126 



HEALTH AND DISEASE 



Although the cuticle, as has been shown, consists of ditterent layers 

 of cells from the deeper, recently-formed globules, through the oval, and 

 elliptical, to the flattened scales, it constitutes a very small portion of the 

 total thickness of the skin. 



Cutis or Derma. — The cutis, derma, or true skin, is composed of a 

 basis of dense fibrous structure, the fibres of which are closely interwoven 

 one with another. Distributed through the meshes of the fibrous base of 

 the skin are various glands and follicles. In the deeper-seated portions 

 there are small masses of fatty tissue embedded in the fibrous net-work. 

 At the superior part of the true skin exists what is called the papillated 

 layer of the derma, so termed from the small papillae which everywhere 

 stud its surface. It consists of vascular and nervous elements. The blood- 

 vessels here, are arranged in the form of capillary loops; the terminal 

 branches of nerves wind round minute prolongations of tissue in which the 

 sense of touch exists, and which are consequently termed tactile papillae, 

 or tactile corpuscles (fig. 259). 



Glands of the Skin. — The glands of the skin are of two kinds: 

 1, sebaceous or fat-forming; 2, sudori- 

 parous or sweat glands. 



Those from which the sebaceous secre- 

 tion is produced are minute lobulated 

 structures situated in the fibrous tissue 

 of the derma (6, fig. 260). The sebaceous 

 glands are provided with ducts, some of 

 which open on the surface of the cuticle, 

 but by far the greater number pour their 

 secretion into the hair follicles. They 

 are necessarily very numerous in animals 

 which have a hair covering. These 

 glands are always most abundant and 

 of larger size and greater activity in 

 those parts of the skin which are con- 

 stantly subject to movement, as in the 

 bends of joints, and it is extremely probable that at each flexion and 

 extension of a joint a certain amount of sebaceous matter is squeezed 

 out of the ducts, thus keeping the skin in a soft and supple condition. 

 The sudoriparous or sweat glands are situated deeper in the substance 

 of the true skin than those above described. Some of them even pass 

 beyond it into the subcutaneous areolar tissue. These sweat glands are 

 not lobulated as the sebiparous or sebaceous glands are, but consist of 

 one or more long tubes twisted upon themselves so as to form a more 



1, Epidermis. 2, Derma. 3, Areolar Tissue. 

 4, Hair Follicle. 5, Hair. 6, Sebaceous Gland. 

 7, Sudoriparous or Sweat Gland. 7', Duct of 

 Sweat Gland. 7", Opening of Sweat Gland. 



