_4th Experiment._ The last galvanic experiment was made by transmitting the electric fluid from the spinal marrow to the cubital nerve near the elbow; the fingers moved quickly like those of a performer on a violin; one of the assistants who endeavoured to keep the hand shut, found that it opened in spite of his efforts. A wire was applied to a slight incision made at the end of the first finger; the hand had been previously shut; the finger was instantly extended, and, after a convulsive agitation of the arm, the dead man seemed to point his finger at the spectators, some of whom thought that he had come to life. An hour was consumed in these experiments. [116] It is shewn by the beautiful experiments of M. Legallois, that the heart derives the principle of its forces from the spinal marrow, and from the whole spinal marrow, since the destruction of one of its three portions can arrest completely the circulation. The destruction of the spinal marrow does not entirely annihilate the motions of the heart; but it weakens them sufficiently to prevent the circulation, and this weakening is so much the greater, as the portion of spinal marrow destroyed is larger. It may be presumed from this, that notwithstanding the weakening which follows the removal of a part of this marrow, the circulation may still continue if we lessen the sum of the forces which the heart must expend to maintain it. For this it is only necessary to diminish by ligatures on the arteries, the extent of the circle to which the heart distributes the blood. This conjecture is confirmed by experiment. It has been seen, for example, that the destruction of the marrow which is very suddenly fatal in full grown rabbits, ceases to be so, if before doing it the abdominal aorta is tied between the coeliac and the superior mesentric arteries. The application of the same principle to other parts of the body leads to a still more surprising result, it is this, that in order to support life in rabbits of a certain age, after having destroyed the cervical marrow, it is necessary first to cut off the head. They will be completely dead if the marrow be destroyed before they are decapitated; this arises from the fact, that by cutting off the head all this part is taken out of the domain of the circulation, and that by it the heart having need of less force to continue its function, we can weaken it by the destruction of the cervical marrow without its ceasing to perform it. [117] When an animal is thus struck, it is not certain that the concussion has not extended its effects upon a greater or less part of the spinal marrow; and it is not known consequently if the motions of the heart would not cease, even when asphyxia might be prevented by means of artificial respiration. CHAPTER XII. OF THE INFLUENCE OF THE DEATH OF THE BRAIN OVER THAT OF ALL THE ORGANS.