EXPERIMENT XXVII.
Being desirous to examine, according to the principles of Galvani, the power of an arc of animal moisture in warm-blooded animals, I recollected that I had several times observed simultaneous convulsions produced by these means in two frogs, and recently in the heads of two oxen, the arc being conveyed from the one to the other in different ways.
I placed the two heads in a straight line on a table, in such a manner that the sections of the neck were brought into communication merely by the animal fluids. When thus arranged, I formed an arc from the pile to the right ear of one head, and to the left ear of the other, and saw with astonishment the two heads make horrid grimaces; so that the spectators, who had no suspicion of such a result, were actually frightened. It was however observed, that the convulsions excited in the heads disposed in this manner, were not so strong as those produced when I performed the experiment on each head separately. It is certain that, in this experiment, the arc of animal moisture supplies the place of a continuation of the nervous and muscular fibres.
EXPERIMENT XXVIII.
Having tried the effect of Galvanism on the exterior part of the head, I proceeded to examine the phænomena exhibited by the interior organs when treated in the same manner. I therefore removed the upper part of the cranium by a section parallel to its base, uncovered the pia mater, and established an arc from one of the ears to the medullary substance. On the application of the arc strong convulsions were observed in the face. While preparing the brain for my experiments, I remarked that, in dividing the muscles of the forehead, at each stroke of the dissecting knife, very strong contractions, which continued after the dissection
was finished, were excited in the muscles of the face. I was informed that this is an uncommon phænomenon in anatomical dissections; and therefore I shall leave it to anatomists to determine whether it was occasioned, either in whole or in part, by the preceding action of the pile.
EXPERIMENT XXIX.
Having then separated the lobes of the brain, I applied the arc to the corpus callosum, to the ears or to the lips, and found that the whole osseous box and the muscles of the face were violently agitated. Some of the spectators even imagined that the corpus callosum itself was affected by a peculiar convulsion; but it is possible that this emotion was owing to a mechanical impulse which shook the whole head. New experiments will, therefore, be necessary before any thing further can be said in regard to this observation.
EXPERIMENT XXX.
Having carried the dissection to the olfactory nerves, and even to the crossing of the optic nerves, I formed an arc from these parts to the lips and the eyes, and obtained contractions, but very weak in comparison of the preceding. I observed that on touching the optic nerves with one of the arcs no sensible convulsions were produced in the eye-lids.