1913.] 



Phenomena of '" Clot" Formations. 



463 



such solutions can cause a relatively large error in the solubility determination. 

 Better results would also probably have been obtained had it been feasible 

 to avoid the use of glass vessels. In spite, however, of all these known 

 inaccuracies, the deviations from the absolutely correct figures are so small 

 compared with the changes produced by submitting caseinogen to various 

 treatments, that the lack of rigidity in the experiments does not materially 

 affect the conclusions drawn from the results ; it accounts for the small 

 irregularities to be noticed in the various tables of results. 



The nitrogen was estimated in 5 c.c. of the filtrate by Kjeldahl's method. 

 The number of cubic centimetres of N/10 acid required to neutralise the 

 ammonia produced will, throughout this paper, for the sake of brevity, be 

 designated simply the solubility of the preparation. 



Differences in the Solubility in Alkalis of Various Preparations. 



The earliest experiments indicated that great differences existed between 

 the various preparations employed. 



A sample of a Ehenania caseinogen showed a solubility in \ sat. Ca(OH) 2 

 of 5T, whereas the solubility of the preparation prepared by the modification 

 of Hammarsten's method mentioned above was 2T2. Sodium hydroxide 

 solutions dissolve approximately the same amount of substance as the 

 equimolar (and not equinormal) calcium hydroxide solutions. In this respect 

 caseinogen behaves like other proteins, such as edestin and globulin. 



Attempts were then made to account for the differences in the behaviour of 

 the various preparations. A series of products was made from milk, by the 

 method already described, but instead of purifying the precipitated caseinogen 

 by dissolving it in sodium hydroxide, it was treated with other alkalis 

 (normal solutions), from the solutions in which it was precipitated by acetic 

 acid ; the procedure was exactly the same as when sodium hydroxide was 

 employed. 



No marked difference was found in the solubility of the various prepara- 

 tions thus obtained. 



Nevertheless, the numbers found are of quite a different order to the 

 solubility of the Ehenania preparation (5 - l). The effect of the treatment of 

 the Ehenania caseinogen by alkali was next investigated. This was dissolved 

 in normal alkali, reprecipitated, and treated by the general routine process 

 (alcohol, ether, etc.). The preparation thus obtained was now much more 

 soluble in \ sat. Ca(OH) 2 , viz., 21*1, i.e. it was of the same order as that of 

 the preparations made in the laboratory. 



Attempts were next made to ascertain the reason of the great differences 



