16 



2. Peptic Digestion, a. A small quantity of osseoalbumoid 

 was treated with i liter of 0.2 per cent. HC1 containing o.i per 

 cent, of pepsin (P. D. & Co. i : 2000) in an incubator at 40 C. 

 Portions of the digestive fluid were withdrawn at intervals 

 and heated gradually to boiling. Digestion was started at 

 2.30 P.M. The following notes were recorded in connection, 

 especially, with the treatment of filtered portions of the diges- 

 tive fluid: 



3 . oo P.M. No precipitate on heat ng. 



3-30 



4.00 



4.20 



4-30 



4-45 



5.00 



5-20 



5-30 



Material gradually disap- 

 pearing. Pepsin added, 

 0.25 gram. 



Some undigested material 



still present. 

 Small amount of material 



undigested. 

 i 

 The undigested material was filtered off and the boiling 



filtrate nearly saturated with (NH 4 ) 2 SO 4 . Proteoses were 

 separated as a dark scum on the surface of the solution. The 

 precipitate dissolved readily in warm water. This solution 

 was not precipitated by heat, even after dilution. The solu- 

 tion was speedily evaporated to dryness at 40 C. and in the 

 dry state looked like scale gelatin. 



The incompletely saturated filtrate from the proteoses was 

 treated with sufficient (NH 4 ) 2 SO 4 to effect complete saturation 

 and a small amount of a dark sticky material was precipitated, 

 which dissolved readily in warm water but gave no turbidity 

 on heating. 



a'. In the preparation of osseoalbumoid the last portions of 

 admixed collagen are difficult to remove. In the peptic di- 

 gestion of osseoalbumoid admixed with collagen, the latter is 

 gelatinized and then converted into gelatoses and gelatin 

 peptones. It was thought that possibly such gelatin or its 

 hydration products might have been admixed with the os- 

 seoalbumoses obtained in the preceding experiments and that, 

 by its presence, might have prevented the occurrence of the 

 elastose-like reaction on heating. Consequently a portion 



