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the action of the two agents could not have been distinguished by a stranger ignorant of the cause of the symptoms. The chest was fixed; and death took place in four minutes. An hour after death, the body was opened. The right side of the heart and the whole venous system were charged to distension with dark blood, which was perfectly fluid, and remained so for three hours on exposure to the air. In the left side also there was blood, of a bright red colour, and fluid. Set aside, this arterial blood coagulated in fifteen minutes, on exposure to the air at a temperature of 70°. The corpuscles were very much modified. In this experiment, the first of the series on a living animal, the ammonia was added in a poisonous dose, and the results were strikingly marked.

The analogy between the actions of ammonia and strychnia is so striking when the former is thus thrown in excess into the circulation, that I cannot dwell too strongly on the fact, since it may have an ultimate bearing on the mode in which strychnia destroys life, and the means to be adopted in cases where this alkaloid is fatally administered. In an experiment in which Dr. Halford lent me his assistance, the same results were observed, under the same circumstances.

EXPERIMENT CCCCIX. Transfusion of Blood. I laid bare the jugular vein of a healthy terrier dog, and drew off two ounces of blood into an evaporating dish containing three minims of liquor ammoniæ (specific gravity .880) with thirty minims of water. Other two ounces of blood were drawn off into another dish containing no ammonia, and set aside to coagulate. The vein meantime was tied above the opening. After four minutes, the blood in the second cup had firmly coagu

lated. The ammoniated blood was still completely fluid. After five minutes more had elapsed, the nozzle of the injecting syringe was introduced into the vein of the animal, and the ammoniated blood was injected. Dr. Halford, who managed the syringe, took great care to introduce the fluid slowly, and a full quarter of an hour was taken up in this way. Then the syringe was withdrawn, and the vein was tied beneath the opening.

In the course of this operation, not a dangerous symptom supervened. The blood ran easily. As it first reached the heart, that organ, which had been flagging, beat with a little more force, and sustained this activity, without abnormal increase. The animal recovered without the slightest indication of injury, and it is alive and well now.

A small portion of the ammoniated blood left in the evaporating dish, was observed to coagulate thirty-five minutes after the blood was first drawn; it formed into a firm clot. The temperature of the day was 75° Fahr.

In performing the operation of transfusion by this simple means, in the human subject, in the extreme cases adapted to the operation, a few precautions are required. The amount of ammonia first added to the blood about to be transfused, should not exceed two minims of the stronger liquor ammonia to the ounce of blood; for it is quite easy, if a diluted solution of the ammonia be ready at hand, to add a little more in course of the operation, if the blood should show a tendency to coagulate. The ammonia diluted with water, in the proportion of one part of the alkali to ten of water, should be placed in the vessel in which the blood is caught from the vein; and the blood as it falls into the vessel should at first be very gently stirred. When

sufficient blood is obtained, and the injecting syringe is at work, the injection should be made with the greatest care and slowness. Indeed, scarcely any pressure on the piston is required, and there is no cause for haste. This is a great advantage; for, I take it, one of the dangers of transfusion is the rapid distension of an empty and enfeebled heart with a full charge of blood. Harvey, whose shrewdness seems to have let nothing in his way escape observation, refers to the syncope which sometimes occurs in bleeding, not as a result of the hæmorrhage, but on the removal of the fillet; or, as the vulgar say, "from the turning of the blood." Harvey thought that this occurred from the coldness of the blood which retreated on the heart; but I think that I have demonstrated by experiment, in another place, that the effect is due to the sudden load of blood thrown upon the enfeebled organ.

*

With these precautions the operation of transfusion by the process I have described, is at once as simple as it is effectual; and in sinking from loss of blood it has this advantage, that to the new charge of blood there is added an agent having the property of stimulating the flagging heart into renewed force and activity.

* Physiological and Practical Studies. On the Effects of the Horizontal Position of the Body in Syncope. Association Medical Journal, July 7, 1854.

VII.

ON SOME CONDITIONS OF THE BLOOD AFTER DEATH, IN RELATION TO MEDICO-LEGAL INQUIRIES.

In sudden death from shock, as by a fall from a height; in instant death from chronic disease of the heart (rupture of the heart excluded); in death from blow on the stomach; and from syncope, the result of terror or emotion, the blood is often found fluid after death.

The cause of this fluidity is simple. It depends, when it is present, on three conditions:

1. That death took place instantly, so that, after absolute death, the blood still remained fluid.

2. That the circulatory system was fully charged with blood, both in the heart and in the vessels belonging to it.

3. And this is most important, that the circulatory system remained, at every part, unopened and perfect.

These three conditions present, the blood will remain more or less fluid, until it is exposed to the air by the dissector's knife; then it will coagulate, as speedily as under any condition, if it is raised to a temperature of 98° Fahr.

The sustainment of the fluidity in these cases depends on simple physical causes, as I have already explained. Consequently, a modification in these conditions may lead to a modification in the condition of the blood, although the cause of death may be virtually the same that is to say, by shock.

For example, if death occur from a fall, and in the fall a wound be inflicted laying open the circulatory canals, the blood will not remain fluid, as it would if no

such complication had happened. Or, if the death is not instantaneous, so that the circulation and respiration feebly continue for a time, the fluidity will be less marked. Again, if the vessels or chambers of the heart are, at the moment of sudden death, but partly filled with blood, as when death takes place during contraction of the ventricles, the blood will not retain its fluidity. Hence, also, when it so occurs, and this is not uncommon, that the right side of the heart and the venous trunks are left at death distended with blood, while the left side and the arteries are comparatively empty, the blood on the right side remains fluid, that on the left side is firmly coagulated.

After death by the alkalies as poisons, the blood is fluid, and the corpuscles are modified in the way already described. The poison of the cobra di capello is followed by similar results. In slow poisoning with antimony the same general rule obtains, both as regards fluidity of blood and condition of corpuscles. If the blood in these cases is coagulated, the coagula are dark and very loose.

In poisoning by chloroform, hydrocyanic acid, opium, carbonic acid, belladonna, arnica, tobacco, and narcotics generally, the blood is dark, and either fluid or loosely coagulated. Belladonna and arnica exert an effect on the corpuscles, seeming to reduce these in number, and to lead, in some cases, to the excessive development of particles of hæmatocrystallin.

In death by hanging or strangulation, if the fatal result be suddenly brought about, there is left a fluid or semi-coagulated condition of blood.

There are three modes in which death may be produced by hanging. 1. Pure asphyxia, from pressure

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