found to be absorbed; but such absorption neither interferes with nor militates against an increased amount of secretion from the cutaneous exhalants. If the body is immersed in cold water, under the same circumstances of general vigour of the system, and an active surface-circulation, the first effect is a rapid chilling, obviously dependent on the fact that the water is so much better a conductor of heat than the air is. The degree of the chilling effect corresponds with the powers of the system, the previous heat of the body, the fulness or emptiness of the stomach, and the temperature of the water. In consequence of the effect produced by immersion in cold water on the temperature of the body, there is a great influence exerted on the circulation of the blood, and on the nervous system. The first effect of the cold water on the circulation is that the passage of the blood through the superficial vessels is checked; its secretions are possibly arrested altother, and in all cases are largely diminished; and a correspondingly considerable proportion of the blood of the system is determined to the tissues and organs in the interior of the body. This may be ascribed to an extreme spasmodic action of the vessels of the skin, and the resulting interruption of their primary and secondary functions. If the water is not extraordinarily cold, and the powers of the heart and arteries are in full vigour, these are roused by the sudden rush of blood into them, to an unusual degree of effort; and the blood is driven back again to the vessels of the surface, and even in an unwonted

IMMERSION IN COLD WATER.

215

degree of volume and rapidity; the warmth of the surface is regained; and re-action is said to have taken place. This restored equilibrium of the circulation will continue to obtain during a longer or shorter time, according to circumstances; and at length, if the immersion in the cold water is continued, the energies of the circulating organs become no longer able to counteract the cooling effects of so good a conductor of heat as the water; they are no longer able to dispose of the quantity of blood which the rapidly refrigerating effect of the water on the surface is continually throwing back upon them; they become more and more loaded with blood; their action becomes gradually more oppressed and less energetic; the skin is once more chilled, and its circulation is once again languid; and shivering, loss of feeling, stupor, and, the cause still continuing, death ensues.

Besides this effect of immersion in cold water on the superficial and general circulation, there is an undoubted and simultaneous effect produced by it on the nervous system, the character of which is sufficiently understood by the word shock. This effect is depressing, and is of the same kind as results from any severe or sudden sensations, although it may be greater or less in its degree. The influence of a shock to the nervous organism, from extensive injury, or very violent impressions on the organic sensibilities, may be so great as to destroy life, without affording time for the action of any lesion, or the disturbance of any function, to contribute in any

may

degree to the fatal result. Although in the case of immersion in cold water, the severity of the shock be rarely sufficient to act singly in producing any serious or lasting impression on the system, it may be admitted that it will contribute in an important degree to the bad consequences of the derangement of the general circulation of the blood, and the general derangement of the system, in cases where general debility, or general congestion, or a disordered condition of any of the great or vital organs, serves to interfere with, or prevent, the prompt supervention of such a degree of re-action as may serve to restore the balance and equilibrium of the circulation, to relieve the engorgement of the internal organs, and to secure a vigorous action of the blood-vessels of the skin.

Certain conditions are more or less necessary, in order to render re-action prompt, efficient, and secure, in the case of immersion in cold water.

There are

1st. A due adaptation of the temperature of the water to the circumstances of the case. few persons who can bathe with perfect safety in water of a lower temperature than 60 degrees. The heat of the human body being generally about 98 degrees, an immersion in water of the temperature of 80 degrees will usually feel at first somewhat cold to the bather. The degree to which this sense of coldness is felt on immersion in water of a given temperature, will depend very much on the temperature of the air. Water of the same heat will seem much warmer to the bather in winter

RE-ACTION AFTER THE COLD BATH. 217

than in summer time. Provided a sufficiently prompt and an efficient degree of re-action is established, and provided there is no organ or function in such a state as to be impaired by the influx of blood determined at the instant of immersion to the internal parts of the body, the colder the water of the bath, within certain bounds, the greater and more genial will be the degree of re-action.

2nd. The colder the water of the bath, the shorter, other things being equal, should be the period of the immersion. It is seldom prudent to remain longer than ten minutes in a cold bath; and this may prove to be much too long an immersion for an invalid, who might be justified in using the cold bath for a shorter period.

3rd. The effect of the cold bath on the system varies according to the degree of energy with which the heart and arteries are acting at the time of using it. There can hardly be a more dangerous step, than to make use of the cold bath when the body is fatigued,-whether from excessive muscular exertion, or from heat, or from long continued mental exertion, or from loss of sleep, or however else brought about. In this case, the re-action may be imperfect, or only partial; and shiverings and great prostration of strength may be followed by local determination of blood, and febrile or inflammatory conditions. This may be well illustrated by the case of the late Dr. Currie, as recorded by himself in his admirable "Medical Reports." "On the first of September, 1778, two students of medicine at Edinburgh set out on foot on a journey, a considerable part of which

lay along one of the rivers of Scotland (the Tweed; -the journey having been from Edinburgh to Moffat). They started by sun-rise, and proceeded with alacrity in the cool of the morning. At the end of eight miles they breakfasted, rested for an hour, and then resumed their journey. The day grew warm as it advanced, and after a march of eight miles more, they arrived, heated, but not fatigued, on the banks of the river above-mentioned, about eleven in the forenoon. Urged by the fervour of the day, and tempted by the beauty of the stream, they stripped instantly, and threw themselves into the river. The utmost refreshment followed; and when they retired to the neighbouring inn, this was succeeded by a disposition to sleep, which they indulged. In the afternoon they proceeded, and, travelling sixteen miles farther at a single stretch, arrived at the inn where they were to sleep, a little after sunset. The afternoon had been warm, and they perspired profusely; but the evening was rather temperate and cool. They had travelled for some miles slowly, and arrived at the end of their journey stiffened and wearied with their exercise. The refreshment which they had experienced in the morning from bathing induced, however, one of them to repeat the experiment, and he went perfectly cool into the same river, expecting to relax his limbs in the water, and afterwards to enjoy profound sleep. The consequences were very different. The Tweed, which was so refreshing in the morning, now felt extremely cold, and he left the water hastily. No genial glow succeeded, but a