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MANUAL OF HISTOLOGY. 



extended arms, or the remaining branches of a leafless trunk (p). 

 Near this point is suspended the coil of a sweat-gland (e\ held 

 in place by a few delicate fibres which find their insertion at 

 the top of the canal or cleft. The duct of the gland runs to the 

 top of this space, whence it may be traced to the side of the 

 hair-follicle, whence it finds its way to the surface. (In dogs 

 the sweat-duct opens directly into the follicle, a short distance 

 from its mouth.) The fibres of the cutis appear, in vertical sec- 

 tions, to terminate abruptly at its edges. There does not ap- 

 pear to be any structure resembling a " limiting membrane." 

 At its base there is sometimes a slight widening of the cleft, 

 and on the side toward which its axis leans, the fibres of the 

 cutis collect to form a bundle which penetrates the subcutane- 

 ous fat (Cone fibreux de la 

 peau #, Fig. 179). The upper 

 extremity is rounded off in 

 somewhat dome-shape. 



The erector pili muscle, tak- 

 ing its origin from the papillary 

 layer of the cutis, is inserted 

 partly into the base of the fol- 

 licle, which its fibres embrace, 

 and partly into the apex of the 

 fat-canal ; in some sections the 

 fibres seem to penetrate this 

 space, but probably surround 

 it, although some of them may 

 be attached to those delicate 

 bands of fibrous tissue which traverse the column of fat-cells. 

 The muscle lies on the side corresponding with the inclination 

 of the hair externally, and appears almost continuous in its 

 direction with the fat-column beneath it. 



The sebaceous gland lies between the muscle and the follicle 

 at the apex of the angle made by them ; a lobe is found also 

 on the opposite side. 



The number of these columns corresponds to the number of 

 hairs, as they are not found elsewhere. In some sections of 

 skin, half an inch in length, as many as five may be counted ; 

 they are seen to best advantage in the thickest portions of the 

 skin, but may be found on the shoulders and arms, breast, ab- 

 domen, and lower extremities. At some points they appear 



FiO. 180. Section of skin from the shoulder of 

 an infant, magnified seventeen diameters : a, epi- 

 dermis ; &, erector pili muscle ; c, sebaceous gland ; 

 d, fat-column ; e, sudoriparous gland ; g, adipose 

 tissue ; h, hair. 



