1G8 TtKI'ilUr OF TIIK (JllKinCAL DbPAK'niENT OF TIIK 



Mr. L. A. Rogers, Assistant Daetoviologist, lias donp much of 

 the routine work connected with the bacteriological examina- 

 tions. Mr. J. A. Le Clerc and Mr. A. J. Patten have rendered 

 efficient assistance in some of the chemical work. 



11. HISTOEICAL OUTLINE. 



The following outline of the work previously done in relation 

 to cheese ripening covers only those features that relate to the 

 special problems we have been studying. 



In 1887, Benecke,^ in discussing the r-jle of bacteria in cheese 

 ripening, stated that, while they probably caused such changes, 

 yet the ripening might really be due to the activity of some unor- 

 ganized ferment. He pointed out that, if bactf^'ia are not essen- 

 tial to cheese ripening, this fact could be made clear by the 

 preparation of cheese under conditions which would exclude 

 bacterial activity. Acting on this suggestion Adametz^ pre- 

 pared a number of Hauskiise, a form of soft cheese, in the nor- 

 mal way, except that he added various disinfectants to the milk 

 or to the curd derived from it. 



When cheese made with the addition of kreolin or of thymole, 

 were examined bacteriologically, they were pronounced sterile; 

 but even when kept for double the normal length of time, they 

 did not take on the appearance of ripened cheese. His experi- 

 ments with salicylic acid, oxalic acid and with vapors of carbon 

 disulphide and iodine were less satisfactory in repressing the 

 microorganisms in the cheese, but these agents seemed to hold 

 back the ripening in proportion as they inhibited the activity of 

 germ life. 



(Cheese investigators quite generally accepted these results as 

 settling the point raised by Beupcke, and during the succeeding 

 ten years the work on cheese ripening was based upon the 

 theory of germ action. 



The phenomena of ripening in cheese may be divided into two 

 classes, (1) the chemical decomposition of casein and (2) the lor- 



•Benecke. Cent. f. Bak., I Abt.. I:n2l (ISST). 



»Adametz. Thiel's Laudwiitschaftliche Jabib., 18:227 (1889). 



