474 SUDORIPAROUS GLANDS. 



The colour of the hair, like that of the epiderma, is due to the colora 

 tion of the primitive granules of the cells. 



The SEBIPAROUS GLANDS are sacculated glandular organs embedded in 

 the substance of the derma, and presenting every variety of complexity, 

 from the simplest pouch-like follicle to the sacculated and lobulated gland. 

 In some situations, the excretory ducts of these glands open independently 

 on the surface of the epiderma ; while in others, and the most numerous, 

 they terminate in the follicles of the hairs. The sebiparous glands asso- 

 ciated with the hairs are racemiform and lobulated in structure, consisting 

 of sacculi which open by short pedunculated tubuli into a common excre- 

 tory duct, and the latter, after a short course, terminates in the hair-follicle. 

 In the scalp there are two of these glands to each hair-follicle. On the 

 nose and face the glands are of large size, distinctly lobulated, and con- 

 stantly associated with small hair-follicles. In the meatus auditorius the 

 sebiparous (ceruminous) glands are also large and lobulated, but the 

 largest are those of the eyelids, the Meibomian glands. The excretory 

 ducts of sebiparous glands offer some diversity in different parts of the 

 body: thus, in many situations they are short and straight, while in others, 

 as in the palms of the hands and soles of the feet, where the epiderma is 

 thick, they assume a spiral arrangement. The sebiferous ducts are lined 

 by an inversion of the epiderma, which forms a thick and funnel-shaped 

 cone at its commencement, but soon becomes uniform and soft. Sebi- 

 parous glands are met with in all parts of the body, but are most abundant 

 in the skin of the face, and in those situations which are naturally exposed 

 to the influence of friction. 



The sebaceous substance, when it collects in inordinate quantities within 

 the excretory ducts, becomes the habitat of a very remarkable parasitic 

 animal, the steatozoon folliculorum. 



The SUDORIPAROUS GLANDS are situated deeply in the corium and also 

 in the subcutaneous areolar tissue, where they are surrounded by adipose 

 cells. They are small, oblong bodies, composed of one or more convo- 

 luted tubuli, or of a congeries of globular sacs, which open into a common 

 efferent duct. The latter ascends from the gland through the derma and 

 epiderma, and terminates on the surface by a funnel-shaped and oblique 

 aperture or pore. The efferent duct presents some variety in its course 

 upwards ; thus within the derma it is curved and serpentine, and if the 

 epiderma be thin, it proceeds more or less directly to the excreting pore. 

 Sometimes it is spirally curved within the derma, and having passed the 

 latter, is regularly and beautifully spiral in its passage through the epi- 

 derma, the last turn forming an oblique and valvular opening on the sur- 

 face. The spiral course of the duct is especially remarkable in the thick 

 epiderma of the palm of the hand and sole of the foot. On those parts of 

 the skin where the papillae are irregularly distributed, the efferent ducts of 

 the sudoriparous glands open on the surface also irregularly, while on the 

 palmar and plantar surfaces of the hands and feet, the pores are situated at 

 regular distances along the ridges, at points corresponding with the inter- 

 vals of the small, square-shaped, clumps of papillae. Indeed, the aper- 

 tures of the pores, seen upon the surface of the epidermal ridges, give rise 

 to the appearance of small transverse furrows, which intersect the ridges 

 from point to point. 



The efferent duct and the component sacs and tubuli of the sudoriparous 

 giund are lined by an inflection of the epiderma. This inflection is thick 



