Habitual excessive perspiration can, however, impair the skin through the elimination of harmful products, although the skin is, to a certain extent, protected by the greasy matters secreted through the sebaceous glands. Likewise we can also note the loss of hair in persons perspiring very much about the head and more particularly in those parts where the sudorific glands are situated, such as the forehead and temples. This is most frequently observed in those who have dry hair, in whom accordingly there is a diminution of the functions of the sebaceous glands. In persons who wear fur caps and whose head is always covered, we most frequently find bald heads, especially if they have a tendency to perspiring about the head. For this reason it is also more reasonable never to wear hats if we desire to retain as long as possible the natural ornament of the head. We can cause abundant perspiration by all the various means by which the temperature of the body is raised. In such cases more blood comes to the periphery of the body, and thus also to the sudorific glands. The essential factor is the widening of the capillaries, and this can be produced not only by agencies influencing the body from without, such as hot air or a vapor bath, but also by agencies from within the body which act on the vasomotor centers and thereby cause a widening of the capillaries, such as certain drugs like salicylates, and also organic preparations like thyroid extracts; mental emotion will also cause such an occurrence. Salicylates are excellent drugs for producing abundant perspiration, and are also less dangerous than pilocarpine. After the use of the former and very free perspiration, we notice an improvement in the symptoms of gout, for reasons we will give later.