STUDIES ON FERMENTATION. 329 



When we published, in I860, the details of the experiment 

 in question, we pointed out at some length the difficulties of 

 conducting it successfully, and the possible causes of failure. 

 We called attention particularly to the fact that saccharine 

 mineral media are much more suited for the nutrition of bacteria, 

 lactic ferment, and other lowly forms, than they are to that of 

 yeast, and in consequence readily become filled with various 

 organisms from the spontaneous growth of germs derived from 

 the particles of dust floating in the atmosphere. The reason 

 why we do not observe the growth of alcoholic ferments, espe- 

 cially at the commencement of the experiments, is because of 

 the unsuitableness of those media for the life of yeast. The 

 latter may, nevertheless, form in them subsequent to this 

 development of other organized forms, by reason of the modi- 

 fication produced in the original mineral medium by the albu- 

 minous matters that they introduce into it. It is interesting to 

 peruse, in our Memoir of 1860, certain facts of the same kind 

 relating to fermentation by means of albumens — that of the 

 blood, for example, from which, we may mention incidentally, 

 we were led to infer the existence of several distinct albumens 

 in the serum, a conclusion which, since then, has been confirmed 

 by various observers, notably by M. Bechamp. Now, in his 

 experiments on fermentation in sweetened water, with yeast-ash 

 and a salt of ammonia, there is no doubt that Liebig had failed 

 to avoid those difficulties which are entailed by the spontaneous 

 growth of other organisms than yeast. Moreover, it is possible 

 that, to have established the certainty of this result, Liebig 

 should have had recourse to a closer microscopical observation 

 than from certain passages in his Memoir he seems to have 



but it is not difficult to conceive so sagacious an observer remarking to 

 his illustrious friend, that the possibility of deriving pecuniary advantage 

 from the wide application of a new scientific fact had never been re- 

 garded as the criterion of the exactness of that fact. We could prove, 

 moreover, by the undoubted testimony of very distinguished practical 

 men, notably by that of M. Pezeyre, director of distilleries, that upon 

 this point also Liebig was mistaken. 



