CASEIN. 



TABLE IX. 



51 



It is seen that the results of Hammarsten, Chittenden and 

 Painter, and Ellenberger are in good agreement, while they 

 differ appreciably from the figures obtained by the last three 

 observers, who probably did not remove Storch's mucoid 

 protein so completely as the others. 



Hammarsten and Chittenden purified their casein by solution 

 in alkali and reprecipitation several times, finally treating with 

 alcohol and ether ; Bitthausen worked on the copper salt ; 

 and Lehmann used what he designated " genuine " casein, 

 which was separated from milk by the use of a porous plate. 



Casein behaves as a distinct polybasic acid ; it has also basic 

 properties, and combines with acids giving salts easily decom- 

 posed by water. The acid functions are much more strongly 

 marked than the basic ones. On hydrolysis it yields ultimately, 

 according to Fischer and others, especially Osborne, Guest, and 

 Foreman, the following (the estimations of leucine, glutamic 

 acid, tyrosine, lysine, arginine, and histidine are probably nearly 

 correct ; the other figures probably low) : 



Glycine, . 



Alanine, . 



Leucine, . 



Phenyl-alanine, 



Proline, 



Glutamic acid, 



Aspartio acid, 



Cystine, 



Serine, 



Oxy-proline, 



Tyrosine, . 



Lysine, 



Histidine, . 



Arginine, . 



Tryptophane, 



Ammonia, 



Cy stein, 



Amino-valeric acid, 



Glucosamine, 



Diamino-trioxy-dodecanoic acid, 



none 



1-5 

 10-5 



3-2 



6-7 

 21-8 



1-7 



0-065 



0-5 



1-5 



4-5 



5-95 



2-55 



4-84 



1-5 



1-61 

 none 



7-2 

 none 



0-75 



