21 



isolated from the hashed ossein shavings as in experiments 

 d-d. 



A portion of the product was subjected to peptic digestion 

 as in the previous experiments (a-d), and after four hours' 

 digestion, the mixture was filtered and the filtrate neutralized 

 with NaOH. The precipitated phosphates were removed 

 by filtration and the remaining solution saturated with 

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



The precipitate obtained by the saturation process was 

 dissolved in water, dialyzed free from sulphate and speedily 

 evaporated to dryness at 40 C. over a water bath. This 

 product when dissolved in water did not give the heat pre- 

 cipitation test. The residue which remained undigested after 

 four hours was again subjected to digestion for 18 hours longe'r, 

 and the fluid then treated by the process described above. 



j. Summary of Results of Procedures A (1-2). a. Osseoalbu- 

 moid prepared from ossein shavings made in 1900 and kept 

 dry, meanwhile, yielded osseoalbumoses on tryptic digestion. 



b. Ossein shavings themselves were not appreciably affected 

 by tryptic digestion. 



c. Osseoalbumoid made from old desiccated ossein shav- 

 ings, when subjected to peptic digestion for 1/2 hour, yielded 

 a product which gave a sharp heat-precipitation test; that is, 

 a precipitate came down on heating some of the filtered di- 

 gestive mixture, which precipitate dissolved on further heat- 

 ing and reappeared on cooling. An aqueous solution of the 

 precipitate produced by (NH 4 ) 2 SO 4 -saturation of this 

 digestive mixture, gave the same heat-precipitation result. 

 This result could be obtained only when the reaction of the 

 heated solution was acid. 



d. The pepsin used in the digestion was not responsible 

 for this reaction. 



e. After subjecting osseoalbumoid (the same product as the 

 above) to peptic digestion for i, i> and 3 hours, respectively, 

 in no case did the filtered digestive mixture, nor a solution 

 of the (NH 4 ) 2 SO 4 -saturation precipitate from the digestive 

 mixture, give a heat-precipitation test. 



/. Osseoalbumoid isolated from fresh ossein shavings, after 



