168 "DISEASES" OF BEER, 



mentioned above. In the place of the casks with the com- 

 paratively deep layers of liquid, he employed shallow vats, in 

 which the liquid presented a large surface, and on this he 

 sowed a small portion of a film-growth from a previous 

 fermentation. Under these conditions the whole of the 

 alcohol contained in the wine will, as a rule, be converted into 

 vinegar within a few days. The vat is then cleaned, and a 

 new fermentation started in the same manner. With this 

 method the process is quicker than with that described above, 

 and the eels are avoided ; nevertheless, it has acquired no 

 application. In France the old slow method, especially the 

 form known as the Orleans process, is still always employed, 

 whilst that in vogue in other countries is almost exclusively 

 the new German quick process (Schnellessigfabrikation). It 

 would, however, be out of place here to further discuss the 

 advantages and defects of the various methods of manufac- 

 ture. 



Pasteur regarded the bacterial growth mentioned as con- 

 sisting of a single species. In 1879 I showed that it contained 

 two very distinctly different species, and one of these I named 

 Mycoderma Pasteur ianurn, after the famous French savant. 

 Zopf and other bacteriologists subsequently changed the 

 specific name to Bacterium. The number of species has lately 

 been further increased by recent investigations, conducted 

 partly by myself and partly by others. Amongst these acetic 

 acid bacteria, there are several, the activity of which is dis- 

 tinctly different, and it is, therefore, probable that a similar 

 reform will some day be introduced in the manufacture of 

 vinegar, such as I succeeded in effecting in the brewing 

 industry namely, the employment of a pure culture of a 

 systematically selected species. As yet, however, nothing 

 has been done in this direction, and the process is still carried 

 on hap-hazard. 



The investigations of Pasteur, and of those before him, 

 thus established the fact that there are different micro- 



