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



Action of Calcium Chloride on the Solution of " Nahiral " Calcium Caseinogenate.. 

 Production of Clot without Intervention of Rennet. 



To portions of 10 c.c. of a saturated solution of caseinogen in h sat. Ca(OH) 2 ,. 

 in a series of test-tubes, were added 10 c.c. of calcium chloride solutions of the 

 following concentrations: N/25, N/20, N/15, N/10, 3N/20, N/5, N/4, N/2. 

 On allowing these mixtures to stand at room temperature no change was 

 observed. On putting the tubes in an incubator, however, the solutions all 

 clotted when the concentrations of the calcium chloride added did not- exceed 

 3N/20. When the concentration was N/5, an incomplete clot formed, but 

 above this limit the liquid remained turbid, and gave no indications of a clot 

 even after prolonged warming in an incubator. The addition of rennet in 

 these cases produced, however, an aggregation even after a short interval. 

 The clots produced all shrank after standing, leaving, when clotting had been 

 complete, a clear supernatant fluid. They possessed, furthermore, a character- 

 istic physical property, which they share in common with the clot produced 

 directly by the action of rennet on milk, and which distinguishes them from 

 precipitated caseinogen, for whereas the latter, on treatment with alcohol r 

 does not alter in the general appearance, the former yield an indiarubber-like 

 mass, which, on further treatment with alcohol, is converted into hard 

 granular products, which can be pulverised only with some difficulty.* 



Clot formation can be inhibited not only by excess of the calcium salt, but 

 also by milk serum and solutions of Witte's peptone and glycine. These- 

 experiments were carried out with N/25 CaC^ in milk serum concentrated 

 to half the original bulk in vacuo, in milk serum in its original concentration, 

 in 5-per-cent. Witte's peptone solution, and in 10-per cent, glycine ; 5 c.c. of 

 these various solutions were added to 5 c.c. of the caseinogenate solution, and 

 the mixtures were allowed to stand for one hour at 37°. At the end of the- 

 period no trace of clotting had taken place. The addition of one drop of 

 rennet solution caused the clot to form in less than five minutes. The- 

 solutions containing the peptone clotted somewhat more slowly, and the clot 

 formed differed somewhat in character from the other clots, for whereas the 

 latter were firm and shrank in the characteristic manner, the former was more 

 liquid and shrank to a heavy oil. 



The behaviour of solutions of calcium and sodium caseinogenate towards 

 calcium chloride were in most respects similar, aggregation taking place 

 within only certain definite limits of concentration and being inhibited by 



* Ringer (toe. cit.), by the action of calcium chloride on a solution of calcium " caseino- 

 genate," produced a curdy deposit in the cold. This reaction differs from the one 

 described above. Ringer's "caseinogenate" solution behaves, in fact, as a " metacaseino- 

 genate " solution, the action of calcium chloride on which is described on p. 473. 



