1913.] 



Phenomena of" Clot " Formations. 



465 



It is necessary to call attention to two facts which are indicated in the 

 above table, viz. : — 



(1) Whereas saturated lime water dissolves only a very little more 

 than twice as much of the preparations dissolved by the half-saturated 

 solution, the latter dissolves very appreciably more than twice the amount 

 dissolved by lime water of quarter saturation. A similar result has been 

 obtained several times, and it indicates that when the strength of solution 

 is below that equivalent to half saturation, hydrolytic dissociation of the 

 calcium salt takes place. A similar phenomenon is not noticed in the case 

 of the sodium salt. 



(2) The solution capacity of sodium hydroxide for the heated preparation 

 is considerably larger than that of the equimolar solution, more especially in 

 the highest concentration. This is in accordance with the fact that caustic 

 alkalis reconvert the product obtained by heat change into its original form. 



In order to produce the changes in caseinogen discussed above water is 

 necessary. A preparation of caseinogen shows no change in its solubility in 

 calcium hydroxide after boiling for half an hour with alcohol. 



A Systematic Examination of the Action of Water on Caseinogen. 



For the purpose of a more detailed investigation on the action of water, 

 samples of caseinogen, each of 5 grm. weight, which had been " purified " 

 twice by solution in sodium hydroxide and reprecipitation with acid (but 

 without any special precautions as to temperature Or time of contact with 

 reagents) were warmed at different temperatures (in thermostat) and for 

 different periods with 10 times the weight of water. At the end of the 

 treatment the water was poured off, and the samples were then treated with 

 alcohol and ether, and air-dried. On treatment with alcohol those which 

 had been submitted to higher temperatures, and which on first heating 

 became pasty, were converted into a hard granular mass, and were finely 

 ground with alcohol in a mortar. In the following table the solubilities in 

 i sat. Ca(OH) 2 of the different preparations are given: — 



Solubility of Original Preparation, 22. 



Temperatures 



37°. 



50°. 



75°. 



100°. 



Time of heating — 













18-8 



16 -3 



14 -4 



13-0 



1 „ 



17 -5 



15 -7 



11 -o 



10 -8 





15-8 



13 -3 



10 -9 





5 „ 



13 -7 



12 -5 



10 -7 



7-4 



10 „ 



114 



11-5 



10 -8 



6-9 



26* „ 



11 6 



10-1 



6-8 



4*2 



