]^E\v York Agricultural Experiment Station. 313 



a careful revision of work published in previous bulletins of this 

 laboratory with material extensions of the line of investigation. 



Two compounds of casein and calcium have been generally recog- 

 nized, one containing about 2.50 per ct. CaO (1.78 per ct. Ca), and 

 the other about 1 .50 per ct. CaO (1 .07 per ct. Ca). We have found, 

 in addition, two others, one containing about 0.31 per ct. CaO 

 (0.22 per ct. Ca), and the other double this amount. Corresponding 

 compounds are shown in our work to be formed by paracasein with 

 calcium, and also by both casein and paracasein with ammonium, 

 sodium, potassium, barium and strontium. A study of the methods 

 of preparation and of the properties of these compounds is given in 

 this publication; the ground covered is embraced under the following 

 outline : 



Part I. Casein and some of its compounds. 



1. Method of preparing ash-free casein. 



2. Preparation and composition of basic calcium 



caseinate. 



3. Preparation and composition of unsaturated or acid 



caseinates. 



4. Valency of casein molecule and the molecular 



weight of casein. 



Part II. Paracasein and some of its compounds. 



1. Method of preparing ash-free paracasein. 



2. Preparation and composition of basic calcium para- 



caseinate. 



3. Preparation and composition of unsaturated or acid 



paracaseinates. 



4. Valency of paracasein molecule and the molecular 



weight of paracasein. 



5. Action of rennet-enzj'm on casein. 



Part III. Composition of brine-soluble compound in cheese. 



1. Brine-soluble compound formed in cheese-making. 

 . 2. Identity of brine-soluble compound and mono- 

 calcium paracaseinate. 



