STUDIES ON FERMENTATION. 315 



proved that it is possible for all organized ferments, properly 

 so called, to spring up and multiply from their respective germs, 

 sown, whether consciously or by accident, in a mineral medium 

 free from organic and nitrogenous matters other than ammonia, 

 in which medium the fermentable matter alone is adapted to 

 provide the ferment with whatever carbon enters into its com- 

 position, from that time forward the theories of Liebig, as well 

 as that of Berzelius, which M. E-obin formerly defended, have 

 had to give place to others more in harmony with facts. We 

 trust that the day will come when M. Robin will likev/ise 

 acknowledge that he has been in error on the subject of the 

 doctrine of spontaneous generation, which he continues to 

 affirm, without adducing any direct proofs in sujDport of it, at 

 the end of the article to which we have been here replying. 



We have devoted the greater part of this chapter to the 

 establishing with all possible exactness the extremely important 

 physiological fact of life without air, and its correlation to the 

 phenomena of fermentations properly so called — that is to say, 

 of those which are due to the presence of microscopic cellular 

 organisms. This is the chief basis of the new theory that we 

 propose for the explanation of these phenomena. The details 

 into which we have entered were indispensable on account of the 

 novelty of the subject no less than on account of the necessity 

 we were under of combating the criticisms of the two German 

 naturalists, Drs. Oscar Brefeld and Traube, whose works had cast 

 some doubts on the correctness of the facts upon which we had 

 based the preceding propositions. We have much pleasure in 

 adding that at the very moment when we were revising the 

 proofs of this chapter, we received from M. Brefeld an essay, 

 dated from Berlin, January, 1S76, in which, after describing 

 his later experimental researches, he owns with praiseworthy 

 frankness that Dr. Traube and he were both of them mistaken. 

 Life without air is now a proposition which he accepts as per- 

 fectly demonstrated. He has witnessed it in the case of mucor 

 racemosus, and has also verified it in the case of yeast. '' If," 

 he says, " after the results of my previous researches, which 1 



