Page:Popular Science Monthly Volume 2.djvu/709

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bonic acid are then at their maximum; the blood of the veins is extremely dark—the muscle is growing and acting both at once.

These are modifications which the muscular fibre undergoes during life. When death occurs and the blood is no longer renewed, muscular irritability disappears after a time which varies, and in an order which is fixed. The left ventricle of the heart first ceases to be excitable, then the intestine, the bladder, the iris, the muscles of animal life; the right auricle of the heart dies last; it is the ultimum moriens. The organic matter making up what is called the flesh decomposes, and is thenceforth governed entirely by chemical forces. The juices it contains become acid, coagulations take place, and then comes on the condition called by the name of corpse-like rigidity. Thus changed, the muscle is no longer excitable; but, if it is subjected at this instant to a current of arterial blood, it immediately revives, rigidity disappears, the muscle-fluids regain their former composition, and the individual activity of the fibre displays itself anew. Experiments establishing this great fact have been tried, not only on animals, but also on man even, and under circumstances that present some difficulty in the recital; the dramatic side of the subject is vivid enough to allow of a strictly scientific narration by itself. We will relate the transfusions performed by Brown-Séquard on two persons beheaded at Paris in June and July, 1851.

The first experiment was tried on a man aged twenty. He was beheaded at eight o'clock in the morning; eleven hours later all trace of irritability had disappeared from most of the muscles of the body. Injection into the muscles was begun at ten minutes past nine in the evening; the quantity of blood (which the operator took from his own veins) was enough for a limited part of the body; he therefore confined his experiment to the hand. Injection was made by the artery in which the pulse is usually sought, a little above the wrist, and, of course, in the direction of the fingers; it was urged at first quite fast, then slowly. The blood which went in bright colored, passed out dark from the vein, as is the case in life. The operation continued thirty-five minutes, and, ten minutes after that time, irritability had returned; a movement in the muscles of the hand could be artificially excited.

With the second subject, injection of the blood of a healthy dog was made; the blood had been first deprived of its coagulable matter, and beaten up in the air; there was about a pound of it. The subject was a strong man, forty years old. Death had occurred at eight o'clock in the morning; at twenty-five minutes past ten in the evening rigidity was complete, without a trace of contractility under the influence of stimulus. The arm was amputated, and at twenty minutes past eleven Brown-Séquard effected injection by the brachial artery. The skin at first took a livid color, but very soon the roots of the hair grew erect, giving the effect of goose-flesh, as it is called. This arti-