1. THE INTEGUMENT.--The skin is the outer covering of the body. The parts directly beneath it are very sensitive, and require protection. This is shown whenever by accident the skin is broken, pierced, or torn off, the bared surface being very tender, and painful to the touch. Nature has provided the body with a garment that is soft, pliable, close-fitting, and very thin, and yet sufficiently strong to enable us to come in contact with the objects that surround us, without inconvenience or suffering. [Sidenote: 2. Microscopic examination? What is the cutis? The cuticle? Their union? How separated? What further is said of the cuticle?] 2. THE STRUCTURE OF THE SKIN.--When examined with the aid of the microscope, the skin is found to be made up of two layers--the outer and the inner. The inner one is called the _cutis_, or true skin; the outer one is the _epidermis_, or scarf-skin. The latter is also known as the _cuticle_. These two layers are closely united, but they may be separated from each other. This separation takes place whenever, from a burn, or other cause, a blister is formed; a watery fluid is poured out between the two layers, and lifts the epidermis from the true skin. Of the two layers, the cuticle is the thinner in most parts of the body, and has the appearance of a whitish membrane. It is tough and elastic, is without feeling, and does {42} not bleed, when cut. Examine it more closely, and we observe that it is composed of minute flat cells, closely compacted, and arranged layer upon layer. [Sidenote: 3. Wearing out of the cuticle? What then? Variety in thickness of cuticle? How accounted for?] 3. The outer layer is constantly being worn out, and falls from the body in the form of very fine scales. It is, also, continually forming anew on the surface of the inner layer. Its thickness varies in different parts of the body. Where exposed to use, it is thick, hard, and horn-like, as may be seen on the soles of the feet, or on the palms of the hands, especially of those who are accustomed to perform much manual labor. This is an admirable provision for the increased protection of the sensitive parts below the skin against all extraordinary exposure. Even the _liabilities_ of these parts to injury, are thus kindly provided for by "the Hand that made us." [Sidenote: 4. Location and office of the cutis? What further is said of it? Papillæ? Touch?]