3. It causes contraction of the capillaries, and thus lessens the superficial circulation, and stops the cutaneous secretion.
4. It probably destroys the principle of vitality, equally in every part, and does not exclusively disturb the functions of any particular organ.
These positions have been confirmed by experiment. Dr. Chassat states that in an animal immersed in a cold bath, death may take place at 79° Fahr. (26 Centig.), although it may be sometimes cooled down as low as 69° (17 Cent.) before it dies; but, cæteris paribus, the animal dies sooner as the cooling is more rapid.
M. Portal thinks that cold produces death by inducing apoplexy, and remarks that the examination of the bodies of persons who have died from cold, proves the presence of sanguineous congestions in the vessels and cavities of the body, and especially in those of the brain. Dr. Cooke, however, has remarked that “M. Portal’s notions on this subject seem to want confirmation. Excessive cold undoubtedly produces, first drowsiness and afterwards a profound sleep, in which the unfortunate individual generally perishes; but we have not on record a sufficient number of cases with particular descriptions of symptoms and appearances on dissection, to enable us to say positively that cold kills by apoplexy.”
After death the blood is generally florid in the aorta, so that the animal does not die of suffocation; the heart sometimes contracts feebly after the muscular irritability of the limbs and intestines are nearly destroyed; the cerebral veins contain but little blood; the ventricles contain a small portion of fluid. Mr. Brodie’s experiments coincide in most respects with those of Dr. Chassat, who uniformly found after death, the heart much distended with blood, as in Syncope, scarlet blood occupying the left side; and he also found that the heart ceased to contract before the diaphragm, so that he has seen the animal insensible, and gasp for breath, even after the chest was opened and the heart excised! The muscles were unusually florid, and the peristaltic motions of the intestines were generally observed to continue longer than the action of the heart. The voluntary muscles, he says, lose their irritability in different degrees, those of the legs before those of the thighs, and those of the thighs before the abdominal muscles.
DEATH BY THE AGENCY OF HEAT.
We have not yet a sufficient number of well reported experiments on the effects of heat on animals, to enable us to draw any satisfactory conclusions respecting the mode in which life is destroyed by this agent; although it seems probable that it acts by destroying the muscular energy of the heart and diaphragm.[[53]]
Mr. Brodie placed a rabit in a basket in an oven, the temperature of which was not more that 150°, and it died in a few minutes without any apparent suffering; the heart was afterwards found distended with blood, on both sides, as in Syncope.
DEATH BY LIGHTNING.
It has been incontrovertibly established by the experiments of modern philosophers, that the phœnomena of electricity are identical with those of thunder and lightning. The human body is alike affected by both; and death, whether it be occasioned by the discharge of an electrical battery, or by that of a thunder cloud, exhibits effects precisely analogous.