196 
ON RUNNET AND CHYMOSINE. 
The mucous membrane of the stomach of a calf was ex- 
hausted* by macerations in alcohol and in water. The first 
was. made with 800 grs. of alcohol, of 27° c, for seven 
months. The second were continued with 8000 grs. of water, 
and did not last more than twelve hours each. After this, the 
mucous membrane was dried; it no longer reddened litmus 
paper, when pressed on the moistened inner membrane. A 
part of this dried membrane was placed in 1800 parts of un- 
skimmed milk, and the temperature raised to 50° c; at 45° c. 
the coagulation was complete. The membrane was separated, 
washed, dried, and weighed; there was no loss. This mem- 
brane was placed in a quantity of milk equal to the former, 
the milk was heated to 50° c, and, as should happen, there 
was no action. 
Boiling milk was not altered when I placed in it the ex- 
hausted mucous membrane. 
Having ascertained that the active principle of runnet was 
produced by the mucous membrane of the stomach, I examined 
whether any other portion of the digestive tube contained it, 
and whether this matter was peculiar to the mammalia. It re- 
sulted from these researches, that this matter was not con- 
tained in any other part; that it does not exist in the craw of 
the Gallinacese, but that it may be found in the mucous mem- 
brane of the gizzard of these animals, &c, that it is peculiar 
to the stomach of all animals, (I generalize by induction,) and 
that its functions are essential for digestion, inasmuch as it fa- 
vors chymification. 
Liquid runnet is slightly amber-colored, when prepared 
with the stomach of a calf and alcohol of 27° c. Its odor is like 
butter, and its reaction with test paper is acid. When satu- 
rated it becomes foul and disengages ammonia. When satu- 
rated with ammonia and filtered, there is obtained a transparent 
liquor with the odor of runnet, but which has no action on 
milk, for six coffee-spoonfuls had no effect on 125 grs. of milk. 
If the filtered liquor be set aside in a corked flask, it deposits 
*This experiment differs somewhat from that of M. Berzelius. 
