78 MICROBES, FERMENTS, AND MOULDS. 



remains buried through the winter as a dormant 

 spore, in order to return to the same fruit when it 

 has ripened in summer. It can only be borne 

 through the air when the ground is completely dried 



In the same way, the fe r ments of wine, after 

 having passed through the bodies of men and animals, 

 pass the winter on the dungheap. This revelation 

 may not be pleasing to drunkards, but it will not 

 surprise those who are acquainted with the habits of 

 cryptogams in general, and of fungi in particular. 

 Brefeld has found these ferments during the winter, 

 especially in the excrement of herbivorous animals, 

 and on the dungheap. 



The manufacture of wine is too well known to 

 require description ; we need only remind our readers 

 that alcoholic fermentation essentially consists in the 

 transformation of glucose, or grape-sugar, into alcohol 

 and carbonic acid. The latter, given off in the form 

 of gas, produces the ebullition or effervescence which 

 characterizes fermentation, and to which its name is 

 due. Sugar or glucose is, therefore, the essential 

 nutriment of all yeast-plants, and the indispensable 

 element of these fermentations, of cider, beer, and all 

 fermented liquors, as well as of wine. 



IV. BEER-YEAST. 



The yeast of beer, or Sacch. cerevisice, was the 

 earliest known and the most carefully observed of 



