86 R. H. Chittenden — Caseoses, Casein Dyspe^'itone, 



III. 0-3291 gram substance gave 42-1 c. c. N at 13-9° C. and 

 756 mm pressure = 15-33 per cent. N. 



IV. 0-6835 gram substance gave 87*0 c. c. N at 14-5° C. and 

 756 mm pressure= 15*30 per cent. N. 



V. 0-5370 gram substance gave 0*0230 gram asli=4*28 per cent. 



VI. 0-3525 gram substance gave 0-0154 gram ash = 4*36 per cent. 



Percentage composition of ash-free substance. 



Average. 



C 47-57 47-87 .... 47-7^ 



H 6-75 6-70 .... 6-73 



N .... 15-99 15-96 15-97 



This substance, since it is precipitable by ammonium sulpliate, 

 cannot be considered a true peptone, yet in composition it closely 

 approaches both the ampho- and antipeptone from fibrin,* which it 

 also resembles somewhat in reactions, except in its behavior towards 

 ammonium sulphate. 



It is thus evident from the foregoing, that in this active and com- 

 paratively long continued digestion there is a much smaller amount 

 of protocaseose present than was found in our former experiments. 

 Indeed, deuterocaseose appears to predominate, while at the same 

 time the protocaseose is modified both in composition and reactions, 

 due in part without doubt, to adhering heterocaseose. Further, 

 we are inclined to consider the presence of at least two forms of deu- 

 terocaseose. We have generally considered that a proto body is never 

 completely precipitated by saturation of its aqueous solution with 

 salt, and that consequently the precipitate produced by acid in the 

 salt-saturated fluid must be a mixture of proto and deuteroproteose, and 

 this we have usually found to be the case. In the present diges- 

 tion, however, the acetic acid precipitate contained only a very small 

 amount of protocaseose, for as previously stated this precipitate when 

 purified gave only a slight turbidity on saturation of its aqueous solu- 

 tion with salt and no precipitate whatever with nitric acid ; both of 

 which reactions would indicate freedom from any large amount of pro- 

 tocaseose. This view is further substantiated by the great difference 

 in the percentage of carbon of the two bodies. To be sure we have, 

 with Nenmeister, looked on the cupric sulphate reaction as a means 

 of distinguishing between proto and deuteroalbumose, but it does 

 not necessarily follow that the same reaction will hold good for all 

 proteoses. The acetic acid precipitate does indeed give a strong 



* Kviline and Cbittenden, Studies, vol. ii, p. 40. 



