Chap. XXXIV.] 



THE SKIN. 



277 



a continuation from the middle layer of the stratum 

 Malpighii and from the basement membrane ; the 

 former is the lining epithelium, the latter the limiting 

 membrana propria of the sudoriferous canal. The 

 epithelium consists of two or three layers of small 

 polyhedral cells, each with a spherical or oval nucleus. 



Fig. 146. From a Section through Human Skin, showing the Sweat 

 gland tubes cut in various directions. 



a, First part of the coiled tube seen in longitudinal section : 6, the same seen in 

 cross section , c, the distal part seen in longitudinal section ; d, the same seen 

 in cross section. (Atlas.) 



375. The structure of the sudoriferous canal is 

 then a limiting membrana propria, an epithelium 

 composed of two or three layers of polyhedral cells, an 

 internal delicate membrane, and, finally, the central 

 .cavity, or lumen. 



The first part about one-third or one-fourth 

 of the coiled tube (Fig. 146) is of ;the same struc- 

 ture, and is directly continuous with the sudoriferous 

 canal, with which it is identical, not only in structure, 

 but in size. The remainder of the coiled tube i.e., 

 the distal part is larger in diameter, and differs in 



