STUDIES ON FERMENTATION. 119 



And thus, as I said a little ago, speaking of these cells, they 

 often manifest the first signs of their budding in a few 

 seconds. 



In our preceding remarks we have expressly assumed that 

 there are many kinds of alcoholic ferment. This is, beyond 

 doubt, the case, as we have given incontestable proofs, first in 

 1862, in the BaUetin de la Societe chimiqne of Paris, and later 

 on, in 1864 and 1866, in a Note in the Comptes rendus, on 

 the diseases of wines, as well as in our " Studies on Wine." 

 Moreover, we know that brewers have long recognized two 

 distinct methods of fermentation — " high " fermentation and 

 " low " fermentation — and two corresponding yeasts. It is 

 true that the differences presented by these fermentations were 

 believed to be caused by the different conditions under which 

 they took place, and that it was supposed that we might change 

 " high " yeast into " low " 3'east, or inversely, by subjecting the 

 first to a low temperature, or the second to a high one. In our 

 observations of 1862, which we have just mentioned, we dis- 

 covered that must gives rise to several yeasts ; that the ferment 

 of " high " beer cannot develop except with great difficulty in 

 must, whilst one of the ferments of the grape grows rapidly 

 and luxuriantly in wort ; that it is easy to isolate the smallest 

 of the ferments of the grape from its congeners, by subjecting 

 filtered must to fermentation ; and finally, that the secondary 

 fermentations of wines which remain sweet furnish a remark- 

 able ferment, very diS'erent in aspect to the ferment of beer. 



We have not given specific names to these different fer- 

 ments, any more than we have to the other microscopic 

 organisms which we have had occasion to study. This was 

 not from any disregard for names, but from a constant fear 

 that, since the physiological functions of these minute forms 

 was the exclusive object of our study, we might be led to 

 attach too much importance to exterior characters. We have 

 often found that forms, having nothing apparently in common, 

 belong to one and the same species, whilst similarity of form 

 may associate species far apart. We shall give some fresh 



