250 MR. H. F. BAXTER’S EXPERIMENTAL INQUIRY AS TO THE EXISTENCE 
and 8 to the same cause ? Let us take the simple fact, that, when the mucous mem- 
brane of the small intestine and the blood flowing from it are formed into a circuit, 
a deviation of the needle amounting to 3°, 4° or 5° is obtained, the intestine being 
empty and therefore uninfluenced by the circumstances we have just now mentioned ; 
why did the effect not occur in experiment 11 ? the conditions appeared to be pre- 
cisely similar; or in experiments 7 and 10, when the artery was wounded ; or in expe- 
riments 3 and 4, when blood flowing from a different part formed the circuit; or in 
experiments 3, 5, 9, when a circuit was formed between the inside and outside of the 
gut? Did not the failure arise in these instances in consequence of the absence of 
one necessary condition, the flowing of the blood from the same part, the transmis- 
sion of the carrying particles from one electrode to the other, as shown in experi- 
ments 2, 3, 4, 5 and 7 ? 
Without entering into any discussion as to the mode in which the effect may be 
supposed to be brought about in the living animal, and the difference observed when 
the stomach and other parts were formed into circuits in rabbits, and when the same 
circuits were formed in cats, we may be justified in adding the following to our 
former inference, viz. that the effect is produced during the organic action of the part, 
it ceasing after the death of the animal. 
Instead of endeavouring to refute the notion that the stomach and liver form poles 
similar to those of a galvanic circle, let us briefly allude to the experiment and con- 
jecture of Wollaston. Was not that experiment to illustrate, rather than to prove 
his conjecture ? and are not these experiments identical with that conjecture? He 
evidently saw, mentally speaking, the meaning of tliat phrase “ an axis of power,” &c. 
This inquiry has been undertaken with the advantage both of Faraday’s labours and 
the use of the galvanometer. Wollaston’s conjecture and experiment have existed 
for forty years. 
The following is a brief recapitulation of the general conclusions which may be 
deduced from the foregoing experiments and reasonings; — 
1. When the electrodes of a galvanometer are brought into communication, one 
with the mucous membrane of the alimentary canal, the other with the blood flowing 
from the same part, a deviation of the needle takes place, indicating that the secreted 
product and the blood are in opposite electric states. 
2. That the effect occurs during the life of the animal, it ceasing after its death. 
3. That the effect may be considered as arising from the decomposition of the 
blood ; i. e. the changes which occur during the formation of the secreted product 
and venous blood. 
4. That these changes are effected by the organic action of the part. 
The author begs to acknowledge the great kindness that he has received from Sir 
B. C. Brodie, Bart., and from Dr. Todd. 
] 2 New Burlington Street, 
