202 Report of the Chemical Department of the 



rennet-extract slightly increased the proteolytic results in the 

 cheese. This cheese contained considerably less moisture than 55 

 or 57. 



(2) The use of 15 grams of commercial pepsin along with 

 rennet-extract produced very marked results. This is strikingly 

 evident in the fresh cheese, where we have 25 per ct. of the 

 nitrogen in the cheese present in the form of water-soluble com- 

 pounds, while in the case of experiment 55, in which rennet- 

 extract only was used, the amount of soluble nitrogen com- 

 pounds is less than 5 per ct. At the end of 3 months, we still 

 have much more of the soluble nitrogen compounds in 57, the 

 pepsin cheese, than we have in 55, the rennet-extract cheese, at 

 the end of 6 months. 



(3) In comparing the proteolytic factors in experiments 55 and 

 57, the conditions of work were such that the chief essential 

 difference was the presence of pepsin in the latter, though 57 

 contained more moisture than 55. The observed difference in 

 the chemical results could, therefore, be due only to pepsin, and 

 this would be particularly true of the results obtained in the 

 fresh cheese. 



action of rennet-enzyme and commercial pepsin on para- 

 casein dilactate. 



We have already given the results of our study relating to the 

 action of rennet-enzyme and of connnercial pepsin on casein in 

 milk and on casein monolactate, in the presence of chloroform. 

 We have studied the action of these two enzymes also on the 

 proteids of cheese made from pasteurized milk. We w'ill now 

 present the results of some work done in studying the action of 

 these same enzymes on paracasein dilactate. Paracasein mono- 

 lactate was extracted from several pounds of cheese by a 10 per 

 ct. solution of sodium chloride and this was treated with acid, 

 precipitating paracasein dilactate. Of this compound washed 

 free from salt, we placed 25 grams, suspended in water, in each 

 of several flasks and sterilized by heat. We then sterilized some 

 solution of pepsin and rennet-extract by treating with 0.5 per 

 ct. of formalin, containing 0.2 per ct. of formaldehyde. Accord- 



