CHAP, vm 



SKIN 



127 



yourself, the directions given on pp. 136 139 are 

 simple enough to be carried out with very limited 

 appliances. 



The Skin. A vertical section of the skin, i.e., one 



FIG. .18. Vertical section of the Frog's skin, highly magnified. ( - about 200.) 

 D. derm, formed of hf, tif,' fif." horizontal, and v. f. vertical fibres of connective, 

 tissue, and containing b. v. blood-vessels, and pg. pigment cells. E. epiderm, 

 with m. /. active or Malpighian layer, and H. /. horny layer of epithelial 

 cells ; c. gl. cutaneous gland in section ; c. gl'. in surface view ; d. duct. (After 

 Howes.) 



taken at right angles to its surface, will be seen to have 

 the following structure. 



The skin is clearly divisible into two layers, an outer, 



