of waste matter from the system; secondly, as a joint regulator of the heat of the body; thirdly, as an agent of absorption; and, fourthly, as the seat of sensation and touch.

"Besides performing the mechanical office of a shield to the parts beneath, the skin is admirably fitted, by the great supply of blood which it receives, for its use as a secreting and excreting organ. The whole animal system is in a state of constant decay and renovation; and while the stomach and alimentary canal take in new materials, the skin forms one of the principal outlets or channels by which the old, altered, or useless particles are eliminated from the body. Every one knows that the skin perspires, and that checked perspiration is a powerful cause of disease and of death; but few have any just notion of the real extent and influence of this exhalation, such as we shall attempt to exhibit it. When the body is overheated by exercise in warm weather, a copious sweat soon breaks out, which, by carrying off the superfluous heat, produces an agreeable feeling of coolness and refreshment. This is the higher and more obvious degree of the function of exhalation; but, in the ordinary state, the skin is constantly giving out a large quantity of waste materials by what is called insensible perspiration, a process which is of great importance to the preservation of health, and which is called insensible, because the exhalation, being in the form of vapor, and carried off by the surrounding air, is invisible to the eye; but its presence may often be made manifest even to sight by the near approach of a dry cool mirror, on the surface of which it will soon be condensed so as to become visible. "Many attempts have been made to estimate accurately the amount of exhalation carried off through the skin. The celebrated Lavoisier and M. Seguin entered this field of inquiry with great success, and were the first to distinguish between the cutaneous and pulmonary exhalations; M. Seguin shut himself up in a bag of glazed taffetas which was tied over his head and provided with a hole, the edges of which were glued to his lips, so that the pulmonary exhalations might be thrown outward, and the cutaneous alone be retained in the bag. He first weighed himself and the bag in a very nice balance at the beginning of the experiment; then at the end of it, when he had become lighter in proportion to the quantity of exhalation thrown out by the breathing; and lastly he weighed himself out of the bag, to ascertain how much weight he had lost in all; by subtracting the loss occasioned by the lungs, the remainder of course exhibited the amount carried off by the skin. He attended minutely also to the collateral circumstances of diet, temperature, &c, and allowance being made for these, the results at which he arrived were the following :

"The largest quantity of insensible perspiration from the lungs and skin together amounted to thirty-two grains per minute, three ounces and a quarter per hour, or five pounds per day. The smallest quantity observed amounted to one pound eleven and a half ounces per day, of which the skin furnished about twenty ounces. The medium was from the skin thirty-three ounces per day.

"What we have considered relates only to the insensible perspiration. That which is caused by great heat or severe exercise is evolved in much greater quantity; and by accumulation at the surface, it becomes visible, and forms sweat. In this way, a robust man may lose

two or three pounds' weight in the course of one hour's severe exertion; and if this be suddenly checked, the consequences in certain states of the system are often of the most serious description. When the surface of the body is chilled by cold, the blood-vessels of the skin become contracted in their diameter, and hinder the free entrance of the red particles of the blood, which are therefore of necessity collected and retained in greater quantity in the internal organs, where the heat varies very little. The skin consequently becomes pale, and its papillæ contract, forming by their erection what is called the goose's skin. In this state it becomes less fit for its uses; the sense of touch can no longer nicely discriminate the qualities of bodies, and a cut or bruise may be received with comparatively little pain. From the oppression of too much blood, the internal organs, on the other hand, work heavily the mental faculties are weakened, sleepiness is induced, respiration is oppressed, the circulation languishes, and digestion ceases; and if the cold be very intense, the vital functions are at last extinguished without pain, and without a struggle. This is a picture of the extremes; but the same causes which in an aggravated form occasion death, produce, when applied in a minor degree, effects equally certain, although not equally marked or speedy in their appearance.

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Taking even the lowest estimate of Lavoisier, we find the skin endowed with the important charge of removing from the system about twenty ounces of waste matter every twenty-four hours; and when we consider that the quantity not only is great, but is sent forth in so divided a state as to be invisible to the eye, and that the whole of it is given out by the very minute ramifications of the blood-vessels of the skin, we perceive at once why these are so extremely numerous that a pin's point cannot touch any spot without piercing them; and we see an ample reason why checked perspiration should prove so detrimental to health,-because for every twenty-four hours during which such a state continues we must either have twenty ounces of useless and hurtful matter accumulating in the body, or have some of the other organs of excretion grievously overtasked, which obviously cannot happen without disturbing their regularity and well-being. People know the fact, and wonder that it should be so, that cold applied to the skin, or continued exposure in a cold day, often produces a bowel complaint, a severe cold in the chest, or inflammation of some internal organ; but were they taught, as they ought to be, the structure and uses of their own bodies, they would rather wonder that it did not always produce one of these effects.

"The function next to be noticed, viz., absorption, is, in some mea. sure, the opposite of the last. By its instrumentality, substances placed in contact with the skin are taken up and carried into the general circulation, either to be appropriated to some new purpose, or to be subsequently thrown out of the body.

"The process of absorption is carried on by vessels fitted for the purpose, which are thence named absorbent vessels, or simply absorbents. In the skin they are so exceedingly small and numerous, that when injected with mercury the surface is said by Dr. Gordon to resemble a sheet of silver. In health they are of too small a size to admit the red particles of the blood, and hence, from,

their contents being nearly transparent, they are sometimes named lymphatics.

"When the perspiration is brought to the surface of the skin, and confined there either by injudicious clothing or by want of cleanliness, there is much reason to suppose that its residual parts are again absorbed, and act on the system as a poison of greater or less power, according to its quantity and degree of concentration, thereby producing fever, inflammation, and even death itself; for it is established by observation, that concentrated animal effluvia form a very energetic poison. The fatal consequences which have repeatedly followed the use of a close water-proof dress by sportsmen and others, and the heat and uneasy restlessness which speedily ensue where proper ventilation is thus prevented, seem explicable only on some such principle." Our author next proceeds to consider the skin as an instrument of sensation. We have only room for the following extract under this head ::-

"Invalids and literary men often suffer severely from excess of action in the brain, and deficiency of activity in the nerves of the skin and remoter organs. The nervous stimulus, which is essential to digestion and to the health and warmth of the skin, cannot be provided when the brain is too exclusively exercised in thinking or feeling; and for want of this stimulus, the tone of the digestive and cutaneous organs is greatly reduced,-the surface of the body becomes cold, shrunk, and uncomfortable, and the individual subject to annoy. ance and painful sensations from trifles which formerly gave pleasure. Bad digestion and deficient warmth of surface are thus proverbially complained of among literary and sedentary persons, and can be removed only by exciting the nervous and vascular functions of the skin, and diminishing those of the brain."

The following observations of our author on dress, bathing, and wet and cold feet, are worthy of the most serious attention:

"The insensible perspiration being composed of a large quantity of water, which passes off in the form of vapor and is not seen, and of various salts and animal matter, a portion of which remains adherent to the skin, the removal of this residue by washing becomes an indispensable condition of health, the observance of which, particularly in early life, when waste and nutrition are both very active, prevents the appearance of cutaneous and other diseases common in infancy. Not only, therefore, is daily washing of the body required at that age, but a frequent change of clothing is essential, and every thing in the shape of dress ought to be loose and easy, both to allow free circulation through the vessels, and to permit the insensible perspiration to have a free exit, instead of being confined to and absorbed by the clothes, and held in contact with the skin, as often happens, till it gives rise to irritation.

"In youth, the skin is still delicate in texture and the seat of ex. tensive exhalation and acute sensation, but it is at the same time more vigorous in constitution than it was in infancy; and the several animal functions being now more equally balanced, it is less susceptible of disorder from external causes, and can endure with impunity changes of temperature which, either at an earlier or more advanced age, would have proved highly injurious. The activity and restless energy

of youth keep up a free and equal circulation even in the remotest parts of the body, and this free circulation in its turn maintains an equality of temperature in them all. Cold bathing and lighter clothing may now be resorted to with a rational prospect of advantage; but when, from a weak constitution or unusual susceptibility, the skin is not endowed with sufficient vitality to originate the necessary reaction, which alone renders these safe and proper,when they produce an abiding sense of chillness, however slight in degree, we may rest assured that mischief will inevitably follow at a greater or shorter distance of time. Many young persons of both sexes are in the habit of going about in winter and in cold weather with a dress light and airy enough for a northern summer, and they think it manly and becoming to do so; but those who are not very strongly constituted suffer a severe penalty for their folly. The necessary effect of deficient circulation and vitality in the skin is to throw a disproportionate mass of blood inward; and when this condition exists, insufficient clothing perpetuates the evil, until internal disease is generated, and health irrecoverably lost. Insufficient clothing not only exposes the wearer to all the risk of sudden changes of temperature, but it is still more dangerous (because in a degree less marked, and therefore less apt to excite attention till the evil be incurred) in that form which, while it is warm enough to guard the body against extreme cold, is inadequate to preserve the skin at its natural heat. Many youths, particularly females and those whose occupations are sedentary, pass days, and weeks, and months without ever experiencing the pleasing glow and warmth of a healthy skin, and are habitually complaining of chillness of the surface, cold feet, and other symptoms of deficient cutaneous circulation. Their suffering, unfortunately, does not stop here, for the unequal distribution of the blood oppresses the internal organs, and too often, by insensible degrees, lays the foundation of tubercles in the lungs, and other maladies, which show themselves only when arrived at an incurable stage. Young persons of a consumptive habit will generally be found to complain of this increased sensibility to cold, even before they become subject to those slight catarrhal attacks which are so often the immediate precursors, or rather the first stages, of pulmonary consumption. All who value health, and have common sense and resolution, will therefore take warning from signs like these, and never rest till equilibrium of action be restored. For this purpose, warm clothing, exercise in the open air, sponging with vinegar and water, the warm bath, regular friction with a flesh-brush or hair-glove, and great cleanliness, are excellently adapted.

"But while sufficiency of clothing is attended to, excessive wrapping up must be as carefully avoided. Great differences in the power of generating heat and resisting cold exist in different individuals, and it would be absurd to apply the same rules to those who never feel cold as to those who are peculiarly sensitive. The former might be benefited by cold bathing and degrees of exposure which would be fatal to the latter. The rule is, therefore, not to dress in an invariable way in all cases, but to put on clothing in kind and quantity sufficient to the individual case to protect the body effectually from an abiding sensation of cold, however slight. Warmth, however, ought not to be sought for in clothing alone. The Creator has made exercise essential as a means ;

and if we neglect this, and seek it in clothing alone, it is at the risk or rather certainty of weakening the body, relaxing the surface, and rendering the system extremely susceptible of injury from the slightest accidental exposures, or variations of temperature and moisture. Many good constitutions are thus ruined, and many nervous and pulmonary complaints brought on, to imbitter existence, and to reduce the sufferer to the level of a hot-house plant.

"Female dress errs in one important particular, even when well suited in material and in quantity. From the tightness with which it is made to fit on the upper part of the body, not only is the insensible perspiration injudiciously and hurtfully confined, but that free play between the dress and the skin which is so beneficial in gently stimulating the latter by friction on every movement of the body is altogether prevented, and the action of the cutaneous nerves and vessels, and consequently the heat generated, rendered lower in degree than would result from the same dress worn more loosely. Every part and every function are thus linked so closely with the rest, that we can neither act wrong as regards one organ without all suffering, nor act right without all sharing in the benefit.

"We can now appreciate the manner in which wet and cold feet are so prolific of internal disease, and the cruelty of fitting up schools and similar places without making adequate provision for the welfare of their young occupants. The circumstance in which wet and cold feet are most apt to cause disease is where the person remains inactive, and where, consequently, there is nothing to counterbalance the unequal flow of blood which then takes place toward the internal parts: for it is well known that a person in ordinary health may walk about or work in the open air with wet feet for hours together without injury, provided he put on dry stockings and shoes immediately on coming home. It is therefore not the mere state of wetness that causes the evil, but the check to perspiration and the unequal distribution of blood to which the accompanying coldness gives rise. Wet and damp are more unwholesome when applied to the feet than when they affect other parts, chiefly because they receive a large supply of blood to carry on a high degree of perspiration, and because their distance from the heart or centre of circulation diminishes the force with which this is carried on, and thus leaves them more susceptible of injury from external causes. They are also more exposed in situation than other parts of the skin; but cold or wet applied anywhere, as to the side for instance, either by a current of air or by rain, is well known to be pernicious.

"The advantages of wearing flannel next the skin are easily explicable on the above principles. Being a bad conductor of heat, flannel prevents that of the animal economy from being quickly dissipated, and protects the body in a considerable degree from the injurious influence of sudden external changes. From its presenting a rough and uneven though soft surface to the skin, every movement of the body in labor or in exercise gives, by the consequent friction, a gentle stimulus to the cutaneous vessels and nerves, which assists their action, and maintains their functions in health; and being at the same time of a loose and porous texture, flannel is capable of absorbing the cutaneous exhalations to a larger extent than any other material in