THE SKIN. 



575 



numerous around the sudoriparous glands of the axillae, where 

 they form an almost continuous layer, which expands into a flat, 

 sheet-like arrangement. 



The diameter of the duct, at its beginning, does not exceed 

 that of the tubule within the coil; very soon, however, it becomes 

 decidedly broader, and shows a single stratum of columnar epi- 

 thelia (not stratified, as some authors claim) and a wide caliber. 

 These conditions are particularly marked in cross sections of the 

 duct, such as are often seen in the derma. Delicate bundles of 

 connective tissue, arranged longitudinally, accompany the duct ; 

 no smooth muscle-fibers are present in them. The duct leads in 

 a slightly devious course to a depression between two papillae, 

 and in this situation is composed of stratified epithelia, a forma- 





FIG. 241. COIL OF THE SWEAT-GLAND. 



S, tubule lined by cuboidal epithelia ; T, central caliber of the tubule ; D, beginning of the 

 duct; C, connective tissue with injected blood-vessels. Magnified 500 diameters. 



tion of the rete mucosum, prolonged to a varying depth of the 

 duct. After having reached the epidermal layer, the duct is 

 lined by a single layer of flat epithelia, its caliber being consider- 

 ably widened, especially at its orifice at the surface of the skin. 

 Within the epidermal stratum the duct shows windings which 

 are scarcely perceptible in places where the epidermis is thin, 

 while in situations where the epidermis is very thick, such as 

 the palms of the hands and the soles of the feet, these spiral 



