Proceeding to the lower extremities, I formed an arc from the spinal marrow to the vastus internus, vastus externus, sartorius, and other muscles, and obtained strong contractions in all these muscles. Having removed the arcs and the pile, the muscles retained a small oscillatory motion, which continued for ten minutes. I observed the same phænomenon in the muscles of the neck, when I established an arc between the spinal marrow and various other parts of the trunk.
EXPERIMENT XXXVI.
Having applied the arc to the spinal marrow and the uncovered muscles of the under part of the tarsus of the right foot, the extensor muscles of all the toes, and particularly of the great toe, experienced very sensible contractions. I repeated the experiment with the arc applied, not to the spinal marrow, but to the uncovered muscles of the thigh, employed in the preceding experiment, and found the contractions excited to be much stronger. In like manner, the muscles of the soles of the feet, when I established an arc between them and the muscles of the thigh, manifested much stronger contractions than when the arc extended to any other distant part.
EXPERIMENT XXXVII.
Having examined the force of the contractions, when the arcs were applied to the surface of the muscles of the extremities, I tried what effect would be produced by introducing them into their substance. In this case, the energy of the contractions was much increased.
EXPERIMENT XXXVIII.
After trying the action of Galvanism on the extremities,
I resolved to examine the trunk. With this view, having established an arc from the spinal marrow to the muscles of the diaphragm, I obtained very sensible contractions every time the arc was applied.
EXPERIMENT XXXIX.
I then caused the thorax to be opened, that I might try the effects of Galvanism on the most important of all the muscles, the heart. The pericardium having been detached, I applied the conductor to the principal organ of life, and I even caused it to be opened, to examine whether there existed in any of its folds some fibre susceptible of oscillation; but my researches were fruitless. This insensibility ought, perhaps, to be ascribed to the want of a certain degree of heat and of animal moisture, not to be found in a body two hours after death. It will, therefore, be proper to repeat this experiment, taking care to observe all those conditions which may be necessary to ensure its success.