OF CURRENT FORCE DURING SECRETION. 
247 
Experiment 6. — E B covered with some blood from the cat, was dipped with E A 
into water. A similar circuit was formed with fresh blood and water containing 
faecal matter from the colon, the electrodes were close to each other. A portion of 
the colon of the cat, with its contents, was removed and placed in a weak solution 
of potash ; E A and E B were dipped, one into the solution, the other into the gut, 
and then changed ; in no instance did any effect occur. Some very dilute nitric 
acid was mixed with the contents of the colon and the same circuit formed ; con- 
tents of the colon positive 3°. Can the difference, which is observed between cats 
and rabbits, as to the direction of the current when the stomach and liver are formed 
into a circuit, be attributed to the action of the poison, although no poison had been 
taken into the stomach ? 
Experiments 7 and 8 were upon rabbits ; in one, prussic acid was used as in ex- 
periment 5 ; in the other, after a circuit had been formed between the mucous mem- 
brane of the stomach and blood flowing from the aorta, an opening was made and 
about ten drops of prussic acid poured into the stomach. The results only need be 
detailed. The mucous membrane of the stomach was positive to the following parts : 
surface of liver, mesentery, blood flowing from the vena porta and aorta, gall-bladder, 
mucous membrane of the duodenum and of the caput coli. 
The blood flowing from the mucous membrane of the ilium and of the caput coli 
was positive to these parts from 3° to 5°. 
The surface of the liver and the mesentery were slightly positive, when E B was 
in contact with them, to the mucous membrane of the ilium and caput coli. 
In the following cycuits no result was obtained: — Mucous membrane of the 
stomach and vena porta, the pointed extremity being inserted into the latter. Gall- 
bladder and vena porta. Mucous membrane of the ilium and that of the caput coli. 
Mucous membrane of the ilium and vein coming from the same part; this occurred 
when the aorta had been wounded, no blood flowed and the intestine was pale. 
The contents of the stomach were positive to those of the colon when formed into 
a circuit out of the body ; the effect was not so great as when the circuit was formed 
between the stomach and caput coli, the parts remaining in situ. In one experiment, 
the stomach, liver and intestines were removed from the body : the stomach was 
positive to every other part; it was detached, emptied of its contents, and washed, 
the same circuits then formed, but no effect ; some of the food replaced, the former 
effects were reproduced, but not so decided. The caput coli was slightly negative 
to the liver and mesentery. With the small intestines no effect. In both experi- 
ments the contents of the stomach reddened litmus paper, and formed a coarse, dry, 
compact mass ; those of the caput coli a soft homogeneous mass, but produced no 
effect either on litmus or turmeric paper. From these two experiments, the differ- 
ence of effect between cats and rabbits, when the stomach and liver are formed into 
circuits, cannot be attributed to the action of the poison. 
At the present stage of the inquiry we may be justified in drawing the following 
