winter clothing, linen and silk for summer. The temperature of the body as a whole is, as we have seen, about 98½ degrees F.; this figure represents the maximum temperature that the skin can reach, even when it is flushed to its utmost. In the warm weather of the summertime the temperature of the air frequently mounts to or even above that point and it is evident that under such circumstances the body cannot give heat directly from itself to the surrounding air, and no amount of flushing of the skin will enable it to do so. It is under these circumstances that the second method of getting rid of heat comes into play, namely, the evaporation of sweat. We have spoken of the sweat glands in a previous chapter, but have left their action and the description of the skin in which they lie for this point. The skin serves a number of purposes; it is the great protective layer for all the parts beneath; in order that it may serve for this it must itself be reasonably free from injury. This is secured by having the outer layers of the skin composed of a horny dead material. Just beneath this dead layer is a layer of living cells tightly packed together and having exposure to the body fluids only at their under side. Cell multiplication goes on in these cells continuously and rapidly; as the cells divide, they grow, the result being that those that are underneath are constantly crowding those above them farther and farther out toward the surface; this cuts them off from their food supplies and so they die. This layer of dead cells becomes very closely packed and makes up what is commonly called the horny layer of the skin or the “cuticle.” The outer part of this cuticle is constantly rubbing off and, of course, as this happens any dirt that may be clinging is rubbed off as well. A large factor of cleanliness is the constant rubbing off from the surface of the body of its outermost layer. The extent to which this happens can be appreciated by anyone who has ever had a broken bone and has had to have an arm or leg put up in a splint or cast for several weeks. At the end of that time there is a great accumulation of dead skin waiting to be rubbed off.