New York Agricultural Experiment Station, 247 



another way, that we must have paracasein monolactate present 

 before we can have formed such compounds as caseoses, peptones 

 and amides. Starting with the casein of milk, we have in cheese- 

 curd and ripening cheese the following nitrogen compounds 

 formed in something like the following order: paracasein, para- 

 casein monolactate, paranuclein, caseoses, peptones, amido com- 

 pounds and ammonia compounds. The amounts of these dififer- 

 ent compounds and classes of compounds and their relations to 

 one another we shall study in some detail in the following pages. 



In the manufacture of the cheeses used in the work, we had 

 the skilful services of Mr. Geo. A. Smith. The general plan 

 was to follow the usual commercial methods employed in making 

 cheddar cheese. Where there was any departure from normal 

 methods, notice is called to it in connection with the discussion 

 or the analytical tables contained in the Appendix. The cheeses 

 were kept under known conditions during the curing process. 

 From 4 to 8 cheeses were made at a time from each separate lot 

 of milk, the amount of milk varying from 400 to 1200 pounds. 

 The cheeses were made in two sizes, 10 and 30 pounds. 



The chemical results obtained may be used to some extent as 

 standards of reference, so far as they represent normal cheddar 

 cheese under the conditions given. 



THE RELATION OF TIME TO THE CHEESE-RIPEN- 

 ING PROCESS. 

 An examination of the detailed analyses given in the Appendix 

 shows, in the case of every individual cheese, under all the con- 

 ditions studied, that there is a progressive change, resulting in an 

 increase of water-soluble nitrogen compounds as the cheese ad- 

 vances in age. As we shall point out later, the efifect of time as a 

 factor in cheese-ripening is modified by a variety of conditions. 

 For purpose of illustration, we will here give averages of the 

 results obtained under the various conditions employed. Each 

 analysis represents averages of the results obtained with 24 dif- 

 ferent cheeses, and they exhibit more fully than any other data 

 published within our knowledge the detailed chemical changes 

 that occur in the nitrogen compounds of cheese during the pro- 

 cess of ripening. 



