92 M. H. Chittenden — Caseoses, Casein Dyspeptone^ 



Protocaseose, from WeyVs casein 2)eptone. 



I. 0-4291 gram substance gave 0-259'7 gram Iljd^%-12 percent. 

 H and 0-8140 gram CO.,=51-'70 per cent. C. 



II. 0-364'7 gram substance gave 0-2155 gram H„Or=6'56 per cent. 

 H and 0-6935 gram 00^=51-85 per cent. C. 



III. 0-4115 gram substance gave 52-5 c. c. N at 136° C. and 

 760-8 ram pressure= 15-11 per cent. N. 



IV. 0-7730 gram substance gave 96-9 c. c. N at 13-8° C. and 761-2 

 mm pressure:z= 15-10 per cent N. 



V. 0-2901 gram substance gave 0-0121 gram ash=:4-16 per cent. 



VI. 0-2959 gram substance gave 0*0120 gram ash=:4-05 per cent. 



Percentage composition of ash-free substance. 



Addition of salt-saturated acetic acid to the filtrate from proto- 

 caseose, gave a moderately heavy, gummy precipitate which, after 

 purification and removal of the acid, was completely soluble in 

 water, the solution showing no turbidity by heat, but giving a slight 

 turbidity with dilute nitric acid. It gave all of the reactions men- 

 tioned as characteristic of this precipitate. It w^as not analyzed. 



The original filtrate from the acetic acid precipitate gave on sat- 

 uration with ammonium sulphate, a small gummy precipitate which 

 after purification was found wholly soluble in water, the solution 

 giving no turbidity by heat and no precipitate with nitric or acetic 

 acid. With acetic acid and potassium ferrocyanide, however, a dis- 

 tinct turbidity was produced and with cupric sulphate a heavy pre- 

 cipitate. The substance was not analyzed. 



It is thus evident that Weyl's so-called casein peptone, however it 

 may be prepared, contains essentially the same kind of caseoses 

 found in our own digestions with pepsin-hydrochloric acid. In addi- 

 tion, a small amount of a substance was found not precipitable by 

 saturation with ammonium sulphate and Avhich gave no precipitate 

 with nitric or acetic acid, nor with acetic acid and potassium ferro- 

 cyanide, and with cupric sulphate only a slight turbidity. This 

 body, which doubtless was amphopeptone mixed with a little 

 caseose, was obtained in too small quantity for analysis. 



