466 Mr. S. B. Schryver. Investigations on the [Mar. 6, 



From the above table it will be observed that caseinogen is changed by 

 simply heating with water at incubator temperature. The change proceeds 

 until a solubility denoted by the number 11 is attained. When this point 

 is attained further change appears to be very slow. At higher temperatures, 

 however, further changes are produced, and the caseinogen is converted into a 

 product which is no longer soluble in excess of sodium hydroxide. The 

 products obtained by the action of water at higher temperatures have not 

 been further investigated. 



In view of the fact that excess of casinogen preparation was always used 

 in the solubility estimations, and that consequently the saturated solutions of 

 caseinogenate were kept for some time in agitation with this excess, experi- 

 ments were carried out to ascertain how far adsorption phenomena influenced 

 the final equilibrium. For this purpose, 20 c.c. of saturated solutions of the 

 original preparation and a preparation which had been heated for three- 

 quarters of an hour with water at 75°, in \ sat. Ca(OH) 2) were rotated with 

 1| grm. of the various heated products for 17 hours. The mixtures were then 

 centrifuged and the nitrogen was estimated in 5 c.c. of the filtered supernatant 

 fluid. It was found that a small amount of the caseinogenate was thus 

 removed from solution. Thus in the case of the unheated caseinogenate 

 5 c.c. required, after Kjeldahlisation, about 20 c.c. N/10 acid to neutralise 

 the ammonia produced. Of the same preparation, after rotating with 

 various samples of heated products, 5 c.c. required 17'4-182 c.c. In 

 the case of the heated product, 5 c.c. of the caseinogenate were equivalent 

 to 10*0 c.c. of acid, and after rotation with the heated products, to 8-9 c.c. 

 of acid. There was no marked difference in the adsorption capacities of 

 the different heated products. Adsorption phenomena have therefore but 

 little influence on the comparative values of the numbers given in the above 

 table. 



The Preparation of " Natural " Caseinogen. 



As the above series of experiments have demonstrated the great lability of 

 caseinogen, which, under the influence of water, is readily converted into one 

 or more " metacaseinogens," experiments were next directed to ascertain 

 whether the natural caseinogen undergoes change during the course of its 

 preparation by Hammarsten's method (or modifications of the same). 



Efforts were directed towards obtaining a product which should remain for 

 as short a time as possible in contact with the various reagents employed. 



To accomplish this end a caseinogen was prepared in the following 

 manner : — Four litres of skimmed milk were diluted with 16 litres of water, 

 and to this mixture 20 c.c. of glacial acetic acid dissolved in 400 c.c. of 

 water were added with brisk agitation. After not more than two or three 



