302 



R. H. Chittenden — Pa2)oid-digestion. 



From these results, it is plain that papoid will digest coagulated 

 egg-albumin in neutral, acid and alkaline solutions ; its solvent 

 power being most marked, in this case, in the presence of 2 to 4 

 per cent, sodium bicarbonate. 



In considering these quantitative results, and those which follow, 

 it must be noted that the figures given cannot be taken as an exact 

 measure of the extent of digestion, but simply as a measure of the 

 conversion of the insoluble proteid into soluble products. Thus, it 

 may be that the so-called undigested residue consists in some cases, 

 wholly or in part, of alteration products, which though insoluble 

 are still products of the activity of the ferment, while in other 

 cases the residue ma}^ consist simply of the unaltered proteid. Dis- 

 cussion of this point, which has a bearing on the completeness of 

 papoid digestion, must be reserved until we come to consider the 

 products of digestion. 



h. Action on Coolx:ed Beef JProteids. 



The beef proteids used in this series of experiments were ^^I'epared 

 by taking lean, round steak, passing it through a hashing machine, 

 then washing it repeatedly with water until all blood was removed 

 and it had become nearly white in color. It was then placed in fresh 

 water and heated until the water boiled, after which it was strained 

 ojff through a cloth filter and pressed as dry as possible. 



Each digestive mixture contained O'o gram papoid, 10 grams of 

 the cooked beef, and 25 c. c. of water in which were dissolved the 

 indicated percentages of acid and alkali. 



The 10 grams of cooked beef contained 3*7438 grams of dry pro- 

 teid (dried at 110° C.) 



The digestions were all warmed at 45° C. for 5^ hours, with fre- 

 quent stirring, after which the undigested residues were filtered off, 

 washed, dried and weighed as described in the preceding experi- 

 ment. 



Reaction. 



Neutral 



0*05 per cent. Hydrochloric acid 



Welfflit of 

 undigested residue. 



1*7782 grams. 



1-7221 



Cooked beef 

 proteids digested. 



52-5 per cent. 

 54-0 



0*1 





t < (( 



1-9179 



.'( 



48-7 



>( 



0-2 





(( 11 



3 0679 



(( 



18-0 



i i 



2*0 





Bicarb, soda 



1-4338 



( ( 



61*7 



a 



4*0 





a a 



1-2651 



< ( 



66-2 



i i 



0*2 





Without papoid. 



Hydrochloric acid 



3-5738 



(( 



4-5 



i i 



4*0 





Bicarb, soda 



3-5205 



( ( 



5-9 



a 



