¡organs£»¡¡the¡¡little¡¡connecting¡¡arterioles¡¡playing¡¡an¡¡insignificant¡¡part¡£¡¡But¡¡let¡¡the¡¡main¡¡supply¡­trunk¡¡be¡¡cut¡¡off¡¡or¡¡stopped¡¡for¡¡whatever¡¡reason£»¡¡and¡¡a¡¡remarkable¡¡thing¡¡takes¡¡place¡£¡¡The¡¡little¡¡connecting¡¡branches¡¡begin¡¡at¡¡once¡¡to¡¡enlarge¡¡and¡¡draw¡¡blood¡¡from¡¡the¡¡neighboring¡¡uninjured¡¡supply¡­trunk£»¡¡This¡¡enlargement¡¡continues¡¡until¡¡at¡¡last¡¡a¡¡new¡¡route¡¡for¡¡the¡¡circulation¡¡has¡¡been¡¡established£»¡¡the¡¡organ¡¡no¡¡longer¡¡depending¡¡on¡¡the¡¡now¡¡defunct¡¡original¡¡arterial¡¡trunk£»¡¡but¡¡getting¡¡on¡¡as¡¡well¡¡as¡¡before¡¡by¡¡this¡¡¡¨collateral¡¨¡¡circulation¡¡that¡¡has¡¡been¡¡established¡£

The¡¡thorough¡¡understanding¡¡of¡¡this¡¡collateral¡¡circulation¡¡is¡¡one¡¡of¡¡the¡¡most¡¡important¡¡steps¡¡in¡¡surgery£»¡¡for¡¡until¡¡it¡¡was¡¡discovered¡¡amputations¡¡were¡¡thought¡¡necessary¡¡in¡¡such¡¡cases¡¡as¡¡those¡¡involving¡¡the¡¡artery¡¡supplying¡¡a¡¡leg¡¡or¡¡arm£»¡¡since¡¡it¡¡was¡¡supposed¡¡that£»¡¡the¡¡artery¡¡being¡¡stopped£»¡¡death¡¡of¡¡the¡¡limb¡¡and¡¡the¡¡subsequent¡¡necessity¡¡for¡¡amputation¡¡were¡¡sure¡¡to¡¡follow¡£¡¡Hunter¡¡solved¡¡this¡¡problem¡¡by¡¡a¡¡single¡¡operation¡¡upon¡¡a¡¡deer£»¡¡and¡¡his¡¡practicality¡¡as¡¡a¡¡surgeon¡¡led¡¡him¡¡soon¡¡after¡¡to¡¡apply¡¡this¡¡knowledge¡¡to¡¡a¡¡certain¡¡class¡¡of¡¡surgical¡¡cases¡¡in¡¡a¡¡most¡¡revolutionary¡¡and¡¡satisfactory¡¡manner¡£

What¡¡led¡¡to¡¡Hunter's¡¡far¡­reaching¡¡discovery¡¡was¡¡his¡¡investigation¡¡as¡¡to¡¡the¡¡cause¡¡of¡¡the¡¡growth¡¡of¡¡the¡¡antlers¡¡of¡¡the¡¡deer¡£¡¡Wishing¡¡to¡¡ascertain¡¡just¡¡what¡¡part¡¡the¡¡blood¡­supply¡¡on¡¡the¡¡opposite¡¡sides¡¡of¡¡the¡¡neck¡¡played¡¡in¡¡the¡¡process¡¡of¡¡development£»¡¡or£»¡¡perhaps¡¡more¡¡correctly£»¡¡to¡¡see¡¡what¡¡effect¡¡cutting¡¡off¡¡the¡¡main¡¡blood¡­supply¡¡would¡¡have£»¡¡Hunter¡¡had¡¡one¡¡of¡¡the¡¡deer¡¡of¡¡Richmond¡¡Park¡¡caught¡¡and¡¡tied£»¡¡while¡¡he¡¡placed¡¡a¡¡ligature¡¡around¡¡one¡¡of¡¡the¡¡carotid¡¡arteriesone¡¡of¡¡the¡¡two¡¡principal¡¡arteries¡¡that¡¡supply¡¡the¡¡head¡¡with¡¡blood¡£¡¡He¡¡observed¡¡that¡¡shortly¡¡after¡¡this¡¡the¡¡antler¡¡£¨which¡¡was¡¡only¡¡half¡¡grown¡¡and¡¡consequently¡¡very¡¡vascular£©¡¡on¡¡the¡¡side¡¡of¡¡the¡¡obliterated¡¡artery¡¡became¡¡cold¡¡to¡¡the¡¡touchfrom¡¡the¡¡lack¡¡of¡¡warmth¡­giving¡¡blood¡£¡¡There¡¡was¡¡nothing¡¡unexpected¡¡in¡¡this£»¡¡and¡¡Hunter¡¡thought¡¡nothing¡¡of¡¡it¡¡until¡¡a¡¡few¡¡days¡¡later£»¡¡when¡¡he¡¡found£»¡¡to¡¡his¡¡surprise£»¡¡that¡¡the¡¡antler¡¡had¡¡become¡¡as¡¡warm¡¡as¡¡its¡¡fellow£»¡¡and¡¡was¡¡apparently¡¡increasing¡¡in¡¡size¡£¡¡Puzzled¡¡as¡¡to¡¡how¡¡this¡¡could¡¡be£»¡¡and¡¡suspecting¡¡that¡¡in¡¡some¡¡way¡¡his¡¡ligature¡¡around¡¡the¡¡artery¡¡had¡¡not¡¡been¡¡effective£»¡¡he¡¡ordered¡¡the¡¡deer¡¡killed£»¡¡and¡¡on¡¡examination¡¡was¡¡astonished¡¡to¡¡find¡¡that¡¡while¡¡his¡¡ligature¡¡had¡¡completely¡¡shut¡¡off¡¡the¡¡blood¡­supply¡¡from¡¡the¡¡source¡¡of¡¡that¡¡carotid¡¡artery£»¡¡the¡¡smaller¡¡arteries¡¡had¡¡become¡¡enlarged¡¡so¡¡as¡¡to¡¡supply¡¡the¡¡antler¡¡with¡¡blood¡¡as¡¡well¡¡as¡¡ever£»¡¡only¡¡by¡¡a¡¡different¡¡route¡£

Hunter¡¡soon¡¡had¡¡a¡¡chance¡¡to¡¡make¡¡a¡¡practical¡¡application¡¡of¡¡the¡¡knowledge¡¡thus¡¡acquired¡£¡¡¡¡This¡¡was¡¡a¡¡case¡¡of¡¡popliteal¡¡aneurism£»¡¡operations¡¡for¡¡which¡¡had¡¡heretofore¡¡proved¡¡pretty¡¡uniformly¡¡fatal¡£¡¡An¡¡aneurism£»¡¡as¡¡is¡¡generally¡¡understood£»¡¡is¡¡an¡¡enlargement¡¡of¡¡a¡¡certain¡¡part¡¡of¡¡an¡¡artery£»¡¡this¡¡enlargement¡¡sometimes¡¡becoming¡¡of¡¡enormous¡¡size£»¡¡full¡¡of¡¡palpitating¡¡blood£»¡¡and¡¡likely¡¡to¡¡rupture¡¡with¡¡fatal¡¡results¡¡at¡¡any¡¡time¡£¡¡¡¡If¡¡by¡¡any¡¡means¡¡the¡¡blood¡¡can¡¡be¡¡allowed¡¡to¡¡remain¡¡quiet¡¡for¡¡even¡¡a¡¡few¡¡hours¡¡in¡¡this¡¡aneurism¡¡it¡¡will¡¡form¡¡a¡¡clot£»¡¡contract£»¡¡and¡¡finally¡¡be¡¡absorbed¡¡and¡¡disappear¡¡without¡¡any¡¡evil¡¡results¡£¡¡The¡¡problem¡¡of¡¡keeping¡¡the¡¡blood¡¡quiet£»¡¡with¡¡the¡¡heart¡¡continually¡¡driving¡¡it¡¡through¡¡the¡¡vessel£»¡¡is¡¡not¡¡a¡¡simple¡¡one£»¡¡and¡¡in¡¡Hunter's¡¡time¡¡was¡¡considered¡¡so¡¡insurmountable¡¡that¡¡some¡¡surgeons¡¡advocated¡¡amputation¡¡of¡¡any¡¡member¡¡having¡¡an¡¡aneurism£»¡¡while¡¡others¡¡cut¡¡down¡¡upon¡¡the¡¡tumor¡¡itself¡¡and¡¡attempted¡¡to¡¡tie¡¡off¡¡the¡¡artery¡¡above¡¡and¡¡below¡£¡¡The¡¡first¡¡of¡¡these¡¡operations¡¡maimed¡¡the¡¡patient¡¡for¡¡life£»¡¡while¡¡the¡¡second¡¡was¡¡likely¡¡to¡¡prove¡¡fatal¡£

In¡¡pondering¡¡over¡¡what¡¡he¡¡had¡¡learned¡¡about¡¡collateral¡¡circulation¡¡and¡¡the¡¡time¡¡required¡¡for¡¡it¡¡to¡¡become¡¡fully¡¡established£»¡¡Hunter¡¡conceived¡¡the¡¡idea¡¡that¡¡if¡¡the¡¡blood¡­supply¡¡was¡¡cut¡¡off¡¡from¡¡above¡¡the¡¡aneurism£»¡¡thus¡¡temporarily¡¡preventing¡¡the¡¡ceaseless¡¡pulsations¡¡from¡¡the¡¡heart£»¡¡this¡¡blood¡¡would¡¡coagulate¡¡and¡¡form¡¡a¡¡clot¡¡before¡¡the¡¡collateral¡¡circulation¡¡could¡¡become¡¡established¡¡or¡¡could¡¡affect¡¡it¡£¡¡¡¡The¡¡patient¡¡upon¡¡whom¡¡he¡¡performed¡¡his¡¡now¡¡celebrated¡¡operation¡¡was¡¡afflicted¡¡with¡¡a¡¡popliteal¡¡aneurismthat¡¡is£»¡¡the¡¡aneurism¡¡was¡¡located¡¡on¡¡the¡¡large¡¡popliteal¡¡artery¡¡just¡¡behind¡¡the¡¡knee¡­joint¡£¡¡Hunter£»¡¡therefore£»¡¡tied¡¡off¡¡the¡¡femoral£»¡¡or¡¡main¡¡supplying¡¡artery¡¡in¡¡the¡¡thigh£»¡¡a¡¡little¡¡distance¡¡above¡¡the¡¡aneurism¡£¡¡The¡¡operation¡¡was¡¡entirely¡¡successful£»¡¡and¡¡in¡¡six¡¡weeks'¡¡time¡¡the¡¡patient¡¡was¡¡able¡¡to¡¡leave¡¡the¡¡hospital£»¡¡and¡¡with¡¡two¡¡sound¡¡limbs¡£¡¡Naturally¡¡the¡¡simplicity¡¡and¡¡success¡¡of¡¡this¡¡operation¡¡aroused¡¡the¡¡attention¡¡of¡¡Europe£»¡¡and£»¡¡alone£»¡¡would¡¡have¡¡made¡¡the¡¡name¡¡of¡¡Hunter¡¡immortal¡¡in¡¡the¡¡annals¡¡of¡¡surgery¡£¡¡¡¡The¡¡operation¡¡has¡¡ever¡¡since¡¡been¡¡called¡¡the¡¡¡¨Hunterian¡¨¡¡operation¡¡for¡¡aneurism£»¡¡but¡¡there¡¡is¡¡reason¡¡to¡¡believe¡¡that¡¡Dominique¡¡Anel¡¡£¨born¡¡about¡¡1679£©¡¡performed¡¡a¡¡somewhat¡¡similar¡¡operation¡¡several¡¡years¡¡earlier¡£¡¡It¡¡is¡¡probable£»¡¡however£»¡¡that¡¡Hunter¡¡had¡¡never¡¡heard¡¡of¡¡this¡¡work¡¡of¡¡Anel£»¡¡and¡¡that¡¡his¡¡operation¡¡was¡¡the¡¡outcome¡¡of¡¡his¡¡own¡¡independent¡¡reasoning¡¡from¡¡the¡¡facts¡¡he¡¡had¡¡learned¡¡about¡¡collateral¡¡circulation¡£¡¡Furthermore£»¡¡Hunter's¡¡mode¡¡of¡¡operation¡¡was¡¡a¡¡much¡¡better¡¡one¡¡than¡¡Anel's£»¡¡and£»¡¡while¡¡Anel's¡¡must¡¡claim¡¡priority£»¡¡the¡¡credit¡¡of¡¡making¡¡it¡¡widely¡¡known¡¡will¡¡always¡¡be¡¡Hunter's¡£

The¡¡great¡¡services¡¡of¡¡Hunter¡¡were¡¡recognized¡¡both¡¡at¡¡home¡¡and¡¡abroad£»¡¡and¡¡honors¡¡and¡¡positions¡¡of¡¡honor¡¡and¡¡responsibility¡¡were¡¡given¡¡him¡£¡¡In¡¡1776¡¡he¡¡was¡¡appointed¡¡surgeon¡­extraordinary¡¡to¡¡the¡¡king£»¡¡in¡¡1783¡¡he¡¡was¡¡elected¡¡a¡¡member¡¡of¡¡the¡¡Royal¡¡Society¡¡of¡¡Medicine¡¡and¡¡of¡¡the¡¡Royal¡¡Academy¡¡of¡¡Surgery¡¡at¡¡Paris£»¡¡in¡¡1786¡¡he¡¡became¡¡deputy¡¡surgeon¡­general¡¡of¡¡the¡¡army£»¡¡and¡¡in¡¡1790¡¡he¡¡was¡¡appointed¡¡surgeon¡­general¡¡and¡¡inspector¡­general¡¡of¡¡hospitals¡£¡¡All¡¡these¡¡positions¡¡he¡¡filled¡¡with¡¡credit£»¡¡and¡¡he¡¡was¡¡actively¡¡engaged¡¡in¡¡his¡¡tireless¡¡pursuit¡¡of¡¡knowledge¡¡and¡¡in¡¡discharging¡¡his¡¡many¡¡duties¡¡when¡¡in¡¡October£»¡¡1793£»¡¡he¡¡was¡¡stricken¡¡while¡¡addressing¡¡some¡¡colleagues£»¡¡and¡¡fell¡¡dead¡¡in¡¡the¡¡arms¡¡of¡¡a¡¡fellow¡­physician¡£


LAZZARO¡¡SPALLANZANI

Hunter's¡¡great¡¡rival¡¡among¡¡contemporary¡¡physiologists¡¡was¡¡the¡¡Italian¡¡Lazzaro¡¡Spallanzani¡¡£¨1729¡­1799£©£»¡¡one¡¡of¡¡the¡¡most¡¡picturesque¡¡figures¡¡in¡¡the¡¡history¡¡of¡¡science¡£¡¡He¡¡was¡¡not¡¡educated¡¡either¡¡as¡¡a¡¡scientist¡¡or¡¡physician£»¡¡devoting£»¡¡himself¡¡at¡¡first¡¡to¡¡philosophy¡¡and¡¡the¡¡languages£»¡¡afterwards¡¡studying¡¡law£»¡¡and¡¡later¡¡taking¡¡orders¡£¡¡But¡¡he¡¡was¡¡a¡¡keen¡¡observer¡¡of¡¡nature¡¡and¡¡of¡¡a¡¡questioning¡¡and¡¡investigating¡¡mind£»¡¡so¡¡that¡¡he¡¡is¡¡remembered¡¡now¡¡chiefly¡¡for¡¡his¡¡discoveries¡¡and¡¡investigations¡¡in¡¡the¡¡biological¡¡sciences¡£¡¡One¡¡important¡¡demonstration¡¡was¡¡his¡¡controversion¡¡of¡¡the¡¡theory¡¡of¡¡abiogenesis£»¡¡or¡¡¡¨spontaneous¡¡generation£»¡¨¡¡as¡¡propounded¡¡by¡¡Needham¡¡and¡¡Buffon¡£¡¡¡¡At¡¡the¡¡time¡¡of¡¡Needham's¡¡experiments¡¡it¡¡had¡¡long¡¡been¡¡observed¡¡that¡¡when¡¡animal¡¡or¡¡vegetable¡¡matter¡¡had¡¡lain¡¡in¡¡water¡¡for¡¡a¡¡little¡¡timelong¡¡enough¡¡for¡¡it¡¡to¡¡begin¡¡to¡¡undergo¡¡decompositionthe¡¡water¡¡became¡¡filled¡¡with¡¡microscopic¡¡creatures£»¡¡the¡¡¡¨infusoria¡¡animalculis¡£¡¨¡¡This¡¡would¡¡tend¡¡to¡¡show£»¡¡either¡¡that¡¡the¡¡water¡¡or¡¡the¡¡animal¡¡or¡¡vegetable¡¡substance¡¡contained¡¡the¡¡¡¨germs¡¨¡¡of¡¡these¡¡minute¡¡organisms£»¡¡or¡¡else¡¡that¡¡they¡¡were¡¡generated¡¡spontaneously¡£¡¡It¡¡was¡¡known¡¡that¡¡boiling¡¡killed¡¡these¡¡animalcules£»¡¡and¡¡Needham¡¡agreed£»¡¡therefore£»¡¡that¡¡if¡¡he¡¡first¡¡heated¡¡the¡¡meat¡¡or¡¡vegetables£»¡¡and¡¡also¡¡the¡¡water¡¡containing¡¡them£»¡¡and¡¡then¡¡placed¡¡them¡¡in¡¡hermetically¡¡scaled¡¡jarsif¡¡he¡¡did¡¡this£»¡¡and¡¡still¡¡the¡¡animalcules¡¡made¡¡their¡¡appearance£»¡¡it¡¡would¡¡be¡¡proof¡­positive¡¡that¡¡they¡¡had¡¡been¡¡generated¡¡spontaneously¡£¡¡¡¡Accordingly¡¡be¡¡made¡¡numerous¡¡experiments£»¡¡always¡¡with¡¡the¡¡same¡¡resultsthat¡¡after¡¡a¡¡few¡¡days¡¡the¡¡water¡¡was¡¡found¡¡to¡¡swarm¡¡with¡¡the¡¡microscopic¡¡creatures¡£¡¡The¡¡thing¡¡seemed¡¡proven¡¡beyond¡¡questionproviding£»¡¡of¡¡course£»¡¡that¡¡there¡¡had¡¡been¡¡no¡¡slips¡¡in¡¡the¡¡experiments¡£

But¡¡Abbe¡¡Spallanzani¡¡thought¡¡that¡¡he¡¡detected¡¡such¡¡slips¡¡in¡¡Needham's¡¡experiment¡£¡¡¡¡The¡¡possibility¡¡of¡¡such¡¡slips¡¡might¡¡come¡¡in¡¡several¡¡ways£º¡¡¡¡the¡¡contents¡¡of¡¡the¡¡jar¡¡might¡¡not¡¡have¡¡been¡¡boiled¡¡for¡¡a¡¡sufficient¡¡length¡¡of¡¡time¡¡to¡¡kill¡¡all¡¡the¡¡germs£»¡¡or¡¡the¡¡air¡¡might¡¡not¡¡have¡¡been¡¡excluded¡¡completely¡¡by¡¡the¡¡sealing¡¡process¡£¡¡To¡¡cover¡¡both¡¡these¡¡contingencies£»¡¡Spallanzani¡¡first¡¡hermetically¡¡sealed¡¡the¡¡glass¡¡vessels¡¡and¡¡then¡¡boiled¡¡them¡¡for¡¡three¡­quarters¡¡of¡¡an¡¡hour¡£¡¡Under¡¡these¡¡circumstances¡¡no¡¡animalcules¡¡ever¡¡made¡¡their¡¡appearancea¡¡conclusive¡¡demonstration¡¡that¡¡rendered¡¡Needham's¡¡grounds¡¡for¡¡his¡¡theory¡¡at¡¡once¡¡untenable¡££§2£§

Allied¡¡to¡¡these¡¡studies¡¡of¡¡spontaneous¡¡generation¡¡were¡¡Spallanzani's¡¡experiments¡¡and¡¡observations¡¡on¡¡the¡¡physiological¡¡processes¡¡of¡¡generation¡¡among¡¡higher¡¡animals¡£¡¡¡¡He¡¡experimented¡¡with¡¡frogs£»¡¡tortoises£»¡¡and¡¡dogs£»¡¡and¡¡settled¡¡beyon

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