1 64 "DISEASES" OF BEER, 



we find the first indications as to how such a disease can 

 occur. He did not, however, make use of the term disease, 

 and neither did it occur to him to make any practical 

 application of his investigations. 



The same applies also to Turpin. The latter published 

 in 1838, a memoir* in which he described just as Kiitzing 

 did not only alcoholic and acetic ferments, but also several 

 other micro-organisms. The main result at which he arrived 

 is given (p. 134) in the following proposition: "No decom- 

 position of sugar, no fermentation without the physiological 

 activity of vegetation." Thus even at that time it was 

 known that there are different micro-organisms which bring 

 about different fermentations ; but a clearer understanding 

 of these relationships was wanting, and both Kiitzing and 

 Turpin held quite wrong views regarding the origin of the 

 microscopic organisms. 



\~Xgainst the experiments of Schulze and Schwann men- 

 tioned above, the objection could still be raised that the air 

 which was allowed to enter their flasks, had been previously 

 submitted to such a violent treatment in Schulze's experi- 

 ments by washing with sulphuric acid, and in Schwann's by 

 heat that it was possibly altered in such a way that, for 

 this reason alone, the dead matter was unable to enter into 

 life. This argument was answered by the beautiful experi- 

 ments which Schroder and Dusch conducted in 1854. The 

 method of experimenting adopted by these investigators 

 was the same as in the preceding cases, except that a 

 cotton-wool filter was attached to one of the tubes passing 

 through the stopper. The air entering the flask after its 

 contents had been boiled, was made to pass through this 

 filter ; in this case, the purification of the air was, therefore, 

 effected by filtration. They chose cotton-wool as filtering 

 medium " because " as they stated, " as is known, it is able to 



* Turpin, ' Memoire sur la cause et les effets de la fermentation alcoolique et 

 aceteuse. Paris, Lu a PAcademie, 1838.' 



