AND PHYSIOLOGY. 



305 



supplied with blood-vessels, as 

 is seen by the cut. 



538 c. Rale of Growth.— 

 In one set of experiments 

 the hair has been found to 

 grow seven lines per month. 

 Frequent shaving greatly 

 increases its growth. It also 

 grows faster by day than 

 by night, and in summer 

 than in winter. 



A small portion of the Follicle of a Hair 

 of the Beard, with the Arteries supplying it— very highly Magnified. 1, Its Follicle. 2, 

 Its Pulp. 3, The Trunk of the Hair without the Follicle. 4, 4, Two Arteries going 

 to the Base of the Follicle. 5, 5, Their Distribution. 6, 6, The Reticulated Tissue of 

 the Follicle. 



FUNCTIONS OF THE SKIN. 



534. The Skill a Covering —The skin is the natural cov- 

 ering of the body of man, and he is not furnished with any 

 further and more complete covering, as is the case with many 

 of the lower animals, since he is endowed with an ability to 

 devise means of covering better suited to his condition than 

 one of hair, wool, or feathers. 



535. Use of the Epidermis— To Protect the Nerves — 

 The epidermis is of use to protect the corium and its vessels. 

 Without this covering many of our sensations acquired through 

 the skin would be very painful. The contact of the softest 

 Eider down with the exposed nervous filaments would impart 

 the acutest pain, and the rays of the noonday sun would in- 

 flict the keenest torture. The body could not endure the 

 lightest clothing, and even our motion through the air would 



533 c. What is said of .the rate of growth of the hnir? 534. What is Paid of the pfcln as 

 a covering ? 535. What is said of the epidermis as a source of protection to the delicate 

 nerves of touch ? 



