THEORY OF FERMENTATION 373 



to this: Licbig denied that the ferment was capable of de- 

 velopment in a saccharine mineral medium, whilst we assert- 

 ed that this development did actually take place, and was 

 comparatively easy to prove. In 1871 we replied to M. Lie- 

 big before the Paris Academy of Sciences in a Note, in 

 which we offered to prepare in a mineral medium, in the 

 presence of a commission to be chosen for the purpose, as 

 great a weight of ferment as Liebig could reasonably de- 

 mand/ We were bolder than we should, perhaps, have been 

 in 1860; the reason was that our knowledge of the subject 

 had been strengthened by ten years of renewed research. 

 Liebig did not accept our proposal, nor did he even reply to 

 our Note. Up to the time of his death, which took place on 

 April i8th, 1873, he wrote nothing more on the subject.* 



When we published, in 1860, 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, especially 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 modification produced in the original 



T PASTEU, Comptes rendus dt I'Acadtmit dts Scitncts. vol. Ixxiii., 

 p. 1419. 1871. 



In his Mtmoir of 1870, Liebig made a remarkable admission: M My 

 late friend Pelouze." be says, " had communicated to me nine years ago 

 certain results of M. Pasteur's researches on fermentation. I told him 

 that just then I was not disposed to alter my opinion on the cause of 

 fermentation, and that if it were possible, bv means of ammonia, to pro* 

 duce or multiply the yeast in fermenting liquors, industry would soon 

 avail itself of the fact, and that I would wait to see if it did so; up to 

 the present time, however, there had not been the least change in the 

 manufacture of yeast." We do not know what M. Pelouze's reply was; 

 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 regarded 

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

 by the undoubted testimony of very distinpiiNhed practical men, notably 

 by that of M. Pezeyre, director of distilleries that upon this point *! 

 Liebig was mistaken. 



