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. EXPERIMENT XL. In the preceding experiment I observed that the diaphragm contracted, and that the blood, which after this phænomenon I supposed to be coagulated, flowed on the contrary from the vena cava inferior, and the jugular veins, the moment the arc was applied, and appeared of a bright red colour. Is there reason to conjecture that, though great contractions cannot be produced, it is possible to excite in the interior parts of the heart some oscillations analogous to those which I observed in the muscles of the thigh and neck? This question can be determined only by new experiments. EXPERIMENT XLI. I observed in these experiments, that the more the points of contact of the arc with the biceps muscle were multiplied, the more the motion of the arm was extended; especially when care was taken to insulate the muscle by removing the integuments, and surrounding it with the wire bent in the form of a ring. Having applied arcs to the biceps muscle of each arm, I was much surprised to see the fore-arm and hand of the extremity, where the before-mentioned ring was placed, rise quickly to the height of about six inches. EXPERIMENT XLII.