FERMENTS, FERMENTATIONS, AND LIFE. 



UNTIL very lately, all fermentations were supposed to 

 be produced by the spontaneous decomposition of organic 

 matter within a fermentable liquid. It was said that on 

 contact with air this organic matter undergoes a special 

 change which gives it the character of leaven, and this was 

 regarded as an agent having the power of spreading decom- 

 posing movement. It is true, brewer's yeast had long been 

 well known ; the facts of its cellular composition and its 

 organization were familiar ; but no relation was recognized 

 between this organized condition and those phenomena of 

 fermentation produced by yeast in saccharine liquids, such 

 as grape-juice or the wort of ale. In the first few years of 

 this century Turpin, and afterward Cagniard-Latour, at- 

 tempted in vain to prove that such a relation existed ; it 

 was always denied that any thing else could be observed 

 in alcoholic fermentation than an operation resembling all 

 those slow decompositions that were classed among fer- 

 mentations. We have admitted, in our time, that alcoholic 

 fermentation, instead of being an exception, is on the con- 

 trary the very type of the phenomena we are treating of ; 

 that the yeast-cells, far from being unimportant, take an 

 essential part in it, and that in all fermentations whatever 

 there occur low organizations, microscopic corpuscles, more 

 or less analogous to those of yeast. At least this is the 

 first result of investigations carried on in the past fifteen 



