Speaking of the skin of the feet leads me to the subject of the ventilation of boots, which is a very difficult one.
I have said (p. 24) that the perspiratory glands are more numerous on the soles of the feet than on any other part of the body, with the exception of the palms of the hands; hence in the clothing of these parts good facilities for evaporation and transpiration ought to be afforded; but to do this is well-nigh impossible, owing to the fact that it is necessary to protect the feet from injury by contact with stones, broken glass, tacks, and pins, &c. If we could go without boots or shoes entirely the skin of the feet would manufacture a protection for them in the same way as I have above described, by a process of thickening and hardening. As it is, however, boots and shoes are a necessary evil, and we must, therefore, try to make them as little of an evil as possible. Perhaps the most practicable way of allowing for the ventilation of out-door boots is to have merely a golosh of leather affixed to the sole, and the upper part of the boot entirely of cloth. Shoes, leaving the upper part of the foot exposed, of course afford better facilities for transpiration than boots made entirely of leather, and they may be worn in winter with cloth gaiters. For summer wear the uppers of the boots may be made of cashmere. Stockings should always be woollen, and boots and shoes should also be lined with woollen materials if practicable. When the feet are warm and damp from exercise, the stockings and boots should be changed, and even if the