4G4 



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



in the behaviour of the various samples. The action of water at higher 

 temperatures was first investigated. 



A sample of caseinogen, freshly precipitated, was treated with alcohol and 

 ether, and then air dried. (Solubility, 21*5.) It was then warmed with 

 water for half an hour at 70°, which caused it to form at first a pasty mass, 

 which became more granular as the heating was continued. It was then 

 treated with alcohol and ether and air-dried. The solubility in \ sat. 

 Ca(OH) 2 was now 10*9, or only a little more than half that of the original 

 preparation. On redissolving the heated product in sodium hydroxide and 

 reprecipitating, a preparation was obtained with the solubility 25*3. Another 

 sample of the heated product was " purified " by solution in ammonia, and 

 the preparation thus produced had a solubility of 22 - 3. A third sample was 

 " purified " by dissolving in calcium hydroxide. The caseinogen was only 

 very partially precipitated by acetic acid from this solution, and the filtration 

 of the precipitate through paper could only be effected with difficulty. The 

 solubility of this preparation was 12 - 6. 



It is therefore obvious from these experiments that caseinogen, on treat- 

 ment with hot water, is converted into a product which is considerably less 

 soluble than the original substance in lime water, but which, on " purifica- 

 tion " by solution in caustic alkalis and reprecipitation by acids, is recon- 

 verted into the substance from which it was formed. 



The solubility of heated and unheated preparations in various strengths of 

 alkaline solutions was next determined, and a comparison of the solution 

 capacities of calcium and sodium hydroxide was made. 



Saturated Ca(OH) 2 solution requires for neutralisation 4 - 3 c.c. N/10 acid. 



4*3 



An equirnolar Na(OH) solution requires for neutralisation — c.c. N/10 acid. 



In the following table the figures indicate the number of cubic centimetres 

 of N/10 acid necessary to neutralise the ammonia produced by the 

 Kjeldahlisation of 5 c.c. of the solution. (For method of determining 

 the solubilities and sources of error, see pp. 462-3.) 



Original preparation. 



Heated preparation. 



Solubility in 

 Ca(OH) 2 

 solutions. 



Solubility in NaOH 

 solutions equimolar 

 with 



Solubility in 

 Ca(OH) ; 

 solutions. 



Solubility in NaOH 

 solutions equimolar 

 with 



Saturated, 46 '5 

 \ saturated, 22 "8 

 i saturated, 6 - 6 



Saturated Ca(OH) 2 , 41 -4 

 § saturated Ca(OH) 2 , 20 '3 

 i saturated Ca(OH) 2 , 10 -0 



| 



Saturated, 23 '9 Saturated Ca(OH). ; , 36 "6 

 4 saturated, 11 '9 | \ saturated Ca(OH) 2 , 16 -4 

 i saturated, 4 - 3 j £ saturated Ca(OH) 2 , 7 "6 



