18 OUTLINES or EQUINE ANATOMY. 



the follicle, and terminates in the apsx. It consists of an 

 external or cortical layer, the cells of which are imbricated 

 (arranged like tiles upon a honse), and a central medul- 

 lary portion, consisting of soft, spheroidal cells. The 

 sebaceous glands pour their secretion into the follicle ; it 

 is an oily substance, and permeates the hair, rendering it 

 pliable. These glands are small fiask-shaped bodies of the 

 racemose class. The sudoriparous glands produce the 

 sudor or sweat, which thej pour out upon the surface of 

 the skin. Each gland consists of a single elongated tube, 

 which is ver J much twisted upon itself in the subcutaneous 

 areolar tissue so as to form a small, rounded mass per- 

 meated by blood-vessels. It takes a slightly wavy course 

 through the dermis, and in passing through the epidermis 

 becomes cork-screw like. Hairs are either short and glossy, 

 as those covering the surface of the body in general, or 

 long and coarse, with their bulbs deeply imbedded in the 

 subcutaneous tissue, forming horsehair, found in the mane, 

 tajl, eyebrows, eyelashes, and tentaculse of the lips, which 

 in the upper lip of some coarse-bred horses become long 

 and wavy like the human mustachois. Fineness and 

 scantiness of hair is a mark of a well-bred horse. It varies 

 in colour in horses from white to black. In the ass it gene- 

 rally assumes a brownish-white mouse colour, and a dark 

 line of hair extending down the back assists in distin- 

 guishing Equus asinus from E. caballus. The modifica- 

 tion which hair undergoes in forming horn will be 

 described in its proper place. 



We must now examine those complex arrangements of 

 mucous membrane which produce glands. All glands are 

 depressions in mucous membrane, and these depressions 

 may assume either the tubular or the follicular form, and 

 either of these may be simple or compound. Simple tubu- 

 lar glands are those which consist of a single undivided 

 tubular depression of mucous membrane : examples are the 

 follicles of Lieberkiihn, and the sudoriparous glands — the 

 former of which are extremely shallow, the latter much 

 elongated. Sometimes these tubes divide at their deep- 

 seated extremities, and each part may again subdivide, and 

 thus, by continuation of this process, compound tubular 

 glands, such as the testes or the kidneys, are produced ; 

 the latter organ has dilated extremities of its tubules, and 

 thus resembles compound follicular glands. 



