STUDIES ON FERMENTATION. 145 



tlons will give some idea of what it is in the case of one of the 

 ferments of natural must. The temperature was between 12° C. 

 and 13° C. (55° F.). 



"On October 12, 1861, at ten o'clock in the morning, we 

 crushed some grapes, without filtering the juice that ran from 

 them; afterwards, at different times during the day, we examined 

 the juice under the microscope, until at last, although not before 

 seven o'clock in the evening, we detected a couple of cells, as 

 represented in Fig. 25, a. 



I t ^ t % \ 



a 

 Fig. 25. 



From that time we kept these contiguous cells constanth^ in 

 view. At 7.10 we saw them separate and remove to some little 

 distance from each other (Fig, 25, h). Between 7 and 7.30 we 

 saw, on each of these cells, a very minute bud originate and 

 grow little by little. These buds developed very near the point 

 of contact, where the disjunction had just taken place. By 

 7.45 the buds had increased greatly in size (Fig. 25, c). By 

 8 they had attained the size of the mother-cells. By 9 each 

 cell of each couple had put forth a new bud (Fig. 25, d). We did 

 not follow the multiplication of the cells any farther, having 

 seen that in the course of two hours two cellules had furnished 

 eight, including the two mother-cells. '^' * 



An increase like this, which would have been more rapid at a 

 temperature between 15° and 25° (59° and 77° F.), and still 

 more so between 25° and 30° (77° and 86° F.), may indeed seem 

 surprising. It is really, however, nothing to what sometimes 

 occurs. In choosing proper conditions of temperature and 

 medium, of state and nature of yeast, it has sometimes happened 

 that the bottom of a vessel has become covered with a white de- 

 posit of yeast cells, in the course of not more than five or six hours 



* Extract from a Note which I inserted in 1862 in the Bulletin de la 

 Societe chimique of Paris. 



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