New York Agricultural Experiment Station. 265 



moisture serves to dilute the fermentation products and to that 

 extent to counteract their unfavorable effect. 



In ordinary cheese-ripening, there is a constant loss of mois- 

 ture and this serves to make more concentrated the fermentation 

 products which are increasing at the same time the moisture is 

 decreasing. Accordingly, after 3 to 6 months, difference in 

 moisture appears from the results of our work to exert a more 

 marked influence upon the increased formation of soluble nitro- 

 gen compounds than in the early stages of ripening. 



THE CHARACTER OF THE ACTION OF RENNET-EXTRACT. 



In Bulletin No. 233 of this Station, the work of others has been 

 confirmed in showing that the active constituent of rennet is a 

 peptic ferment and that the part performed in cheese-ripening by 

 rennet-extract is a peptic digestion, in which the chemical changes 

 are largely confined to the conversion of paracasein monolactate 

 into paranuclein, caseoses and peptones, only small amounts of 

 amides being formed. 



THE RELATION OF ACID IN CHEESE TO CHEESE-RIPENING. 



In Bulletin No. 203, page 240, of this Station, we called atten- 

 tion to the fact that presence of acid in cheese favors the action of 

 enzymes in the cheese-ripening process. In Bulletin No. 214, it 

 was shown that acid performs a specific function in the cheese- 

 making process, uniting with paracasein to form paracasein 

 monolactate. It was also shown that paracasein monolactate 

 appears to form the real starting point of the cheese- 

 ripening process, since we have been unable to obtain soluble 

 nitrogen compounds to any extent without the presence of para- 

 casein monolactate and since this compound decreases in amount 

 as soluble nitrogen compounds increase. 



From our work previously done, it appears that acid in cheese 

 is a prerequisite for its ripening. Additional work is required to 

 show the specific influence of different amounts of acid upon the 

 cheese-ripening process. 



In examining the detailed data given in the Appendix in 

 cheeses 41 A, B and D, which were kept at 12."^ F., it is noticeable 

 that the amount of paracasein monolactate increases until the 

 third month in the case of A and B and until the ninth month in 



