528 SUDORIPAROUS GLANDS. 



bulated gland. In some situations, the excretory ducts of these glands 

 open independently on the surface of the epidermis; while in others, and 

 the most numerous, they terminate in the follicles of the hairs. The 

 sebaceous glands associated with the hairs are racemiform and lobulat- 

 ed in structure, consisting of sacculi which open by short pedunculated 

 tubuli into a common excretory 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 constantly associated with small 

 hair-follicles. In the meatus auditorius the sebaceous (ceruminous) 

 glands are also large and lobulated, but the largest are those of the 

 eyelids, the Meibomian glands. The excretory ducts of sebaceous 

 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 epidermis is thick, they 

 assume a spiral arrangement. The sebaceous ducts and glands are 

 lined by an inversion of the epidermis, which forms a thick and funnel- 

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

 Sebaceous 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 entozoon folliculorum. 



The SUDORIPAROUS GLANDS are situated deeply in the integument, 

 namely, in the subcutaneous areolar tissue, where they are surround- 

 ed by adipose cells. They are small, oblong bodies, composed of one 

 or more convoluted tubuli, or of a congeries of globular sacs, which 

 open into a common efferent duct. The latter ascends from the gland 

 through the dermis and epidermis, and terminates on the surface by a 

 funnel-shaped and oblique aperture or pore. The efferent duct pre- 

 sents some variety in its course upwards : thus, below the dermis it is 

 curved and serpentine, and having pierced the dermis, if the epidermis 

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

 times it is spirally curved beneath the dermis, and having passed the 

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

 dermis, the last turn forming an oblique and valvular opening on the 

 surface. The spiral course of the duct is especially remarkable in the 

 thick epidermis 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 intervals of the small, square-shaped 

 clumps of papillae. Indeed the apertures of the pores, seen upon the 

 surface of the epidermic 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 sudori- 



