and Casein Peptone. 101 



long-continued drying that a constant weight was reached and then 

 the odor was strongly suggestive of partial dissociation. In a pre- 

 vious article* on peptone, attention was called to the peculiar odor of 

 valerianic acid almost invariably noticed when the fibrin peptone was 

 dried at 110° C, but in that case it was found impossible to bring 

 the product to a constant w^eight. With casein peptone, the same 

 odor was noticeable on drying the product for analysis, but after a 

 few days heating at 110° C, the weight of the pi-oduct remained 

 fairly constant. 



On analysis, the casein peptone yielded the following results : 



Casein antipeptone A. 



I. 5792 gram substance gave 0*3185 gram H^O — 6'11 per cent. 

 H and 0-9951 gram CO,,=46'85 per cent. C. 



II. 0'4692 gram substance gave 0-2562 gram H„O = 6-07 per cent. 

 H and 0-8060 gram C0.^ = 46-84 per cent C. 



III. 0-4357 gram substance gave 55-5 c. c. N at 14-0° C. and 762*0 

 mm pressure = 15-27 per cent. N. 



IV. 0-6534 gram substance gave 83*0 c. c. N at 14*0° C. and 761*0 

 mm pressure^ 15*18 per cent. N. 



V. 0*9703 gram substance gave 0656 gram ash=6*76 per cent. 



VI. 0*4939 gram substance gave 0-0326 gram ash = 6*60 per cent. 



VII. 0*7032 gram substance gave by fusion with koh + knOj 

 0*0386 gram BaSO^=0-75 per cent. S. 



VIII. 0-6526 gram substance gave by fusion with koh + knGj 

 0-0337 gram BaSO^=0-71 per cent. S.f 



Percentage composition of ash-free substance. 



Average. 



C 49-94 49-93 .... .... j^9-94 



H 6-51 6-50 .--. 6-51 



N .... .... 16*35 16*26 .... ... 16-30 



S .... 0*70 0-66 0-68 



O - ^6-57 



100-00 



Somewhat to our surprise, on testing the purified and dried pep- 

 tone, we found that its aqueous solution gave a heavy wiiite precipi- 

 tate with nitric acid, soluble in excess of acid ; likewise, a heavy 

 precipitate with acetic acid, also soluble in excess ; with cupric sul- 



* Kuhne and Chittenden, Peptone. Studies, vol. ii. 



f The ash contained only a slight iinweighable trace of sulphate. 



