For many persons, cotton and linen are found to be more restful, for night wear, than garments made of wool. Even when woolen underclothing is worn with comfort and satisfaction during the day, there is, to some persons, a pricking sensation, a slight surface irritation, in the use of woolen night wear which is destructive of rest. The activities of the skin, as well as the other bodily functions, require a measure of repose. The old, the delicate, and the very young may use a light woolen night-dress outside that of linen or cotton. If comfort demands the use of wool next to the skin, it should be light in weight, finely woven, and with a smooth surface. Cleanliness and health alike demand that no part of the clothing worn during the day should be worn while sleeping. The garments worn in the day should be thoroughly aired and dried during the night, and the moisture absorbed by the night clothing should be allowed to evaporate, and the garments ventilated during the day. In cold climates and in cases of sickness, weakness, or of delicate constitution, the dress of the night as well as of the day must be adapted to the requirements of the case. =Hats.=--In the advancement from barbarism to civilization, the head was the last part of the body to be covered. Nature originally furnished, in the form of a thick mat of hair, all the covering that was necessary for the head. Baldness was then unknown. While the demands of modern society must be complied with, and hats must be worn, the nearer we can approach to Nature’s plan the better. A hat should be light, loose, and well ventilated. A heavy hat presses with undue weight upon the scalp. A tight-fitting hat interferes with the free circulation of the blood. A hat that is close in its texture, prevents the escape of the heated air within, and not only produces a sense of oppression but is believed to be the most fertile cause of baldness. Silk hats for men are especially objectionable on this ground. All close hats should be supplied with efficient means of ventilation. The head, like any other part of the body, perspires, and if the hat is removed in a cooler atmosphere or in a current of wind, a cold in the head is apt to follow. The chief cause of baldness is pressure of the hat, which constricts the blood vessels and so interferes with the nutrition of the hair bulbs. It is probable, also, that the shutting off of air and light by the hat promotes baldness. An unhealthy condition of the scalp results, the sign of which is an excess of dandruff.