CUTANEOUS GLANDULE, 



417 



rhich is destined to free the blood of a large quantity of fluid ; and 

 te other to draw off a considerable amount of solid matter. To effect 

 tese processes, we meet with two distinct classes of glandulse in its 

 ibstance ; the Sudoriparous or sweat-glands ; and the Sebaceous or oil- 

 rlands. They are both formed, however, upon the same simple plan ; 

 id can frequently be distinguished only by the nature of their secreted 

 roduct. 



743. The Sudoriparous or perspiratory glandulae form small oval or 

 globular masses, situated just beneath the cutis, in almost every part of 

 the surface of the body. Each is formed by the convolution of a single 

 tube ; which thence runs towards the surface as the efferent duct, 

 making numerous spiral turns in its passage through the skin, and 

 penetrating the epidermis rather obliquely, so that its orifice is covered 

 by a sort of little valve of scarf-skin, which is lifted up as the fluid 

 issues from it (Fig. 130). The convoluted knot, of which the gland 



Fig. 130. 



The anatomy of the Skin : 1. The Epidermis, showing the oblique laminae of which it is composed, and 

 the imbricated disposition of the ridges upon its surface. 2. The Rete Mucosum, or deep layer of the epi- 

 dermis. 3. Two of the quadrilateral papillary clumps, such as are seen in the palm of the hand or sole of 

 the foot; they are composed of minute conical papillae. 4. The deep layer of the cutis, the Corium. $. Adi- 

 pose cells. 6. A Sudoriparous gland with its spiral duct, such as is seen inf the palm of the hand or sole of 

 the foot. 7. Another Sudoriparous gland with a straighter duct, such as is seen in the scalp. 8. Two 

 hairs from the scalp, enclosed in their follicles ; their relative depth in the skin is preserved. 9. A pair of 

 Sebaceous glands, opening by short ducts into the follicle of the hair. 



consists, is copiqusly supplied with blood-vessels. On the palm of the 

 hand, the sole of the foot, and the extremities of the fingers, the aper- 

 tures of the perspiratory ducts are visible to the naked eye, being situ- 

 ated at regular distances along the little ridges of sensory papillae, and 

 giving to the latter the appearance of being crossed by transverse lines. 

 According to Mr. Erasmus Wilson, as many as 3528 of these glandulse 

 exist in a square inch of surface on the palm of the hand ; and as every 

 tube, when straightened out, is about a quarter of an inch in length, it 

 follows that in a square inch of skin from the palm of the hand, there 

 exists a length of tube equal to 882 inches, or 73J feet. The number 



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