they generate. There are many physical rules and precautions which are advocated, not without reason, as tending to inhibit or diminish sexual activity. The avoidance of heat and the cultivation of cold is one of the most important of these. Hot climates, a close atmosphere, heavy bed-clothing, hot baths, all tend powerfully to excite the sexual system, for that system is a peripheral sensory organ, and whatever stimulates the skin generally, stimulates the sexual system.[99] Cold, which contracts the skin, also deadens the sexual feelings, a fact which the ascetics of old knew and acted upon. The garments and the posture of the body are not without influence. Constriction or pressure in the neighborhood of the sexual region, even tight corsets, as well as internal pressure, as from a distended bladder, are sources of sexual irritation. Sleeping on the back, which congests the spinal centres, also acts in the same way, as has long been known by those who attend to sexual hygiene; thus it is stated that in the Franciscan order it is prohibited to lie on the back. Food and drink are, further, powerful sexual stimulants. This is true even of the simplest and most wholesome nourishment, but it is more especially true of flesh meat, and, above all, of alcohol in its stronger forms such as spirits, liqueurs, sparkling and heavy wines, and even many English beers. This has always been clearly realized by those who cultivate asceticism, and it is one of the powerful reasons why alcohol should not be given in early youth. As St. Jerome wrote, when telling Eustochium that she must avoid wine like poison, "wine and youth are the two fires of lust. Why add oil to the flame?"[100] Idleness, again, especially when combined with rich living, promotes sexual activity, as Burton sets forth at length in his _Anatomy of Melancholy_, and constant occupation, on the other hand, concentrates the wandering activities.