42 THE INTEGUMENT, OR SKIN. 



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. 



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 liabil- 

 ities of these parts to injury, are thus kindly provided for 

 by " the Hand that made us." 



4. The cutis, or true skin, lies beneath the epidermis, 

 and is its origin and support. It is firm, dense, elastic, 

 very sensitive, and is freely supplied with blood-vessels. 

 It is closely connected with the tissues below it, but may 

 be separated by means of a sharp instrument. The surface 

 of the cutis is not smooth, but is covered here and there 

 with minute elevations, called papillce. These are arranged 

 in rows, along fine lines, or ridges, such as those which 

 mark the palm and fingers ; their number is about 80 to 

 the square line (a line being one-tAvelfth of an inch). 

 These papillce contain the blood-vessels which carry the 

 supply of blood needed by the ever-wasting skin. They 

 contain nerves also, and are largely concerned in the 

 sense of touch; hence they are particularly abundant 

 where the touch is most delicate, as at the ends of the 

 fingers. 



5. The Nails and Hair, These are appendages of the 



3. Wearing out of the cuticle ? What then ? Variety in thickness of cuticle r 

 How accounted for? 



4. Location and office of the cutis? What further is said of it? Papillae? 

 Touch ? 



5. What are the nails and hair ? The growth of the nail ? The rapidity of it3 

 growth 2 Accident to the nail ? 



