464 



OKGAN OP TOUCH. 



ORGAN OF TOUCH. 



The Skin is composed of three layers, viz. the 



Cutis, 



Rete mucosum, 



Cuticle. 



The Cutis (dermis), or true slsin, covers the entire surface of the" 

 body, and is continuous with the mucous membrane which lines its 

 cavities. It consists of two layers, a deep one called corium, and a 

 superficial or papillary layer. 



The Corium is the base of support to the skin, and owes its den- 

 sity of structure to an interlacement of- fibrous bands which form a 

 firm and elastic web. By its under surface it is connected with the 

 common superficial fascia of the body, and presents a number of 

 areolse, in which are lodged small masses of adipose tissue. 



On the upper surface the fibres are more closely aggregated, 

 and form a smooth plane for the support of the papillary layer. 



The corium differs very much 



Fig. 142* i n thickness in different parts of 



the body; thus, on the lips, eye- 

 lids, and scrotum it is extremely 

 thin. On the head, back, soles of 

 the feet, and palms of the hand it 

 is very thick; and on the more 

 exposed parts of the body it is 

 much thicker than on those which 

 are protected. 



The Papillary layer is soft, and 

 formed by minute papillae which 

 cover every part of its surface. 

 On the body generally, the papillse 

 are very small and irregular in 

 their distribution; they are best 

 seen in the palm of the hand or 

 sole of the foot, where they are 

 disposed in linear ridges, as indi- 

 cated by the markings on the 

 cuticle. The ridges of papillse in 



* The anatomy of the skin. 1. The cuticle, showing the oblique laminae of which it 

 is composed and the imbricated disposition of the ridges upon its surface. 2. The rete 

 mucosum. 3. Two of the quadrilateral papillary masses, such as are seen in the 

 palm of the hand or sole of the foot; they are composed of minute conical papillae. 4. 

 The deeper layer of the cutis, the corium. 5. Adipose vesicles ; showing their appear- 

 ance beneath the microscope. 6. A perspiratory gland with its spiral duct, such as is 

 seen in the palm of the hand or sole of the foot. 7. Another perspiratory 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. -> 





