70 



THE SKIN. 



different parts of the bodies of animals; the saccular, or 

 sebaceous glands. 



The tubular, or sweat-glands, consist in fine tubes coiled 

 singly into bulbs of a reddish colour, which is due to their 

 vascularity, and lodged in the deeper part of the skin. From 

 the deep coil the tube passes up to the cuticle, through the 

 cells of which the secretion is forced, and a passage is made 

 which appears twisted like a corkscrew in some animals, and 

 in others, as in the dog, the opening is funnel-shaped. 



Fig. 167. 



Fig. 168. 



Fig. 169. 



Fig. 167. (GTJRLT.) Section of sheep's skin, a, Epidermis; &, True skin; d, Bulb 

 of wool ; e, Stem of wool ; /, Hair-follicle ; g, Oil-glands ; h, Sweat-glands ; i i, Their 

 ducts. 



Fig. 168. (GtJRi/r.) Skin of dog showing the hair-follicles and hairs, a, The oil- 

 glands ; b, The ovoid and elongated sweat-glands, c, with their funnel-shaped openings, 

 d, at the surface. 



Fig. 169. (ERCOLANI. ) Sweat-glands of the ox, showing the simplicity of their forms. 



In some animals each sweat-gland is a tube but slightly 

 coiled, and more open than in the typical form just men- 



