THE INTEGUMENT. 



65 



change of condition, during which they have powers of attrac- 

 tion, elaboration, and transmission of substances. The active 

 condition of the cells is not, however, proved to be in all 

 instances occasional, and excited only by nervous stimulus. 

 While saliva and gastric juice are poured out in response to 

 occasional nervous irritations, the secretions of the kidneys 

 and skin never wholly cease in health; and it is possible 

 that in these organs the corpuscles have a certain amount of 

 continuous activity, comparable with tonicity in muscles. 



41. The Integument. The integument combines the 

 functions of protection, sensation, and secretion, and consists 

 of two parts, the epidermis and the cutis vera. 



Fig. 37. INTEGUMENT OF HAND, vertical section magnified, a c, 

 epidermis; a 6, horny layer; b c, rete mucosum; c, elongated 

 corpuscles of deepest layer ; d d, capillary blood-vessels in two 

 papillae ; e, nerve fibre, ending in a touch corpuscle ; /, duct of 

 sweat gland, spiral in the horny layer ; g, the same, beneath the 

 integument. 



The epidermis } cuticle, or scarf-skin, is a stratified squamous 

 14 E 



