APPLIED PHYSIOLOGY 



459. Skin grafting. A spot of skin deprived of epithe- 

 lium is tender and sore. New flesh forms over its surface, 

 while the epithelial cells at its edge produce new ones 

 which spread over the whole surface and complete the 

 healing. If they do not grow, the new flesh sprouts above 



the skin, forming 

 proud flesh. 



The deeper cells 

 of the epidermis 

 may remain alive 

 for some hours 

 after being cut off 

 from the body. 

 ft When placed upon 

 a clean ulcer, they 

 6 may grow and 

 e produce a new epi- 

 g thelium. This is 

 skin grafting. 

 ^x-460. Papillae. 

 From the sur- 

 face of the derma 

 small projections 

 about ^0- of an 

 inch in length, 

 called papillcs, ex- 

 tend a short dis- 

 tance into the epidermis. They contain nerves of feeling. 

 The papillae over a small area sometimes become over- 

 grown, so that they project above the skin, forming a 

 wart. Rows of papillae form the fine curved lines upon 

 the balls of the fingers and the palms of the hands. They 

 are most numerous where the sensation of touch is greatest. 



A hair (X 200). 



a epidermis of the skin. 



b hair shaft. 



c sebaceous gland. 



d muscle which makes the hair erect. 



e epidermis of the hair root. 



/ fat cells in the derma. 



g papilla from which the hair grows. 



