CAUSES OF RIPENING CHANGES 355 



which are most intimately connected with the chang- 

 ing qualities that appear in the process. As pre- 

 viously stated, the cheese-ripening process, considered 

 from a chemical standpoint, consists mainly in the 

 change of the complex protein, paracasein, as it exists 

 in cheese-curd, into a number of less complex com- 

 pounds. 



Many difficulties beset the experimental study of 

 cheese-ripening, some of which will be briefly noticed 

 later. One of the great difficulties in the past has 

 been a failure to recognize that there was more than 

 one agent at work in the process of cheese-ripening. 

 The investigator is always at a disadvantage when 

 his point of view is too narrow, since he inevitably 

 overlooks essential details, and interprets his results 

 within the narrow range of his vision. This truth has 

 been amply illustrated in the history of the investiga- 

 tion of the causes of -cheese-ripening, since many in- 

 vestigations were based upon the conception that only 

 one agent was the cause; and the object of the inves- 

 tigator was, unconsciously, not so much to find out 

 what the real cause might be as to show that the one 

 particular agency he had in mind was the actual and 

 sole cause. 



We shall not attempt to treat the subject in the 

 order of its historical development, but rather in the 

 order in which the different agencies become most 

 active in the ripening process. So far as our present 

 knowledge goes, the different agents taking part in 

 the change of the protein, paracasein, into simpler 

 proteins and protein-derived compounds are the fol- 

 lowing : 



I. Some acid, usually lactic. 



