352 SCIENCE AND PRACTICE OP CHEESE-MAKING 



much more rapidly in the early stages of ripening 

 than later. It is shown that, in the first 3 months 

 of the 18-month period of study, over 65 per cent 

 of the nitrogen was changed into the form of 

 water-soluble compounds. How can we explain 

 this observed fact that the rate of chemical change, as 

 measured by the formation of water-soluble ni- 

 trogen compounds, decreases as the age of cheese 

 increases? The most obvious explanation is asso- 

 ciated with the generally observed fact that in fer- 

 mentation changes the products of the process 

 weaken the action of the ferment, often inhibiting 

 it altogether (p. 286). In cheese, we have an ac- 

 cumulation of fermentation products in the form of 

 water-soluble protein and protein-derived compounds 

 and, apparently, they serve to diminish the action of 

 the agents that cause the changes. 



In this connection, it is interesting to notice that 

 the end-products, the amino acids and ammonia, 

 appear to exert a stronger influence than do the other 

 soluble protein compounds in decreasing the action of 

 the ripening agents. This is indicated by the fol- 

 lowing data : 



