and Casein Peptone. 89 



II. 0-4345 gram substance gave 0-2734 gram H^O = 6*72 per cent. 

 H and 0-8358 gram CO„ = 50-48 per cent. C. 



III. 0-3316 gram substance gave 43-5 c. c. N at 13-7" C. and 

 756-3 mm pressures 15-70 per cent. N. 



IV. 0-3258 gram substance gave 43*1 c. c. N at 13 2° C. and 759-1 

 mm pressure= 15*86 per cent. N. 



V. 0-3306 gram substance gave 0-0126 gram ash=3-81 per cent. 



VI. 0-2262 gram substance gave 0-0085 gram ash = 3-76 per cent. 



Percentage composition of ash -free substance. 



Average. 

 C 53-17 52-43 .... .... 5^-30 



H 6-93 6-99 .... .... 6-95 



N .... .... 16-32 16-49 16-40 



This body appears to differ from a deuterocaseose obtained in 

 digestion A by nearly 1 per cent, of nitrogen, but in all other respects 

 is practically identical with it. 



As in digestion A, the precipitate first obtained by the addition of 

 acetic acid was not entirely soluble in water, a residue remained 

 soluble in dilute sodium carbonate, and which comported itself 

 exactly like the insoluble residue obtained in the preceding diges- 

 tion, apparently being a trace of casein dyspeptone. 



The original filtrate from the above acetic acid precipitate, on 

 saturation with ammonium sulphate, gave an additional precipitate, 

 hardly sufficient for analysis, but which when purified proved to be 

 identical with the corresponding body fi'om A and like it giving 

 with cupric sulphate only a very slight precipitate. 



It is thus seen that in a vigorous pepsin digestion of casein there 

 are formed, in addition to dyspeptone and heterocaseose, at least three 

 distinct caseoses all soluble and differing from each other both in 

 composition and reactions. As compared with casein, protocaseose 

 is somewhat peculiar in containing a higher percentage of carbon 

 than the mother substance. All of the other products show a very 

 much smaller content of carbon. The relative composition of the 

 products is shown in the following table : 



Trans. Conn. Acad., Vol. VI FF. 12 Nov., 18SS. 



