120 Chittenden and Cummins—Influence of various Substances 
the ferment. Hydrogen was also found to be without marked action 
on the ferment, but carbonic acid retarded decidedly the proteolytic 
action of the ferment in an alkaline solution. 
We have tried the influence of three gases, such as the ferment 
would naturally be brought in contact with in the intestinal canal, 
and find that they exert a marked influence on the activity of the 
ferment. We employed, as in the preceding experiments, a neutral 
solution of trypsin, and kept the solutions saturated with the gas 
during the experiment, by passing a constant current through the 
fluid contained in a small. flask. As a control, air was passed 
through one digestive mixture, which served to keep the powdered 
fibrin in an equal state of agitation and thus make accurate com- 
parison possible. 
Following are the results : 
Undigested Fibrin Relative proteo- 
‘ residue. digested. * lytic action. 
DN ae eee a ee 0°4218 gram. 57°82 per cent. 100-0 
Hydrogent(El)ieeaessee 0°3670 63°30 109°1 
Carbonic acid (CO,) ----- 0°5665 43°35 14:9 
Hydrogen sulphide (HS). 0°4884 51°16 88°5 
From this it is seen that hydrogen gas causes a slight acceleration 
in the proteolytic action of the ferment, while carbonic acid causes 
marked retardation, which fact agrees with Podolinski’s results, and 
shows moreover, that the action of the gas is the same in neutral and 
alkaline solutions. Hydrogen sulphide also causes retardation, 
although not so marked as carbonic acid. 
Influence of alkaloid salts on the proteolytic action of trypsin. 
So far as we know, no previous experiments have been tried on this 
subject. Our results show, so far as our experiments extend, a greater 
susceptibility on the part of trypsin to the action of alkaloids than the 
amylolytic ferment of saliva. Moreover, with trypsin, the alka- 
loids in only one case cause acceleration of proteolytic action. Com- 
pared with pepsin-hydrochloric acid, however, we find that neutral 
solutions of trypsin are not so readily affected as the former ferment, 
except by one alkaloid, viz: narcotine, where retarding action is very 
pronounced. All of the alkaloids experimented with were in the 
form of pure sulphates. 
Morphine sulphate. 
This salt exerts but little retarding action. The results are as 
follows: 
ee Le Lae tree Snr en ae ee eee Oe ee ee ee a es 
siabhinitiastainriintaienameeibastemiiaaaatn daa. cee th ea 
