Pasteur* 's Researches on Putrefaction. 103 



bring them back to the simple condition of binary compounds, 

 water, ammonia, and carbonic acid." 



" We have yet to distinguish the very remarkable case in 

 which the putrescible liquid forms a layer of slight thickness 

 with easy access to atmospheric air. I shall demonstrate expe- 

 rimentally that both putrefaction and fermentation may be 

 absolutely prevented, and that the organic matter will yield 

 only to the operation of combustion." 



" Such are the results of putrefaction effected with free 

 contact with the atmosphere. On the contrary, in the case of 

 putrefaction under shelter from the air, the products of the 

 doubling* of the putrescible matter remain unchanged. This 

 is what I meant when I said that putrefaction in contact with 

 air is a phenomenon, if not always more rapid, at least more 

 complete, more destructive of organic matter, than putrefaction 

 under shelter from air. In order to be better understood I 

 shall cite some examples. Let us putrefy — I employ the word 

 designedly in this instance as a synonym of ferment — let us 

 putrefy lactate of lime sheltered from air. The vibrion-ferments 

 will transform the lactate into several products, one of which is 

 always butyrate of lime. This new compound, indecomposable 

 by the vibrio which provoked its formation, will remain inde- 

 finitely in the liquid without any change. But repeat the ope- 

 ration in contact with air. As fast as the vibrion-ferments act 

 in the interior of the liquid, the pellicle on the surface gradually 

 and completely burns the butyrate. If the fermentation is very 

 active this combustion is arrested, but entirely because the car- 

 bonic acid that is disengaged hinders the arrival of atmospheric 

 air. The phenomenon recommences as soon as the fermentation 

 is finished or lessened in rapidity. It is precisely the same if we 

 cause a naturally sweet liquid to ferment under shelter from 

 air, the liquid is charged with alcohol almost indestructible ; 

 while if we operate with contact of air, the alcohol after being- 

 acetified is burnt and transformed entirely into water and 

 carbonic acid. Then the vibrions appear, and in their suite 

 putrefaction, when the liquid only contains water and nitro- 

 genous matter. At length in their turn the vibrions and the 

 products of putrefaction are burnt by the bacteriums or the 

 mucors, of which the last survivors incite the combustion of 

 their predecessors, and thus is accomplished the return of the 

 organized matter to the atmosphere and to the mineral 

 kingdom.'" » 



"Let us now consider the putrefaction of solid bodies. 

 I have recently shown that the body of an animal is, under 



* " De doublement cle la maliere putrescible." Pasteur means the products of 

 the putrefactive fermentation, which he has described as complex, though more 

 simple than the original substances. 



