Though the lungs perform the main part of the breathing, much is done also by the skin, which has this further function of continually striving to throw off those waste products and impurities of the body which rise like scum to the surface. How vastly important these functions are is shown by the story of Pietro Riario, the boy Cardinal-Archbishop of Florence, who at a feast gilded a child all over to serve as a huge lamp bearer, with the consequence that in a few hours the unfortunate victim died. It is clearly, then, desirable to listen to the demands of the skin, which are as simple and intelligible as those of the lungs, and consist of air, warmth (though to a far less extent than is generally supposed), and cleanliness. It is by clothing and baths that we meet these demands. Now our general method of dealing with the skin is to wrap it up and put it in the dark; in other words we cover it as much as possible, because we say it is delicate and to expose it gives us colds. It is delicate--that is quite true; but what has made it delicate is our habit of covering it up. A woman, for instance, will pass with arms, shoulders, breast, and a large part of the back bare, out of a heated ball-room into a cool sitting-room and not catch cold, because her skin is used to what--as far as the skin is concerned--is most sanitary and healthy treatment. She does not catch cold, because her skin is used to it, and one of the surest ways to guard against colds is deliberately and every day to accustom it to exposure. Reasons of decency forbid us to make this a public performance, but everyone can and should adopt some course of the following kind. Strip completely on getting up and (whether the bath, hot or cold, is taken immediately or not) go through the other incidentals of dressing, shaving, etc., without clothes on. Similarly at night undress completely at once and give the skin ten minutes’ airing before getting into bed. At the same time, it is well to avoid any feeling of chill, and if it is cold, sit before the fire a few minutes, or, better still (unless you find that they keep you awake), have a few minutes at the exercises given above, which will supply a more thorough and invigorating warmth. The effect of this simple treatment is, as we know from personal experience, quite amazing, both in its hardening virtues, whereby we are far less liable to catch cold at sudden chills or changes of temperature, in its tonic effect on the skin itself, as shewn in a vastly increased firmness and elasticity, and also in the constant and immediate feeling of freshness that it produces. We all know how vivifying is fresh air on the face only; here the whole skin is invigorated.