BED AND BED-CLOTHES. 199 knows how essential are rest and quietude, and a total avoidance of all excitement, whether mental or bodily, to many cases of disordered health. The consequence is, that many are ordered, under such circumstances, to lie in bed altogether. By and by, treatment and time remove the active or inflammatory character of the ailment, and a considerable degree of languor and exhaustion is experienced, or a high amount of irritability; and these conditions are followed by much prostration of the vital energies. I have reason to know that a patient may sink from these causes, and these causes only; and it is much more frequently the case that the continuance of this greatly enfeebled condition of the system, a condition so notoriously and remarkably predisposing to the occurrence of organic disease, leads to the lapsing of the constitution into such a permanently incurable condition. It is a matter of constant observation, how very slowly patients progress in their convalescence, until they have left their beds, and have managed to recline, for a longer or a shorter time every day, on the sofa. It repeatedly occurs, that the nights and days are alike sleepless, the bowels obstinately costive, all the secretions (unless those of the skin) scanty, and the feelings depressed, until the patient is got out of bed for an hour or two every day, and the vessels of the skin, and the system generally, are relieved from the exhausting effect of the bed and the bed-clothes. While it is needful for every one to keep his surface warm in bed, yet this may be carried too far; or the necessity for more than a certain amount of such means may be materially diminished. A free and sufficient use of exercise, and particularly walking exercise; a regular exposure to the open air; a daily change of air, as far as may be practicable,—walking as far away from home as strength, and time, and weather allow, instead of confining the exercise to a circle near the house; and a regulated diet; are the great means, next to sufficiently frequent ablutions, of keeping the vessels of the skin in a state of efficient activity, and preserving or restoring the natural temperature of the surface. And, this point having been gained, very few and light bed-clothes are all that will be required; the system, having been sufficiently exhausted of its vital energies by the day's work, will need no bed of down to lull or soothe it to repose; and a hair mattress, a sheet, blanket, and counterpane, will generally suffice to defend the body from the ruder approaches of the cold air, even during sleep, and in the coldest of our wintry nights. Without such regular use of nature's opiates, the skin is easily chilled, and the body must be buried in a soft bed, and covered with heaps of bed-clothes; and then re-action comes on, and the skin becomes hot, the system feverish, the sleep disturbed, and the man rises comparatively unrefreshed, and perhaps unable to prosecute his studies or his business. The system is perhaps relieved for the time by medicine; until, too often so treated, the constitution becomes injured, or, it may be, eventually broken up. I would not be understood to advise, that the bed of feathers or of BED AND BED-CLOTHES. 201 down, and the three or four blankets, to which any one may have been accustomed, should be abandoned at once, without preparation, whatever the age, or the habits, or the ailments, of the individual. The doing so must be prepared for, by a regular diet, exercise in the open air, judicious clothing, &c.; and then, gradually, blanket after blanket may be safely, and without discomfort, dispensed with; and, last of all, the hair mattress may be put on the feather-bed, instead of the bed on the mattress. But, however great may be the caution needful with regard to the debilitated adult, comparatively little of such caution will be found to be needful in the case of children, after the periods of infancy and earlier childhood shall have been passed. During the earlier periods of life, the young require much fostering means of protection and warmth; but this is very much less the case afterwards. I would, then, by good and active nursing, by daily exposure to the air and the light, by the liberal and daily application of tepid water (temperature 70 to 80 degrees) to the whole surface of the body, by keeping the stomach free from all trash, as sugar, &c., strive to regulate and give tone to the several functions; and it may be relied upon that no heating bed will such children require after the age of infancy, no multiplicity of bed-clothes will they need; and a hair mattress and few bed-clothes will suffice to keep up the heat of their surface, without irritating or weakening the system. The two ways in which substances part with their elevated temperature to the colder bodies around them, have been mentioned; and the more important of these ways, that of the conduction of the heat from particle to particle of the colder atoms of the surrounding bodies, has been sufficiently taken notice of. Substances part with their heat to colder bodies, not only by contact, but in rays, proceeding from all points of their surface, in all directions. This is well known as radiated heat; and the bodies are said to part with their heat by radiation. Not only, however, do different substances part with their heat in this way, with different degrees of quickness; not only does the degree of quickness differ, as the heated substances are more or less thick, or as their surface is more or less rough; but they part with their heat by radiation with different degrees of quickness, according to the colour of the surface, according to the ray or rays of light which the surface of the heated substance reflects. Little has been added to our knowledge of these facts, since the experiments and discoveries of the late Professor Leslie, made public in 1804; but the subject has been illustrated and confirmed by the experiments of Dr. Stark, of Edinburgh, published in the "Philosophical Transactions" for 1833. It may be enough to mention here, that white surfaces both radiate most slowly, and absorb radiant heat most slowly; and that black surfaces, on the contrary, both radiate most quickly, and absorb radiant heat most quickly. In Dr. Stark's experiments, the bulb of a delicate thermometer was successively surrounded by equal weights of differently COLOUR OF THE CLOTHES. 203 coloured wool, and placed in a glass tube, and heated, by immersion in hot water, to 180 degrees, and then cooled to 50 degrees, in cold water. The times of cooling were found to be, 21 minutes with the black wool, 26 minutes with the red wool, and 27 minutes with the white wool. Similar results were obtained, when the bulb of the thermometer was surrounded with flour of different colours. Moreover, differently coloured wools having been wound on the bulb of the thermometer, exposed in a glass tube to hot water, the mercury rose from 50 to 170 degrees in the following times :-when surrounded with black wool, in 41,—when with dark green wool, in 5,— when with scarlet wool, in 5,-and when with white wool, in 8 minutes. The practical deductions from these facts are by no means unimportant. In hot weather, and more particularly in the intertropical countries, it may be desirable to wear clothes which will absorb as few of the sun's rays as possible; and white garments are shown to be the best calculated to answer this intention. Again, in cold weather, it is desirable to wear clothes which will part with as little as may be of the heat of the body by radiation; and white articles of clothing are proved to be the best in this instance likewise. The professional man, clad in black, is, strange to say, the most unphilosophically dressed ; for in the summer, his clothes, by absorbing to a great extent the rays of the sun, render him much hotter; and in the winter, his clothes, carrying off by radiation much of his bodily heat, render him |