DAIRY FARMING DAIRYING. 



705 



which acidify and peptonize milk. To the last class belong the cocci previously 

 isolated by the author and the bacillus uoted above. 



The presence of anaerobic bacteria in normal milk and their relation to 

 the ripening - of cheese, A Rodklla (Centbl. Bakt. u. Par., .'. Abt., 13 (1904), -Vox. 

 16-17, pp. 504-513; 19-20, />/>. 589-604). — The greater part of this article is devoted 

 to a description of methods for isolating and growing anaerobic bacteria. In earlier 

 articles the author lias shown that anaerobic bacteria of the butyric-acid type are 

 present in cheese. In the present articles he reports that such bacteria are regularly 

 present in 0.1 cc. samples of milk from which he concludes that in 1 gm. of cheese 

 their number must exceed 100. 



The regular occurrence of anaerobic bacteria in cheese, and the fact that such bac- 

 teria are capable of producing from casein and other proteids a cheese-like odor, are 

 advanced by the author in support of his view that anaerobic bacteria take part in 

 the ripening of Emmenthal and other kinds of cheese. 



Biological studies of the cheese-ripening process with special reference to 

 the volatile fatty acids, O. Jensen (Landw. Jahrb. Schweiz, 18 (1904), No. 8, pp. 

 319-405; Ann. Agr. Suisse, 5 (1904), No. 7, pp. 229-326; Centbl. Bakt. u. Par., 2. 

 Abt., 13 (1904), Nus. 5-7, pp. 161-170; 9-11, pp. 291-306; 13-14, pp. 428-439; 16-17, 

 pp. 514-527; 19-20, pp. 604-615; 22-23, pp. 687-7').',,- .",. />/>. 753-765). —The following 

 table summarizes some of the analytical data obtained by the author in his examina- 

 tions of different kinds of cheese: 



Volatile fatty acids in cheese, in grams per kilogram. 



The greater portion, at least, of the caproic and butyric acids in rennet cheese is 

 considered as coming from the fat. Acetic acid was present in all the kinds of 

 cheese examined, as was also formic acid, although the quantity of the latter was 

 often too small to determine. As these 2 acids are formed by all the ferments inves- 

 tigated, their origin in cheese is easily explainable. They were present in only 

 small quantities in those kinds of cheese in which molds play the principal role in 

 ripening. In all the other kinds of cheese, propionic acid was present and often in 

 such large quantities as to constitute the principal acid. 



The origin of so much propionic acid in cheese is not considered clear. While 

 most of the ferments produce propionic acid in cultures, the quantity is always much 

 less than that of acetic acid. In cheese containing large quantities of volatile fatty 



