on the Proteolytic Action of Pepsin-hydrochloric Acid. 95 
bacteria; although doubtless, the action of any one percentage is de- 
pendent in part, upon the amount of organic matter present. Marcus 
and Pinet* found that the permanganate in 0-1 per cent. would pre- 
vent the development of bacteria and in 1°5 per cent. would kill 
the fully developed organisms. 
Potassium dichromate. 
A single experiment with this salt gave the following results; 
showing a decided retarding action on gastric digestion. - 
Undigested Fibrin Relative proteo- 
KeCr207. residue. digested. lytic action. 
0 0°2028 gram. 79°72 per cent. 100-0 
0-01 per cent. 0°2476 75°24 94-4 
0-10 0°6383 36°17 45°3 
Potassium cyanide. 
Potassium cyanide we found very active in diminishing the diges- 
tive power of pepsin; due in great part doubtless, to decomposition 
of the cyanide by the hydrochloric acid of the gastric juice with 
conseqent formation of pepsin-hydrocyanic acid. Our first results 
were as follows: 
Undigested Fibrin Relative proteo- 
KCN. residue. digested. lytic action. 
0 0°3255 gram. 67°45 per cent. 100°0 
0°25 per cent. 09687 3:13 4°6 
0°50 079912 0°88 163} 
Here, the fibrin did not swell at all, indicating the probable ab- 
sence of free hydrochloric acid, although of course the potassium 
cyanide might, per se, prevent swelling. 
With very much smaller percentages of cyanide, we obtained the 
following results: 
KCN. “residue. digested. Maytie action. 
0 0°3098 gram. 69°02 per cent. 100°0 
0°'005 per cent. 04376 56°24 81°5 
0°025 0°3750 62°50 90°5 
Potassium ferrocyanide. 
With this salt, the results are practically the same as with potas- 
sium cyanide; almost complete stopping of proteolytic action, even 
in the presence of small fractions of one per cent. 
* Action de quelques substances sur les bactéries de la putréfaction, Compt. rend. 
Soc. de Biolog., 1882, p.718. Abstract in Jahresbericht fiir Thierchemie, 1882, p. 515. 
