Clothing must be adapted to the climate in which a person lives. Warm or heavy clothing is rendered imperative in a northern climate, while the lightest and thinnest can only be tolerated in the torrid zones. It is, however, a physiological fact that the more the whole surface of the body is exposed to the external air, within certain limits, the more vigorously is its functional action performed, and the better is it enabled to preserve its own proper temperature, as well as to resist all unwholesome impressions from vicissitudes of weather, or the extremes of heat and cold. It should always be as light and loose as possible without bodily discomfort.

The substances principally employed for clothing are linen, cotton, silk, wool, hair, or down. Woollens or flannels, being bad conductors of heat, afford the greatest immediate protection from cold; and for the same reason are less debilitating to the cutaneous function than is generally supposed. The most healthy clothing for a cold climate, especially the year round, is undoubtedly that made of wool. If worn next to the skin by all classes in summer and winter, an incalculable amount of coughs colds, diarrhoeas, dysenteries, and fevers would be prevented, as also many sudden and premature deaths from croup, diphtheria, and inflammation of the lungs and bladder. Of course, the clothing should be regulated in amount according to the degree of the heat of the weather at the time prevailing. In a very hot day, for instance, a single garment might be sufficient, but on a colder day an additional garment should be added, and in this way keep the equilibrium of the temperature of the body uniform as possible day by day, the year round. Winter maladies would be prevented by the ability of a woollen garment to keep the natural heat about the body, instead of conveying it away as fast as generated, as is done by linen, flaxen, cotton, and silken garments. Indeed, the laboring classes, or those compelled to toil in the sun, would enjoy better health by wearing light woollen clothing, than by wearing linen or cotton fabrics. Among the Irish emigrants and others who arrive in the United States during the summer season, we find many clothed entirely in woollen garments, frequently wearing heavy cloaks or coats, and actually feeling less discomfort from the heat than those of our native-born citizens who are in the habit of wearing linen or cotton next to their skin, and similar fabrics over these for outer clothing. It is more healthful to wear woollen next to the skin, especially in summer, for the reason that woollen textures absorb the moisture of perspiration so rapidly as to keep the skin measurably dry all the time. It is curious to notice that the water is conveyed by a woollen garment from the surface of the body to the outer side of the garment, where the microscope shows it condensed in millions of pearly drops; while it is in the experience of all observant people, that if a linen shirt becomes damp by perspiration, it remains cold and clammy for a long time afterwards, and, unless removed at once, will certainly cause some bodily ailment, as palsy, rheumatism, etc. To sit down, or remain inactive with a linen or cotton shirt wet with perspiration, will speedily cause a chill to the whole body, leading not unfrequently to some sudden and fatal disease. In the night-sweats of consumption, especially, or of any debilitated condition of the system a woollen or flannel night-dress (light for warm weather) is immeasurably more comfortable than cotton or linen, because it prevents that sepulchral dampness and chilliness of feeling which are otherwise inevitable. The British government make it imperative that every sailor in the navy shall wear flannel shirts in the hottest climates, a rule that should be adopted by all persons everywhere exposed to variable weather, to extreme heats and colds, merely regulating the amount of woollen garments worn to suit the variable temperatures of climates and seasons. In saying all this, however, we must remember that comfort is very much a matter of habit; and therefore we should make due discrimination between the natural sensation of health and the morbid sensitiveness produced by false customs. For instance, some keep their whole bodies constantly covered by many layers of woollen garments, and yet go into a shivering fit at every unusual breath of cold air. The reason is, they never adapt their habiliments gradually to the degree of the heat or cold of the season. If it be deemed advisable to wear woollen clothing all the year round; whether summer or winter, it does not follow that we are to wear more than one or two extra folds of clothing in addition to the under garments. The true rule is not to cover all parts of the body equally with the same amount of clothing. The fleshy parts require the least clothing, and the limbs and feet, of less muscular parts, the most. Yet we often wear, in addition to under-clothing, a thick vest, coat, and overcoat; and to these will add heavy scarfs of fur or wool to the neck, etc., while the legs and feet are seldom clad in more than a single additional garment to the drawers and stockings. These parts require more clothing, especially in the winter season, than any other parts of the body. Furs are worn in the United States more for ornament than benefit. They are the warmest clothing materials known; yet are not adapted for general wear, inasmuch as they are apt to overheat the body, and thus render it keenly susceptible to colds and other afflictions. By consequence, fur neck cloths, caps, etc, are very pernicious for the head and throat, inducing catarrhs, quinsy sore throat, and similar afflictions. On the contrary, a light woollen waist-coat worn constantly oer the breast, summer and winter, would guard against these and other evils, and insure vigorous strength to the lungs or respiratory apparatus, and thus should not be dispensed with even in dog-days. The simple rule is to keep the head cool and the feet warm at all seasons of the year. Cheap and pretty silks, of which there are many varieties, are materials which are admirable for ladies'evening, dinner, or walking dresses, and cost less in the end than other fabrics.

While I contend that woollen or flannel clothing is the most suitable for the colder or even the more temperate climates, it is not for me to object to the use of linen or cotton clothing for those living in the the torrid or tropical climes. Indeed, cotton and linen would seem best adapted to such climes. Such persons usually lead an active, out-door life, or are accustomed to exposing their bodies frequently, especially their chests, to atmospheric influences.

In a strictly hygienic regulation of dress, however, the color of the clothing is not to be disregarded. White color reflects the rays of the sun; black absorbs them. Light colored clothing is, therefore, more comfortable and sanitary in warm weather than dark colored, because the former repels the heat, while it is readily received and retained by the latter. The heat-reflecting or heat-retaining property of different fabrics varies exactly with their lighter or darker shades of color. This difference, however, is much greater in the luminous rays of light than in the non-luminous. When, therefore, we are not exposed to the sun, the subject of color is of very little importance. The absorbing power of dark surfaces renders the skins of dark-colored animals, as well as the darker persons or races of the human family, less liable to be scorched or blistered by the direct rays of the sun than are those of a lighter color.

As to the cut or fashion of garments, that is a matter to be decided by the taste or habits of the wearer. Fashion, however, is very arbitrary, and seldom consults hygiene in matters of dress. Of late years she has really much improved, as to the regulation of attire with regard to both health and elegance. The hooped skirt, which at the outset of its career was so mercilessly ridiculed, has proved to be a great blessing to the ladies, as it enables them to dispense with a heavy drag of solid skirts, and gives their lower limbs free and easy play and motion. The hat or head-coverings now worn by both sexes are, in a sanitary point of view, far superior to those worn by our immediate ancestors, being very light, and affording free ventilation, which is indispensable for the avoidance of headaches, rushing of blood to the head, and many other afflictions.

I can therefore only say that the first physiological rule for dress is to have all garments as light in texture and as loose in fashion as is consistent with bodily comfort, or such as will admit of the most perfect freedom in the exercise of every muscle in the body. Inequality of clothing, as before remarked, is a far more frequent cause of colds than deficient clothing. For instance, if a person exposes a part of the body usually protected by clothing to a strong current of cold air, he will take cold sooner than by an equal exposure of the whole body. A great safeguard against disease is to regulate the texture and quantity of clothing according to the temperature of the climate in which a person lives, avoiding extreme colds or extreme heats; keeping the clothing always fresh and clean (especially that of the feet), and wearing a different garment at night from that worn during the day, not omitting the cleanliness of the whole body in the general hygiene of wearing apparel