STUDIES ON FERMENTATION. 



189 



fourteen hours afterwards, an appreciable deposit of yeast had 

 formed, and some frothy patches appeared on the surface of 

 the liquid, showing that fermentation had set in. On May 



Tig. 40. 



1st we decanted the beer, substituting for it water sweetened 

 with 10 per cent, of sugar. On May 2nd we decanted the 

 sweetened water, and substituted a fresh quantity containing 

 the same percentage of sugar. On May 3rd, at mid-day, we 

 took some of the fermenting liquid from this flask and put it 

 into a flask of wort ; five hours after the introduction of the 

 ferment we made the sketch in question. The field is covered 

 with branching clusters, the groups being sketched exactly as 

 they occurred in the field. Their activity was due to the 

 condition of the ferment, and to the perfect fitness of the 

 nutritive medium for its vegetation. In sweetened water 

 the budding of the cells was considerably less active ; no branch- 

 ing groups of cells are to be found. Budding, nevertheless, 

 occurs to a considerable extent, but it is limited to one bud, 

 or two at the most, to each cell. Fermentation in pure 

 sweetened water is mostly correlative with the duration of 

 vital activity in the globules already formed. 



Let us next sufier our yeast to exhaust itself by keeping 

 it in a great excess of sweetened water for a very long time ; 

 we shall then be able to observe its process of revival, and 



