R. H. Chittenden — Papoid-dicjestion. 313 





Lure. 



c. 







Proleid digested. 





Temperai 



20° 



Neutral so 



36-8 per 



1. 

 cent. 



Acid sol. 



37-6 per 



cent. 



Alkaline sol. 



58 '4 per cent. 



40 





58-5 





58-6 





63-9 



45 





55-9 





57-1 





63-2 



60 





66-8 





65-7 





71-6 



70 

 Solution first j 

 boiled and then \ 

 kept at 45° C. ) 



66-3 

 9-1 





69-5 

 11-1 





68-8 

 30-4 



We notice first in these results a repetition of what has been 

 already demonstrated, viz : that in an acid solution (boracic acid), 

 papoid is slightly more active than in a neutral fluid, while in an 

 alkaline solution (sodium bicarbonate) the activity of the ferment 

 is increased very greatly. We now see that this statement holds 

 good practically for all temperatures. The most striking facts, 

 however, brought out by these experiments are : first, the marked 

 activity of the ferment at the comparatively low temperature of 

 20° C. (the temperature of the room at the time the experiment was 

 tried), especially in an alkaline fluid ; and secondly, the retention of 

 proteolytic power after the solution of the ferment has been actually 

 boiled. Here, too, the alkaline solution appears to exert a certain 

 protective influence upon the ferment, which is diflicult to explain. 

 Certainly, sodium bicarbonate alone will not dissolve a coagulated 

 proteid to any great extent, as has been already demonstrated 

 in connection with other experiments. Hence, we are forced to the 

 conclusion that in an alkaline fluid especially, papoid is extremely 

 resistant to the inhibitory effects of low and high temperatures, so 

 characteristic of most known ferments. This being true, it is ob- 

 vious that papoid in the presence of sodium bicarbonate possesses 

 special advantages in cases where it is desired to soften or digest 

 tissue or other proteid matters, at comparatively low temperatures. 

 In view of the im[)ortance of this fact, a duplicate experiment was 

 tried, in which the digestive action of papoid was again tested at 

 the room temperature (21-22° C.) on cooked beef proteids, in a 

 neutral solution, and in the presence of boracic acid and sodium 

 bicarbonate. The 10 grams of- prepared beef contained 3'7550 

 grams of dry proteid (dried at 110° C). The digestions were con- 

 tinued for 6 hours, at the given temperature. 



Reaction. Weight of undigested residue. Proteid digested. 



Neutral 2*4053 grams 35*9 per cent. 



2-0 per cent. Boracic acid 2-2394 " 40-3 



2-0 " Bicarb, soda 1-9311 •' 485 ^• 



Without papoid. 



2-0 per cent. Bicarb, soda 3-6161 " 36 " 



