8. DEATH BY EXPOSURE TO COLD.
That an animal must perish as soon as the temperature of the medium in which it lives ceases to preserve the blood in a state of fluidity, is one of those self-evident propositions which scarcely requires notice, much less explanation; but that a degree of cold not sufficiently intense to occasion any physical changes upon the constituent parts of the body should extinguish its vitality is a fact, whose history involves some of the most interesting questions of physiology.
The degree of cold, necessary for the production of its fatal effects, varies in a very remarkable degree with the strength and circumstances of the individual to whom it is applied, as well as with the rapidity of the cooling process. In some instances we find that man has endured an extreme degree of cold with but little inconvenience, whilst in other cases, we see him perishing from it in a temperature at which water even retains its fluidity. The interesting history of Sir Joseph Bankes (at that time Mr. Bankes), Dr. Solander, and eleven others, on a botanical excursion to the mountains of Terra del Fuego; and more recently, the narrative of our enterprizing countrymen, in their voyage to the Polar seas, will furnish a good illustration of the former fact, whilst the melancholy fate of the Cambridge student, as hereafter explained, affords a curious and instructive example of the latter. Animal heat, as Mr. Brodie observes, is in some way or other dependant upon the integrity of the functions of the Nervous System; and consequently the absolute degree of cold which an animal can bear with impunity will, cæteris paribus, be determined by his powers of producing heat; we must therefore cease to regard the fact as extraordinary, that an animal, which is under the influence of a deleterious narcotic poison, or in whom, from any other morbid cause, the powers of the nervous system are exhausted, may be destroyed by a diminished temperature, that would scarcely affect even the sensations of one, differently placed in relation to his nervous energy; thus it is with a person in the last stage of intoxication, in whom the powers of life are ebbing, in consequence of the previous state of morbid excitement; in the course of the last winter, two instances occurred of drunken persons being taken to the watch-house; where, there not being any charge against them, they were dismissed by the constable of the night, and perished in the streets. A military friend has lately communicated to us an instance, where out of a great number of troops who were exposed to intense cold, the only one who perished was under the influence of intoxication; and we learn from Le Baume’s interesting account of the campaign in Russia, that similar results were observed during the disastrous retreat of the French army on that memorable occasion.
In our own country scarcely a winter passes without the occurrence of some event equally illustrative of this physiological fact; and it is highly important that the medical jurist should be able to appreciate its influence; those who perish in this manner are generally individuals of the most wretched condition, and will be found to have undergone much suffering and privation; by which their nervous energy had been too much exhausted to generate sufficient heat to counteract the diminished temperature of the atmosphere; an event of this nature occurred in London during the winter of 1819, when a man and his wife, aged persons, and poor, but not supposed, nor indeed proved to have been quite destitute, were found dead in their apartment, although food was discovered in the room, and money was in the pocket of the man: the night (28th of December) had been inclement, and there was neither bed nor fire in the miserable couple’s apartment. It appeared in evidence that they had been previously ailing. The verdict recorded that they had perished from the inclemency of the weather, in consequence of the destitute circumstances under which they were found.
It would seem that persons who are long exposed to intense cold do not suffer a painful death; they gradually lose their sensibility, become drowsy, and die as if through the effects of an opiate. Mr. Brodie[[52]] classes the effects of cold in the following order.
1. It lessens the irritability, and impairs the functions of the whole nervous system.
2. It impairs the contractile powers of the muscles.
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.