88 LOUIS PASTEUR. 



The argument appeared conclusive. How, in fact, 

 could we understand the production of a plant con- 

 taining within itself nitrogen and mineral elements 

 which was nevertheless to be nourished by water and 

 alcohol. 



' You do not take into account,' replied Pasteur, 

 ' the nature of the water which serves to dilute your 

 alcohol. This water, like all ordinary waters, even 

 the purest, contains salts of ammonia and mineral 

 matters which are capable of nourishing the plant. 

 Finally, you have not rightly examined with the micro- 

 scope the surface of the shavings, otherwise you would 

 have seen the little particles of the mycoderma aceti 

 united, in some cases, to a thin film which can even be 

 lifted up. I propose to you, moreover, to send to the 

 Academic Commission charged with the decision of the 

 debate, some shavings that you have obtained yourself 

 in the manufactory at Munich, and in the presence of 

 its director. I will undertake to prove before the mem- 

 bers of the commission the presence of the mycoderm 

 on the surface of these shavings.' 



Liebig did not accept this challenge. To-day the 

 question is decided. 



