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 ferments 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. Brerr-YEAST. 
The yeast of beer, or Sacch. cerevisie, was the 
earliest known and the most carefully observed of 
