on Amylolytic and Proteolytic Action. 147 
Combined hydrochloric acid has a greater hindering action than 
salicylic acid, as the following results show : 
Fibrin digested 
Pancreatic solution of trypsin. in 18 hours. 
neutral 57°80 per cent. 
0-034 per cent. combined HCl+no free HCl 3°90 
O;034,5~ 4 ss HC1l+0°'C05 per cent. free HCl 2°31 
0°034 aS # HCl+ 0-010 ti Ls 0°87 
It is thus evident that in an ordinary digestive mixture, or even 
where albuminous matter is present only in limited quantity, the 
addition of hydrochloric or salicylic acid to a neutral solution of 
trypsin reduces its proteolytic action to a minimum before any free 
acid is present. 
4.— Influence of Bile, Bile Salts and Bile Acids on the Proteolytic 
Action of Trypsin. 
The addition of bile to a neutral pancreatic juice causes but little 
change in its proteolytic action, as is seen from the following results 
obtained with ox bile containing 8°3 per cent. solid matter : 
Weight of Fibrin 
Bile. undigested residue. digested, 
0 per cent. f 0°4118 gram. 59°82 per cent. 
1:0 0°3907 60°93 
10°0 0°3938 60°62 
A slightly increased action is the only effect produced on the 
trypsin.* The addition of bile to an alkaline pancreatic juice does 
not produce any very different results. The following were obtained 
with a pancreatic juice containing 0°3 per cent. sodium carbonate and 
fresh ox bile containing 10-02 per cent. solid matter: 
Weight of Fibrin 
Bile. undigested residue. digested. 
0 per cent. 0°3056 gram. 69°44 per cent. 
0°25 03074 69°26 
0°50 0°3488 65°12 
1:00 0°3633 63°67 
5°00 0°3278 67°22 
10:00 0°3603 63°97 
Here there is no increased proteolytic action, neither is there any 
very great retarding effect produced. Pure sodium glycocholate 
and taurocholate produce results similar to bile, as the following 
table shows. The pancreatic juice contained 0°3 per cent. sodium 
carbonate : 
* Compare Heidenhain, Pfliiger’s Archiv., vol. x, p. 579, 
