PARANUCLEIN FROM CASEIN. 401 



transform the paranuclein compound with a high ash content, 

 i. e., paranuclein-calcium (or paranuclein-sodium), into a para- 

 nuclein containing only a very small proportion of ash and 

 readily giving off its entire phosphorus on ignition. The 

 reverse process the formation of a calcium compound of 

 paranuclein and the consequent cleavage of the phosphorus as 

 inorganic phosphorus on ignition is further demonstrated 

 by the following experiment. 



Preparation H A portion of preparation B was dissolved 

 in calcium hydroxide. After evaporation of the fluid to a 

 small volume, it was treated with absolute alcohol, and the 

 precipitate thus formed removed by filtration. Analysis of 

 this product, dried at 105 C., resulted as follows : 



Phosphorus found in the ash = 3.03%. 



SUMMARY. 



It is shown that the paranuclein obtained by digestion of 

 casein with pepsin-hydrochloric acid always contains a con- 

 siderable content of phosphorus in organic combination. The 

 results of previous investigators who found that the phos- 

 phorus recovered in the ash of their preparations was equiv- 

 alent to the total phosphorus content of the paranuclein, are 

 attributable to the high ash content of their products. When 

 the latter is avoided, and thus the formation of inorganic 

 phosphate during ignition is precluded, paranuclein invariably 

 yields over 2 per cent of organic phosphorus. 



In conclusion, it is my desire to express my indebtedness to 

 Professor Lafayette B. Mendel for many kind suggestions. 



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