262 



THE HUMAN SKIN : 



area for secretion, without increasing the total superficial area of 

 the body. 



Fig. 66 — Simple Gland ; a, Duct or Lumen; other letters as in Fig. i. 



In vertical sections, we see these glands as tubes, cut at various 

 angles in their twisted course, with their ducts, or tubes of exit for 

 the secretion, passing up to the surface. The openings of these 

 ducts form the so-called pores of the skin, at which the beads, or 

 drops of sweat, are poured out. This marvellous economy of 

 space, by such simple means, is but one of the innumerable won- 

 ders with which the human body abounds ; wonders which make 

 the study of anatomy and physiology so full of fascination and 

 instruction to the earnest student of nature. 



P"lG. 67 — Simple convoluted gland, .^^howing tube cut across at 

 various angles. 



