on the Proteolytic Action of Pepsin-hydrochloric Acid. 101 
Pfeiffer* has also called attention to the retarding action of this 
substance. 
Potassium chloride. 
With this salt our results are as follows: 
Undigested Fibrin Relative proteo- 
KCl. residue. digested. lytic action. 
0 0°1552 gram. 84-48 per cent. 100-0 
0:005 per cent. O-1817 81°83 96°8 
0°025 0°1550 84°50 100-0 
0°050 0°2565 74°35 88:0 
0-100 0°2097 79°03 93°5 
0 0°1930 80-70 100-0 
0°3 0°3997 60°02 74:3 
15 0°6815 31°85 39°4 
3°0 0:°7282 27°18 33°6 
The only noticeable difference between the action of this salt and 
the preceding, is the absence of any acceleration on the part of the 
potassium chloride and with larger percentages, a less vigorous retard- 
ing action. 
Ammonium chloride. 
For the sake of comparison a few experiments were tried with this 
salt, with the following results : 
Undigested Fibrin Relative proteo- 
(NH4)Cl. residue. digested. lytic action. 
0 0°1880 gram. 81:20 per cent. 100°0 
0-3 per cent. — 0°4649 53°51 65°9 
0'8 0°6615 33°85 41‘7 
3°0 0°6970 30°30 37:3 
By looking at the table of comparisons, we see there is little con- 
stant difference in the amount of retardation caused by the ammo- 
nium, potassium and sodium salts of hydrochloric acid. This result, 
however, is quite different from that obtained by Wolberg, who 
found that ammonium chloride influenced proteolytic action but very 
little, while both potassium and sodium chloride caused great retard- 
ation. his difference in result, may be due to difference in strength 
of gastric juice or to difference in length of time the mixtures were 
warmed at 40° C. ; certainly in our experiments, with pure anhydrous 
salts and 2 hours digestion, very little difference in digestive action is 
noticeable ; throughout, sodium chloride causes a little less proteolytic 
action than the corresponding potassium salt, while of the ammonium 
salt, little is to be said except that it causes equal retardation. 
* Centralbl. med, Wiss., 1885, p. 328. 
