332 Report of the Department of Chemistry of the 



These results indicate the formation of two sets of compounds 

 when paracasein is dissolved in a hydroxide of calcium, strontium 

 or barium and this solution is neutralized with acid under the condi- 

 tions of our experiments. One set of compounds contains twice as 

 much base as the other, corresponding to the two sets of casein 

 compounds. Additional details are discussed below : 



(1) In the di-basic compounds, the results show that 1 gram of 

 paracasein requires between 4.5x10'* and 4.55x10* gram equiv- 

 alents of hydroxide of calcium, strontium or barium to form a com- 

 pound which is soluble in pure water. These compounds are easily 

 precipitated from their water solutions by a minute amount of a 

 soluble salt of calcium, strontium or barium. 



(2) In these di-basic compounds, 100 grams of paracasein com- 

 bine, approximately, (a) with 0.90 gram Ca (equal to 1.26 grams 

 CaO), (b) with 1.97 grams Sr (equal to 2.33 grams SrO), or (c) with 

 3.09 grams Ba (equal to 3.45 grams BaO). 



(3) It is indicated that, with the treatment described above, 

 1 gram of paracasein combines with about 2.3 x 10* gram equiva- 

 lents of the hydroxide of calcium, strontium or barium to form an 

 insoluble compound. These compounds are regarded as mono-basic 

 paracaseinates. 



(4) In these insoluble mono-basic paracaseinates, 100 grams of 

 paracasein combine, approximately, (a) with 0.46 gram Ca (equal 

 to 0.64 gram CaO), (b) with 1.01 grams Sr (equal to 1.19 grams 

 SrO), or (c) with 1.58 grams Ba (equal to 1.76 grams BaO). 



(5) Mono-basic paracaseinates of calcium, strontium and barium 

 are completely soluble in warm 5 per ct. solution of ammonium, 

 sodium or potassium chloride. This solubility is due to interchange 

 of bases, just as in the case of caseinates (p. 18); the reaction was 

 studied experimentally with paracaseinates and the same results 

 obtained as in case of the caseinates. 



(6) A comparison of the composition of the caseinates and para- 

 caseinates shows that twice as much base is present in paracaseinates 

 as in the corresponding caseinates. This is easily seen in the fol- 

 lowing table. 



Table XIV. — Comparison of Composition of Caseinates and Paracaseinates. 

 Amount of basic element combined with 100 gram^ of casein and paracasein. 



