and Casein Peptone. 97 



Foi; separation of the caseoses the digestive fluid was neutralized 

 with dilute hydrochloric acid, giving only a slight neutralization 

 precipitate, and the neutral fluid concentrated. When moderately 

 concentrated, the solution was placed in a cool place for several 

 days to allow as much of the leucin and tyrosin to crystallize as 

 possible. The caseoses were then separated from the filtrate, in 

 the form of a gummy precipitate, by saturation of the fluid with 

 ammonium sulphate. On boiling the filtrate from the first precipi- 

 tate, and adding still more ammonium sulphate, a second gummy 

 precipitate gradually settled out of the hot saturated fluid. This 

 precipitate was separated from the fluid, the latter being saved for 

 the detection of any peptone formed, washed with hot saturated 

 ammonium sulphate solution, then dissolved in water and dialyzed 

 until all traces of sulphate were removed. In the dialysis, no signs 

 of any gummy heterocaseose or other like body was noticed. The 

 caseose was precipitated from the suitably concentrated fluid with 

 alcohol, boiled repeatedly with alcohol to free it from any adhering 

 tyrosin, and finally dried at 110° C. 



The substance was extremely soluble in water, the fluid remaining 

 perfectly clear when heated. Acetic acid produced a heavy precipi- 

 tate, soluble in excess, and in the acid fluid potassium ferrocyanide 

 gave a heavy precipitate. Dilute nitric acid, added to the aqueous 

 solution produced a white precipitate readily soluble in excess of acid, 

 and when heated showed the xanthoprotein reaction. 



Cupric sulphate also gave a heavy white precipitate. On analysis, 

 the following results were obtained : 



fi deiiterocaseose, formed by trypsin. 



I. 0"3355 gram substance gave 0*1847 gram H30 = 6*ll per cent. 

 H and 0-5990 gram C02 = 48-68 per cent. C. 



II. 0-3459 gram substance gave 0*1871 gram H„O = 6*01 per cent. 

 H and 0*6120 gram 00^ = 48*24 per cent. C. 



III. 0*5399 gram substance gave 63*0 c.c. Nat 13*8° C. and 

 762*6 mm pressure = 13*63 per cent. N. 



IV. 0*4166 gram substance gave by fusion with koh + kno, 

 0*0300 gram BaSO^=:0*98 per cent. S ; after deducting sulphur of 

 ash = 0*95 per cent. 



V. 0*5496 gram substance gave by fusion with koh + kno, 

 0*0380 gram BaSO_=0'95 per cent. S ; after deducting sulphur of ash 

 = 0*91 per cent. 



Teans. Conn. Acad., Vol. VIII. 13 Nov., 1888 



