By forming an arc from the feet to the spinal marrow, first applying armatures, and then employing a solution of muriate of soda as in the preceding experiments, I obtained contractions, but weaker than those in the upper extremities. As there was reason to suspect that this diminution arose in part from the position of the trunk, I placed the body in such a manner, that, while the thighs rested on the edge of the table, the legs, which hung over it, were at full liberty to move. This difference in position produced a difference in the results; and I intend to repeat the experiment, according to this arrangement, applying the arc directly to the crural nerves.
EXPERIMENT LI.
A small portion of the great pectoral muscle being detached
from the ribs, and exposed to the action of the pile, exhibited strong contractions, and the motion of the diaphragm was also very remarkable. The heart alone, though carefully subjected to all the operations detailed in the 47th experiment, remained perfectly motionless.
EXPERIMENT LII.
Having brought the separated head near to the neck of the trunk, I established a communication between it and the trunk by means of the animal moisture alone; and an arc being then formed from the head to different parts of the trunk, sensible contractions were produced, and particularly in the latter. This observation seems still further to prove that an arc of moisture has power to excite muscular contractions. In this, as well as in the preceding experiments, if any of the spectators, while an arc was established by means of the pile, brought a frog prepared in the usual manner near to the human body, the frog experienced strong contractions, though at a distance from the place to which the action of the Galvanism was determined.
EXPERIMENT LIII.
After three hours had been employed in these experiments, I conceived the idea of trying the action of Galvanism on some parts of the body separated from the trunk.
One of the legs, therefore, was amputated six inches above the joint of the knee; and an arc being established from a point in the plane of the section to the knee, I obtained contractions similar to those which had been produced before the limb was separated from the body. I then formed an arc of moisture, by applying the amputated limb to the trunk; and having determined the action of the pile to the spinal marrow and the foot, I obtained very sensible contractions. I observed, on this occasion, that a frog, prepared some time before, and which was accidentally lying on the table, at each application of the metallic arcs moved like an electrometer, and thus confirmed the action of an arc of moisture.
EXPERIMENT LIV.