204 



SPECIAL HISTOLOGY. 



Fig. SO. 



have hitherto found neither in the sweat of man nor in the smaller 

 glands ; but I may remark that almost constantly, even in the smaller 

 sudoriparous glands, certain canals exist which present no cavity, but 

 are wholly filled with epithelial cells. These appeared to me always 

 to be near the blind end (Fig. 79, B\ whilst those which are nearer the 

 excretory duct, almost invariably exhibit a cavity 0-004-0-1 of a line 

 in diameter. I consider it therefore to be not impossible, that in the 

 common sudoriparous glands, a cellular secretion is at times formed and 

 excreted in the same manner as in the axillary glands ; for from what 

 we see in the canals of the latter, it can hardly be doubted that granules, 

 nuclei, and perhaps also remains of cells, occur in the sweat of the 

 axilla. Whether the sweat in different individuals and races of men 

 present notable differences is unknown, for it is not ascertained that 

 the different odor of the cutaneous exhalation in the European and the 

 Negro, for instance, depends on the sweat or the material of the per- 

 spiration ; nor have its pathological relations been investigated, at all 

 events not microscopically. 



69. Sweat-Ducts. The excretory ducts of the sudoriparous glands, 

 the sweat-ducts, or spiral canals (Figs. 45, 80), commence at the upper 



end of the glandular coil as simple 

 canals, ascend with slight undulations 

 vertically through the corium, and then 

 penetrate between the papillce (never 

 through their points), into the epider- 

 mis. Here they begin to twist, and 

 according to the thickness of the cuticle 

 they perform from 216 closer, or 

 more distant spiral turns, until even- 

 tually they terminate by small, round, 

 often funnel-shaped apertures, the so- 

 called siveat-ytores on the free surface 

 of the epidermis. 



The length of the sweat-ducts de- 

 pends on the situation of the glands 

 and the thickness of the skin. The 

 commencement of the duct is invaria- 

 bly narrower than the canal in the 

 coil itself, measuring 0-009-0-012 of 

 a line ; it continues narrow up to its 

 entrance into the stratum Malpighii 



FiG. 80. Perpendicular section through the epidermis and outer surface of the corium of 

 the bulb of the thumb, transversely through two ridges, treated with acetic acid; , horny 

 layer of the epidermis; 6, mucous layer; c, cutis ; rf, simple papilla; e, compound papilla; /, 

 epithelium of a sweat-duct passing into the mucous layer; g, cavity of it in the cutis; A, in 

 the horny layer ; t, sweat-pore. Magnified 00 diameters. 



