15 



It was necessary to determine whether any osseoalbumoses 

 that might thus be produced would behave like elastoses when 

 their aqueous solutions are heated. In all of these experiments 

 the osseoalbumoid employed was made by the Hawk and Gies 

 method. 1 



A. ON THE PREPARATION OF DIGESTIVE PRODUCTS OF OS- 

 SEOALBUMOID. J. Tryptic Digestion, a. A small quantity 

 of osseoalbumoid, which had been made in a preliminary way, 2 

 was subjected to the action of a strong, alkaline tryptic solution 

 for 24 hours at 40 C. The true osseoalbumoid in the prepara- 

 tion was completely digested ,by that time. Proteoses were 

 formed. A small amount of admixed collagen remained un- 

 digested. The whole of this collaginous residue was readily 

 converted into gelatin. 



b. After 5 hours' digestion of fresh osseoalbumoid 3 in 80 cc. 

 of 0.25 per cent. N^COg, containing 0.5 gram of trypsin 

 (Merck), the mixture was filtered and the filtrate saturated 

 with (NH 4 ) 2 SO 4 at the boiling temperature. During the 

 digestive process samples of the solution were withdrawn 

 at intervals of 45 minutes and when examined gave negative 

 results in the heat-precipitation test. 



The (NH 4 ) 2 SO 4 ppt. was dissolved in water, dialyzed until 

 free from sulphate and evaporated to dryness at 40 C. on a 

 water bath. The residue after 5 hours' digestion was sub- 

 jected to the action of a fresh trypsin solution and allowed 

 to digest for 18 hours longer, then treated by the process de- 

 scribed above. 



c. A sample of the original ossein shavings was subjected 

 to the influence of a very active tryptic solution but the shav- 

 ings were unaffected. The filtrate from the unchanged bone 

 shavings was tested with fibrin as to its digestive power and 

 found to be active. A repetition of this experiment yielded 

 the same negative result. 



1 Hawk and Gies: American Journal of Physiology, 1902, vii, p. 340; 

 also, Gies and collaborators: Biochemical Researches, 1903, i, p. 181 (Re- 

 print No. 6). 



2 From ossein shavings prepared in 1900 and kept dry meanwhile. 



3 Made from a portion of the same ossein shavings (a). 



