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. 38. Vertical section of the Frog's skin, highly magnified, (x about 200.) 

 D. derm, formed of hf, hf,' hf." 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, 



