328 STUDIES ON f?:rmentation. 



his mode of viewing the question.* Aftei' deep consideration 

 he pronounces this experiment to be inexact, and the result ill- 

 founded. Liebig, however, was not one to reject a fact without 

 grave reasons for his doing so, or with the sole object of evading 

 a troublesome discussion. " I have repeated this experiment," 

 he says, " a great number of times, with the greatest possible 

 care, and have obtained the same results as M. Pasteur, except- 

 ing as regards the formation and increase of the ferment." It 

 was, however, the formation and increase of the ferment that 

 constituted the point of the experiment. Our discussion was, 

 therefore, distinctly limited to this : Liebig denied that the 

 ferment was capable of development in a saccharine mineral 

 medium, whilst we asserted that this development did actually 

 take place, and was comparatively easy to prove. In 1871 we 

 replied to M. Liebig 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 demand. f 

 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, Avhich took place on April 18th, 1873, he 

 wrote nothing more on the subject. + 



* See oiir Memoir of ISGO {AnnaJes de Chimie et de Physique, vol. Iviii. 

 p. 61, and following, and especially pp. 69 and 70, where the details of 

 the experiment will be found. 



t Pasteur, Comjdcs rcndus de V Academie des Sciences, vol. Ixxiii. 

 p. 1419, 1S71. 



J In his Memoir of 1870, Liebig has made a remarkable admission: 

 "My late friend Pelouze," he saj'S, "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 by means of ammonia 

 to produce or multiply the yeast in fermenting Kquors, 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 has not been the least change in the 

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



