OF CURRENT FORCE DURING SECRETION. 
245 
The stomach was laid open, one of the plates pressed on the mucous membrane, the 
other upon the surface of the liver; a decided effect was now produced upon the 
needle, and by making and breaking contact so as to catcli the vibrations of the 
needle, made to increase to 15° or 20°, The points were used as before ; no effect. 
When the surface of the plate of one electrode was connected with the mucous mem- 
brane of the stomach, and the point of the other electrode with the liver, the effect 
upon the needle was greater than when the pointed extremity of the electrode was 
connected with the stomach, and the surface of the plate with the surface of the liver; 
in the latter instance the effect was very slight ; but in neither instance was the effect 
so great as when both plates were used. The direction of the current, as indicated 
by the needle, was from the stomach along the metallic conductor to the liver. 
The liver was removed and placed upon the intestines, the stomach remaining ; the 
same actions occurred, but not to the same extent. 
Stomach almost empty. 
Considering that the failure in former experiments arose from the want of surface 
at the free extremities of the electrodes, the sealing-wax was removed. 
Exj)eriment 2. — Rabbit. The pointed extremity of one electrode was inserted into 
the caput coli, and pressed against the mucous membrane, the inferior mesenteric 
vein was wounded, and the plate of the other electrode dipped into the blood ; the 
latter positive 5°, and made to increase by making and breaking contact. 
An incision was made into the stomach, and the plate of one electrode inserted into 
it ; the plate of the other lightly pressed on the surface of the liver; stomach positive 
10°, and made to increase by making and breaking contact. 
In cleaning one of the electrodes it broke, about half an inch from the plate. The 
plate of the electrode was in contact with the mucous membrane of the ilium, and 
the pointed extremity of the broken electrode inserted into a vein coming from the 
same part ; blood slightly positive, 
A platinum wire (No. 18), six inches in length, was flattened out at one extremity 
so as to present a surface three-fourths of an inch in length, and one-sixth of an inch 
in breadth. This will be called electrode A (E A). The former electrode with the 
plate attached, electrode B (E B). The broken electrode, having the broken extre- 
mity flattened out to the extent of one-fourth of an inch in length and to one-eighth 
of an inch in breadth, electrode C (E C). 
In describing the circuits, when the pointed extremity is in contact with the animal, 
it will be stated the p of E A, &c., otherwise the broad extremity is used. 
Experiment 3. — Rabbit. Mucous membrane of the ilium and vein from the same 
part ; the jo of E A in contact with the former to the extent of an inch and a half, 
the of E B with the latter; blood positive 4°; when E B was used a greater 
effect, and made to increase; no effect ensued when the of E B was inserted into 
a different vein ; returning to the former vein, the action upon the needle occurred ; 
should the blood however from the two veins become mixed, then an effect upon the 
needle ensued, more especially if E B be used. No effect when E B was placed 
2 K 2 
