128 SUDORIPAROUS GLANDS. [sect. 70. 



the ordinary ones on the other. If we further consider that, in 

 exceptional cases, the sudoriparous glands in other places, as, e.g., 

 in the areola of the breast, yield a fluid abundant in granules, and 

 that the ordinary sweat also contains fat and nitrogenous substances, 

 we arrive at the conviction, that a separation of the larger glands 

 of the axilla from the ordinary sudoriparous glands, on account of 

 their secretion is not advisable ; and the more so, as we do not as 

 yet by any means know whether the latter may not, under certain 

 circumstances, also contain granules. With regard to the origin 

 of the granular contents, they must be referred to cells which are 

 formed in the gland-tubes. In fact, cells are frequently met with 

 in the latter which contain the same granules as occur free in the 

 canals, and often, so to speak, entirely constitute their contents. 

 It may happen, also, that in one and the same gland the ends of 

 the gland-tubes contain nothing but cells, while the excretory duct 

 contains not a trace of such cells, but only granules and occasional 

 free nuclei; and, in such cases, it is easy to perceive how the cells 

 disappear as they pass upwards, and allow their contained granules 

 and nuclei to become free. These evidently arise from the epi- 

 thelial cells of the tube of the glandular coil ; for, first, the cells of 

 the contents and those- of the epithelium are in all respects alike ; 

 and, secondly, no epithelium is usually to be found in the glands 

 when their secretion abounds in cells and granules, so that the latter 

 comes into immediate contact with the membrana propria. Now 

 — since, on the other hand, the epithelium may always be very 

 clearly seen in those glands which contain only clear fluid, and fre- 

 quently includes many dark, pigmentous (even gold-yellow) granules 

 in its cells — it may be assumed, that the cells found in the contents 

 are really cast-off epithelium, and that the secretion, in general, de- 

 pends upon the continual growth and detachment of epithelial cells. 



§ 70. Sweat-ducts. — The excretory ducts of the sudoriparous 

 glands, the sio eat- ducts, or spiral canals (fig. 56), commence at the 

 uppermost end of the glandular coil as simple canals, ascend 

 with a slightly serpentine course through the cutis, and then enter 

 the epidermis between the papillae, never at their apices. Arrived 

 here, they begin to become twisted, and, according to the thickness 

 of the epidermis, make from two to sixteen narrower or wider spiral 

 windings, till, at last, they open on the free surface of the epidermis 

 with small, round, frequently funnel-shaped openings, the so-called 

 sweat-pores. 



The length of the sweat-ducts depends upon the position of the 



