—_”* 
Uranium Salts on Ferment Action. 269 
acetate and the reason doubtless lies in the fact that the acid in these 
two salts is wholly incapable of forming an active compound with 
pepsin, and thus when a percentage of the salt is added sufficient to 
use up all of the hydrochloric acid of the gastric juice, digestive 
action comes to a full stop. 
Potassio uranie oxychloride. 
U0.Cl. + 2KCl Relative 
+2H.0. Undigested residue. Fibrin digested. proteolytic action. 
0 0:3063 gram. 69°57 per cent. 100-0 
0°025 per cent. 0:2472 75°28 108-0 
0-050 0°2128 13°17 113°5 
0-100 02582 74°68 107°6 
0-300 02648 73°d2 105°9 
0-500 0:°3578 64°22 92:5 
With this salt, unlike any of the preceding, there is to be seen a 
direct stimulating action on the ferment. Only in the presence of 0°5 
per cent. of the salt is there any retarding effect produced. This 
naturally suggests that possibly uranium per se, at least in small 
fractions of a per cent., has really a stimulating effect on ferment 
action, but that owing to its combination with acids, in the forma- 
tion of salts, its apparent effects in the case of pepsin-hydrochloric 
acid are those due to combination of the normal acid of the gas- 
tric juice and liberation of the acid of the uranium salt. In this 
way only, can we explain the noticeable difference in action of 
the oxychloride and the other uranium salts. Thus 0°5 per cent. of 
the former causes but slight diminution in proteolytic action, while 
with all the other salts, the same percentage causes on an average, a 
diminution in proteolytic action of at least 50 per cent. This would 
apply, of course, only to small percentages of uranium, for larger 
amounts of oxychloride would cause the formation of an indigestible 
uranium-albumin compound. 
Here, however, as in the case of all the salts, the action of any 
given percentage is constant only under definite conditions. Dimin- 
ish the amount of ferment, for example, and the amount of dissolved 
proteid matter consequent thereto, and then the retarding action of 
the same percentage of uranium salt will be correspondingly in- 
creased. 
This is well illustrated in the following series of experiments with 
potassio uranic oxychloride. Using the same percentages of salt as 
employed in the preceding series, with the same strength of acid, 
but with onlv half the same content of pepsin extract, and the fol- 
lowing results were obtained ; 
