122 M. Pasteur on Fermentation. 
Cagniard Latour showed. The translucent globules without 
granular contents gemmate most rapidly; there are more gra- 
nulations in proportion as the globule is older, less active, and 
less capable of gemmation. 
Mitscherlich supposed these globules to burst and discharge 
their granules, dispersing seminules in the liquid, which increase 
and become globules of ordmary yeast. Pasteur does not agree 
with this. 
It has been usually thought that, in the fermentation of solu- 
tion of sugar, the ferment, far from being destroyed, is developed 
by gemmation ; a close examination has shown the author that, 
in the fermentation of sugar in the presence of albuminous sub- 
stances, neither more nor less yeast is produced than when the fer- 
mentation takes place with pure solution of sugar, 
In all cases of the fermentation of pure solution of sugar, the 
weight of nitrogenous matter dissolved in the fermented liquid, 
added to the weight of the yeast, perceptibly exceeds the total 
weight of the original yeast. The increase amounts from 1:2 to 
1‘5 per cent. of the weight of the sugar. 
The disappearance of the yeast in certain cases is merely ap- 
parent. less yeast is obtaimed than was taken for fermentation 
because the quantity dissolved is greater than the weight of the 
new globules which are formed. In the fermentation of solutions 
of sugar containing albuminous matters, about 1 per cent. (of 
- the sugar) of yeast and soluble products is formed, and therefore 
a little less than in working with yeast already formed, and with 
pure solution of sugar. 
Hence the result is the same whether albuminous substances 
are present or not; the small difference observed arises doubt- 
less from the fact that the globules, formed in a medium where 
the nitrogenized aliment is in excess, are more active, and for the 
same weight decompose more sugar than those formed in a 
medium poor in mineral or nitrogenized aliments. 
Hence yeast, placed in solution of sugar, lives at the expense 
of the sugar and of its nitrogenous matter, which is dissolved or 
which becomes soluble from the changes taking place during 
fermentation between the principles which it contains. Fermen- 
tations which take place in the presence of excess of sugar are 
virtually of indefinite duration. This is readily conceived, for 
there is no destruction of nitrogenized matter; only displace- 
ments or modifications of this substance occur; and it remains 
in the complex state in which we are accustomed to meet with it 
in these products. ‘The soluble part of the nitrogenous matter 
becomes partially fixed in the globules in an insoluble state. 
But the power of organization which these globules possess is 
such that the old globules can yield their nitrogenized matter in 
