1913.] 



Phenomena of" Clot" Formations. 



467 



minutes, when the caseinogen had settled at the bottom of the precipitating 

 vessels, the supernatant liquid was syphoned off', this process being accom- 

 plished in as short a time as possible. The precipitate was then washed 

 twice by decantation with several times its volume of ice-cold water. It was 

 then treated with graded strengths of alcohol, up to absolute alcohol, then 

 with ether, and finally air-dried. A very fine light power was thus obtained, 

 which was considerably more soluble in £ sat. Ga(OH) 2 than any of the 

 preparations obtained by the ordinary Hammarsten method, when the 

 precautions described above were not observed. 



Whereas the solubility of the Hammarsten preparations in lime water 

 varied as a rule (and the reason of these variations is now obvious) between 

 20 and 26, that of the new preparation was about 35. The solubilities of a 

 large number of preparations obtained by the new method were determined ; 

 the majority of them showed a solubility in £ sat. Ca(OH) 2 which varied but 

 slightly from that given. 



Furthermore, the solutions thus obtained both in \ sat. Ca(OH) 2 and the 

 equimolar sodium hydroxide solution, especially that in lime water, had an 

 opaque milky appearance which retained the opacity even after dilution 

 with several volumes of water, which is in marked contrast to the 

 opalescent solutions obtained with the ordinary commercial preparations. 



The Lability of the "Natural" Caseinogen. 



The factors influencing the changes in the " natural " caseinogen were next 

 investigated. 



Effect of Acids. 



Ten-gramme samples of the " natural " caseinogen were allowed to stand 

 with 100 c.c. of a 0*l-per-cent. acetic acid solution, which is about the 

 strength of the acid in which the original precipitate is produced. The 

 samples were allowed to stand for varying times with the acid, then filtered, 

 washed with water, and repeatedly with alcohol, to remove the last traces 

 of acid. They were finally washed with ether and air-dried. The following 

 numbers indicate the solubilities in \ sat. Ca(OH) 2 after varying periods 

 of contact with 1/1000 acetic acid : — 



Original preparation 35"0 



After 1 hour with acid 27"3 



„ 2 hours „ 19-3 



„ 6 „ „ 15-5 



„ 24 „ „ 11-4 



