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

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hat¡¡putrefaction£»¡¡in¡¡short£»¡¡has¡¡its¡¡foundation¡¡in¡¡the¡¡activities¡¡of¡¡these¡¡so¡­called¡¡anaerobic¡¡bacteria¡£

In¡¡a¡¡word£»¡¡Pasteur¡¡showed¡¡that¡¡all¡¡the¡¡many¡¡familiar¡¡processes¡¡of¡¡the¡¡decay¡¡of¡¡organic¡¡tissues¡¡are£»¡¡in¡¡effect£»¡¡forms¡¡of¡¡fermentation£»¡¡and¡¡would¡¡not¡¡take¡¡place¡¡at¡¡all¡¡except¡¡for¡¡the¡¡presence¡¡of¡¡the¡¡living¡¡micro¡­organisms¡£¡¡A¡¡piece¡¡of¡¡meat£»¡¡for¡¡example£»¡¡suspended¡¡in¡¡an¡¡atmosphere¡¡free¡¡from¡¡germs£»¡¡will¡¡dry¡¡up¡¡gradually£»¡¡without¡¡the¡¡slightest¡¡sign¡¡of¡¡putrefaction£»¡¡regardless¡¡of¡¡the¡¡temperature¡¡or¡¡other¡¡conditions¡¡to¡¡which¡¡it¡¡may¡¡have¡¡been¡¡subjected¡£¡¡Let¡¡us¡¡witness¡¡one¡¡or¡¡two¡¡series¡¡of¡¡these¡¡experiments¡¡as¡¡presented¡¡by¡¡Pasteur¡¡himself¡¡in¡¡one¡¡of¡¡his¡¡numerous¡¡papers¡¡before¡¡the¡¡Academy¡¡of¡¡Sciences¡£


EXPERIMENTS¡¡WITH¡¡GRAPE¡¡SUGAR

¡¨In¡¡the¡¡course¡¡of¡¡the¡¡discussion¡¡which¡¡took¡¡place¡¡before¡¡the¡¡Academy¡¡upon¡¡the¡¡subject¡¡of¡¡the¡¡generation¡¡of¡¡ferments¡¡properly¡¡so¡­called£»¡¡there¡¡was¡¡a¡¡good¡¡deal¡¡said¡¡about¡¡that¡¡of¡¡wine£»¡¡the¡¡oldest¡¡fermentation¡¡known¡£¡¡On¡¡this¡¡account¡¡I¡¡decided¡¡to¡¡disprove¡¡the¡¡theory¡¡of¡¡M¡£¡¡Fremy¡¡by¡¡a¡¡decisive¡¡experiment¡¡bearing¡¡solely¡¡upon¡¡the¡¡juice¡¡of¡¡grapes¡£

¡¨I¡¡prepared¡¡forty¡¡flasks¡¡of¡¡a¡¡capacity¡¡of¡¡from¡¡two¡¡hundred¡¡and¡¡fifty¡¡to¡¡three¡¡hundred¡¡cubic¡¡centimetres¡¡and¡¡filled¡¡them¡¡half¡¡full¡¡with¡¡filtered¡¡grape¡­must£»¡¡perfectly¡¡clear£»¡¡and¡¡which£»¡¡as¡¡is¡¡the¡¡case¡¡of¡¡all¡¡acidulated¡¡liquids¡¡that¡¡have¡¡been¡¡boiled¡¡for¡¡a¡¡few¡¡seconds£»¡¡remains¡¡uncontaminated¡¡although¡¡the¡¡curved¡¡neck¡¡of¡¡the¡¡flask¡¡containing¡¡them¡¡remain¡¡constantly¡¡open¡¡during¡¡several¡¡months¡¡or¡¡years¡£

¡¨In¡¡a¡¡small¡¡quantity¡¡of¡¡water¡¡I¡¡washed¡¡a¡¡part¡¡of¡¡a¡¡bunch¡¡of¡¡grapes£»¡¡the¡¡grapes¡¡and¡¡the¡¡stalks¡¡together£»¡¡and¡¡the¡¡stalks¡¡separately¡£¡¡This¡¡washing¡¡was¡¡easily¡¡done¡¡by¡¡means¡¡of¡¡a¡¡small¡¡badger's¡­hair¡¡brush¡£¡¡The¡¡washing¡­water¡¡collected¡¡the¡¡dust¡¡upon¡¡the¡¡surface¡¡of¡¡the¡¡grapes¡¡and¡¡the¡¡stalks£»¡¡and¡¡it¡¡was¡¡easily¡¡shown¡¡under¡¡the¡¡microscope¡¡that¡¡this¡¡water¡¡held¡¡in¡¡suspension¡¡a¡¡multitude¡¡of¡¡minute¡¡organisms¡¡closely¡¡resembling¡¡either¡¡fungoid¡¡spores£»¡¡or¡¡those¡¡of¡¡alcoholic¡¡Yeast£»¡¡or¡¡those¡¡of¡¡Mycoderma¡¡vini£»¡¡etc¡£¡¡This¡¡being¡¡done£»¡¡ten¡¡of¡¡the¡¡forty¡¡flasks¡¡were¡¡preserved¡¡for¡¡reference£»¡¡in¡¡ten¡¡of¡¡the¡¡remainder£»¡¡through¡¡the¡¡straight¡¡tube¡¡attached¡¡to¡¡each£»¡¡some¡¡drops¡¡of¡¡the¡¡washing¡­water¡¡were¡¡introduced£»¡¡in¡¡a¡¡third¡¡series¡¡of¡¡ten¡¡flasks¡¡a¡¡few¡¡drops¡¡of¡¡the¡¡same¡¡liquid¡¡were¡¡placed¡¡after¡¡it¡¡had¡¡been¡¡boiled£»¡¡and£»¡¡finally£»¡¡in¡¡the¡¡ten¡¡remaining¡¡flasks¡¡were¡¡placed¡¡some¡¡drops¡¡of¡¡grape¡­juice¡¡taken¡¡from¡¡the¡¡inside¡¡of¡¡a¡¡perfect¡¡fruit¡£¡¡¡¡In¡¡order¡¡to¡¡carry¡¡out¡¡this¡¡experiment£»¡¡the¡¡straight¡¡tube¡¡of¡¡each¡¡flask¡¡was¡¡drawn¡¡out¡¡into¡¡a¡¡fine¡¡and¡¡firm¡¡point¡¡in¡¡the¡¡lamp£»¡¡and¡¡then¡¡curved¡£¡¡This¡¡fine¡¡and¡¡closed¡¡point¡¡was¡¡filed¡¡round¡¡near¡¡the¡¡end¡¡and¡¡inserted¡¡into¡¡the¡¡grape¡¡while¡¡resting¡¡upon¡¡some¡¡hard¡¡substance¡£¡¡When¡¡the¡¡point¡¡was¡¡felt¡¡to¡¡touch¡¡the¡¡support¡¡of¡¡the¡¡grape¡¡it¡¡was¡¡by¡¡a¡¡slight¡¡pressure¡¡broken¡¡off¡¡at¡¡the¡¡point¡¡file¡¡mark¡£¡¡Then£»¡¡if¡¡care¡¡had¡¡been¡¡taken¡¡to¡¡create¡¡a¡¡slight¡¡vacuum¡¡in¡¡the¡¡flask£»¡¡a¡¡drop¡¡of¡¡the¡¡juice¡¡of¡¡the¡¡grape¡¡got¡¡into¡¡it£»¡¡the¡¡filed¡¡point¡¡was¡¡withdrawn£»¡¡and¡¡the¡¡aperture¡¡immediately¡¡closed¡¡in¡¡the¡¡alcohol¡¡lamp¡£¡¡¡¡This¡¡decreased¡¡pressure¡¡of¡¡the¡¡atmosphere¡¡in¡¡the¡¡flask¡¡was¡¡obtained¡¡by¡¡the¡¡following¡¡means£º¡¡After¡¡warming¡¡the¡¡sides¡¡of¡¡the¡¡flask¡¡either¡¡in¡¡the¡¡hands¡¡or¡¡in¡¡the¡¡lamp¡­flame£»¡¡thus¡¡causing¡¡a¡¡small¡¡quantity¡¡of¡¡air¡¡to¡¡be¡¡driven¡¡out¡¡of¡¡the¡¡end¡¡of¡¡the¡¡curved¡¡neck£»¡¡this¡¡end¡¡was¡¡closed¡¡in¡¡the¡¡lamp¡£¡¡After¡¡the¡¡flask¡¡was¡¡cooled£»¡¡there¡¡was¡¡a¡¡tendency¡¡to¡¡suck¡¡in¡¡the¡¡drop¡¡of¡¡grape¡­juice¡¡in¡¡the¡¡manner¡¡just¡¡described¡£

¡¨The¡¡drop¡¡of¡¡grape¡­juice¡¡which¡¡enters¡¡into¡¡the¡¡flask¡¡by¡¡this¡¡suction¡¡ordinarily¡¡remains¡¡in¡¡the¡¡curved¡¡part¡¡of¡¡the¡¡tube£»¡¡so¡¡that¡¡to¡¡mix¡¡it¡¡with¡¡the¡¡must¡¡it¡¡was¡¡necessary¡¡to¡¡incline¡¡the¡¡flask¡¡so¡¡as¡¡to¡¡bring¡¡the¡¡must¡¡into¡¡contact¡¡with¡¡the¡¡juice¡¡and¡¡then¡¡replace¡¡the¡¡flask¡¡in¡¡its¡¡normal¡¡position¡£¡¡The¡¡four¡¡series¡¡of¡¡comparative¡¡experiments¡¡produced¡¡the¡¡following¡¡results£º

¡¨The¡¡first¡¡ten¡¡flasks¡¡containing¡¡the¡¡grape¡­must¡¡boiled¡¡in¡¡pure¡¡air¡¡did¡¡not¡¡show¡¡the¡¡production¡¡of¡¡any¡¡organism¡£¡¡The¡¡grape¡­must¡¡could¡¡possibly¡¡remain¡¡in¡¡them¡¡for¡¡an¡¡indefinite¡¡number¡¡of¡¡years¡£¡¡¡¡Those¡¡in¡¡the¡¡second¡¡series£»¡¡containing¡¡the¡¡water¡¡in¡¡which¡¡the¡¡grapes¡¡had¡¡been¡¡washed¡¡separately¡¡and¡¡together£»¡¡showed¡¡without¡¡exception¡¡an¡¡alcoholic¡¡fermentation¡¡which¡¡in¡¡several¡¡cases¡¡began¡¡to¡¡appear¡¡at¡¡the¡¡end¡¡of¡¡forty¡­eight¡¡hours¡¡when¡¡the¡¡experiment¡¡took¡¡place¡¡at¡¡ordinary¡¡summer¡¡temperature¡£¡¡At¡¡the¡¡same¡¡time¡¡that¡¡the¡¡yeast¡¡appeared£»¡¡in¡¡the¡¡form¡¡of¡¡white¡¡traces£»¡¡which¡¡little¡¡by¡¡little¡¡united¡¡themselves¡¡in¡¡the¡¡form¡¡of¡¡a¡¡deposit¡¡on¡¡the¡¡sides¡¡of¡¡all¡¡the¡¡flasks£»¡¡there¡¡were¡¡seen¡¡to¡¡form¡¡little¡¡flakes¡¡of¡¡Mycellium£»¡¡often¡¡as¡¡a¡¡single¡¡fungoid¡¡growth¡¡or¡¡in¡¡combination£»¡¡these¡¡fungoid¡¡growths¡¡being¡¡quite¡¡independent¡¡of¡¡the¡¡must¡¡or¡¡of¡¡any¡¡alcoholic¡¡yeast¡£¡¡¡¡Often£»¡¡also£»¡¡the¡¡Mycoderma¡¡vini¡¡appeared¡¡after¡¡some¡¡days¡¡upon¡¡the¡¡surface¡¡of¡¡the¡¡liquid¡£¡¡The¡¡Vibria¡¡and¡¡the¡¡lactic¡¡ferments¡¡properly¡¡so¡¡called¡¡did¡¡not¡¡appear¡¡on¡¡account¡¡of¡¡the¡¡nature¡¡of¡¡the¡¡liquid¡£

¡¨The¡¡third¡¡series¡¡of¡¡flasks£»¡¡the¡¡washing¡­water¡¡in¡¡which¡¡had¡¡been¡¡previously¡¡boiled£»¡¡remained¡¡unchanged£»¡¡as¡¡in¡¡the¡¡first¡¡series¡£¡¡Those¡¡of¡¡the¡¡fourth¡¡series£»¡¡in¡¡which¡¡was¡¡the¡¡juice¡¡of¡¡the¡¡interior¡¡of¡¡the¡¡grapes£»¡¡remained¡¡equally¡¡free¡¡from¡¡change£»¡¡although¡¡I¡¡was¡¡not¡¡always¡¡able£»¡¡on¡¡account¡¡of¡¡the¡¡delicacy¡¡of¡¡the¡¡experiment£»¡¡to¡¡eliminate¡¡every¡¡chance¡¡of¡¡error¡£¡¡These¡¡experiments¡¡cannot¡¡leave¡¡the¡¡least¡¡doubt¡¡in¡¡the¡¡mind¡¡as¡¡to¡¡the¡¡following¡¡facts£º

Grape¡­must£»¡¡after¡¡heating£»¡¡never¡¡ferments¡¡on¡¡contact¡¡with¡¡the¡¡air£»¡¡when¡¡the¡¡air¡¡has¡¡been¡¡deprived¡¡of¡¡the¡¡germs¡¡which¡¡it¡¡ordinarily¡¡holds¡¡in¡¡a¡¡state¡¡of¡¡suspension¡£

¡¨The¡¡boiled¡¡grape¡­must¡¡ferments¡¡when¡¡there¡¡is¡¡introduced¡¡into¡¡it¡¡a¡¡very¡¡small¡¡quantity¡¡of¡¡water¡¡in¡¡which¡¡the¡¡surface¡¡of¡¡the¡¡grapes¡¡or¡¡their¡¡stalks¡¡have¡¡been¡¡washed¡£

¡¨The¡¡grape¡­must¡¡does¡¡not¡¡ferment¡¡when¡¡this¡¡washing¡­water¡¡has¡¡been¡¡boiled¡¡and¡¡afterwards¡¡cooled¡£

¡¨The¡¡grape¡­must¡¡does¡¡not¡¡ferment¡¡when¡¡there¡¡is¡¡added¡¡to¡¡it¡¡a¡¡small¡¡quantity¡¡of¡¡the¡¡juice¡¡of¡¡the¡¡inside¡¡of¡¡the¡¡grape¡£

¡¨The¡¡yeast£»¡¡therefore£»¡¡which¡¡causes¡¡the¡¡fermentation¡¡of¡¡the¡¡grapes¡¡in¡¡the¡¡vintage¡­tub¡¡comes¡¡from¡¡the¡¡outside¡¡and¡¡not¡¡from¡¡the¡¡inside¡¡of¡¡the¡¡grapes¡£¡¡¡¡Thus¡¡is¡¡destroyed¡¡the¡¡hypothesis¡¡of¡¡MM¡£¡¡¡¡Trecol¡¡and¡¡Fremy£»¡¡who¡¡surmised¡¡that¡¡the¡¡albuminous¡¡matter¡¡transformed¡¡itself¡¡into¡¡yeast¡¡on¡¡account¡¡of¡¡the¡¡vital¡¡germs¡¡which¡¡were¡¡natural¡¡to¡¡it¡£¡¡With¡¡greater¡¡reason£»¡¡therefore£»¡¡there¡¡is¡¡no¡¡longer¡¡any¡¡question¡¡of¡¡the¡¡theory¡¡of¡¡Liebig¡¡of¡¡the¡¡transformation¡¡of¡¡albuminoid¡¡matter¡¡into¡¡ferments¡¡on¡¡account¡¡of¡¡the¡¡oxidation¡£¡¨


FOREIGN¡¡ORGANISMS¡¡AND¡¡THE¡¡WORT¡¡OF¡¡BEER

¡¨The¡¡method¡¡which¡¡I¡¡have¡¡just¡¡followed£»¡¨¡¡Pasteur¡¡continues£»¡¡¡¨in¡¡order¡¡to¡¡show¡¡that¡¡there¡¡exists¡¡a¡¡correlation¡¡between¡¡the¡¡diseases¡¡of¡¡beer¡¡and¡¡certain¡¡microscopic¡¡organisms¡¡leaves¡¡no¡¡room¡¡for¡¡doubt£»¡¡it¡¡seems¡¡to¡¡me£»¡¡in¡¡regard¡¡to¡¡the¡¡principles¡¡I¡¡am¡¡expounding¡£

¡¨Every¡¡time¡¡that¡¡the¡¡microscope¡¡reveals¡¡in¡¡the¡¡leaven£»¡¡and¡¡especially¡¡in¡¡the¡¡active¡¡yeast£»¡¡the¡¡production¡¡of¡¡organisms¡¡foreign¡¡to¡¡the¡¡alcoholic¡¡yeast¡¡properly¡¡so¡¡called£»¡¡the¡¡flavor¡¡of¡¡the¡¡beer¡¡leaves¡¡something¡¡to¡¡be¡¡desired£»¡¡much¡¡or¡¡little£»¡¡according¡¡to¡¡the¡¡abundance¡¡and¡¡the¡¡character¡¡of¡¡these¡¡little¡¡germs¡£¡¡Moreover£»¡¡when¡¡a¡¡finished¡¡beer¡¡of¡¡good¡¡quality¡¡loses¡¡after¡¡a¡¡time¡¡its¡¡agreeable¡¡flavor¡¡and¡¡becomes¡¡sour£»¡¡it¡¡can¡¡be¡¡easily¡¡shown¡¡that¡¡the¡¡alcoholic¡¡yeast¡¡deposited¡¡in¡¡the¡¡bottles¡¡or¡¡the¡¡casks£»¡¡although¡¡originally¡¡pure£»¡¡at¡¡least¡¡in¡¡appearance£»¡¡is¡¡found¡¡to¡¡be¡¡contaminated¡¡gradually¡¡with¡¡these¡¡filiform¡¡or¡¡other¡¡ferments¡£¡¡All¡¡this¡¡can¡¡be¡¡deduced¡¡from¡¡the¡¡facts¡¡already¡¡given£»¡¡but¡¡some¡¡critics¡¡may¡¡perhaps¡¡declare¡¡that¡¡these¡¡foreign¡¡ferments¡¡are¡¡the¡¡consequences¡¡of¡¡the¡¡diseased¡¡condition£»¡¡itself¡¡produced¡¡by¡¡unknown¡¡causes¡£

¡¨Although¡¡this¡¡gratuitous¡¡hypothesis¡¡may¡¡be¡¡difficult¡¡to¡¡uphold£»¡¡I¡¡will¡¡endeavor¡¡to¡¡corroborate¡¡the¡¡preceding¡¡observations¡¡by¡¡a¡¡clearer¡¡method¡¡of¡¡investigation¡£¡¡¡¡This¡¡consists¡¡in¡¡showing¡¡that¡¡the¡¡beer¡¡never¡¡has¡¡any¡¡unpleasant¡¡taste¡¡in¡¡all¡¡cases¡¡when¡¡the¡¡alcoholic¡¡ferment¡¡properly¡¡so¡¡called¡¡is¡¡not¡¡mixed¡¡with¡¡foreign¡¡ferments£»¡¡that¡¡it¡¡is¡¡the¡¡same¡¡in¡¡the¡¡case¡¡of¡¡wort£»¡¡and¡¡that¡¡wort£»¡¡liable¡¡to¡¡changes¡¡as¡¡it¡¡is£»¡¡can¡¡be¡¡preserved¡¡unaltered¡¡if¡¡it¡¡is¡¡kept¡¡from¡¡those¡¡microscopic¡¡parasites¡¡which¡¡find¡¡in¡¡it¡¡a¡¡suitable¡¡nourishment¡¡and¡¡a¡¡field¡¡for¡¡growth¡£

¡¨The¡¡employment¡¡of¡¡this¡¡second¡¡method¡¡has£»¡¡moreover£»¡¡the¡¡advantage¡¡of¡¡proving¡¡with¡¡certainty¡¡the¡¡proposition¡¡that¡¡I¡¡advanced¡¡at¡¡firstnamely£»¡¡that¡¡the¡¡germs¡¡of¡¡these¡¡organisms¡¡are¡¡derived¡¡from¡¡the¡¡dust¡¡of¡¡the¡¡atmosphere£»¡¡carried¡¡about¡¡and¡¡deposited¡¡upon¡¡all¡¡objects£»¡¡or¡¡scattered¡¡over¡¡the¡¡utensils¡¡and¡¡the¡¡materials¡¡used¡¡in¡¡a¡¡brewery¡­materials¡¡naturally¡¡charged¡¡with¡¡microscopic¡¡germs£»¡¡and¡¡which¡¡the¡¡various¡¡operations¡¡in¡¡the¡¡store¡­rooms¡¡and¡¡the¡¡malt¡­house¡¡may¡¡multiply¡¡indefinitely¡£

¡¨Let¡¡us¡¡take¡¡a¡¡glass¡¡flask¡¡with¡¡a¡¡long¡¡neck¡¡of¡¡from¡¡two¡¡hundred¡¡and¡¡fifty¡¡to¡¡three¡¡hundred¡¡cubic¡¡centimetres¡¡capacity£»¡¡and¡¡place¡¡in¡¡it¡¡some¡¡wort£»¡¡with¡¡or¡¡without¡¡hops£»¡¡and¡¡then¡¡in¡¡the¡¡flame¡¡of¡¡a¡¡lamp¡¡draw¡¡out¡¡the¡¡neck¡¡of¡¡the¡¡flask¡¡to¡¡a¡¡fine¡¡point£»¡¡afterwards¡¡heating¡¡the¡¡liquid¡¡until¡¡the¡¡steam¡¡comes¡¡out¡¡of¡¡the¡¡end¡¡of¡¡the¡¡neck¡£¡¡It¡¡can¡¡then¡¡be¡¡allowed¡¡to¡¡cool¡¡without¡¡any¡¡other¡¡precautions£»¡¡but¡¡for¡¡additional¡¡safety¡¡there¡¡can¡¡be¡¡introduced¡¡into¡¡the¡¡little¡¡point¡¡a¡¡small¡¡wad¡¡of¡¡asbestos¡¡at¡¡the¡¡moment¡¡that¡¡the¡¡flame¡¡is¡¡withdrawn¡¡from¡¡beneath¡¡the¡¡flask¡£¡¡¡¡Before¡¡thus¡¡placing¡¡the¡¡asbestos¡¡it¡¡also¡¡can¡¡be¡¡passed¡¡through¡¡the¡¡flame£»¡¡as¡¡well¡¡as¡¡after¡¡it¡¡has¡¡been¡¡put¡¡into¡¡the¡¡end¡¡of¡¡the¡¡tube¡£¡¡The¡¡air¡¡which¡¡then¡¡first¡¡re¡­enters¡¡the¡¡flask¡¡will¡¡thus¡¡come¡¡into¡¡contact¡¡with¡¡the¡¡heated¡¡glass¡¡and¡¡the¡¡heated¡¡liquid£»¡¡so¡¡as

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