512 ANATOMICAL TECHNOLOGY. 



just named, requiring a special apparatus, there is the. 'so called 

 general sensibility of the body. This is manifested whenever an 

 ordinary sensory nerve is stimulated in any part of its course ; 

 when slight, it is called feeling ; when more intense, pain. 



CUTIS— THE SKIN. 



References.— Gray, A, 83 ; Quain, A, II, 311 ; Dalton, A, 510 ; Foster and Langley, 

 A, 165 ; Foster, A, 589 ; Leyh, A, 350 ; Strieker, A, 793 ; Chauveau, A, 841 ; Chauveau 

 (Fleming), A, 793 ; Owen, A, III, 186, 610 ; Gurlt, A, 815 ; Milne-Edwards, A, XI, 411 ; 

 Bernstein, A, 10 ; Flint, A, 381, 751. 



§ 1395. Cutis, skin. — The skin or integument forms the covering 

 of the entire body. It is elastic and flexible, tough and dense, 

 hence well adapted as a protecting envelope. It is continuous 

 with the mucous membranes at the various natural orifices. 



§ 1396. The skin is composed of two layers, octal and ental. 



Ectal Layer, Spidermis, Guticle. — Composed of nucleated cells, those nearest the sur- 

 face are flat ; the deeper ones are spherical or columnar and form the Bete mucosum, 

 which contains the coloring matter of the skin. 



The function of the epidermis is almost wholly protective, and it is devoid of sensi- 

 bility. 



Bntal Layer, Derma, Corium, Cutis vera (true skin). — The true skin is composed of 

 elastic and white connective tissue, plain muscles, blood vessels, lymphatics and nerves. 

 The principal function of the Cutis vera is tactile sensibility or the determination of the 

 presence and character of objects which come in contact with the epidermis. 



Into it are implanted the appendages of the skin — hair and daws, sweat and seiaceoua 

 glands. 



The sweat glands serve to get rid of some of the waste products of the body, while the 

 sebaceous glands pour out upon the surface an oily substance which keeps it soft and 

 pliable. 



The hair and claws serve as protectors of the body. The hair covers the entire surface 

 of the body except at the tip of the snout, the pads of tlie hands and feet and the hypoth- 

 enar eminences. It protects the surface and assists more or less in touch, since a nervous 

 filament is connected with the implanted end of each hair. In addition to the ordinary 

 hairs forming the protective covering of the body, there are specialized hairs which, from 

 their connections, are undoubtedly tactile organs. These are situated, in the cat, on the 

 dorsal lip (Vibrissae, Fig. 87, 88), in the eyebrows (Fig. 87, 88), and on the antebrachium 

 (Fig. 76, 105, pili tactiles). They differ from common hairs in being longer and stiffer, 

 but especially in being implanted very deeply and in having a larger nervous and vascu- 

 lar supply. 



For the structure and presence of tactile hairs in various animals, see Owen, A, III, 

 187 ; Curtis, L., 1, 166; Schoebl, 10 ; Ranvier, A, 913 ; Milne-Edwards, A, XI, 434. For 

 the structure of the skin of the dog, see Stirling, 1, 465. 



LINGUA— THE TONGUE. 



References.— Gray, A, 707 ; Quain, A, II, 335 ; Dalton, A, 463, 613 ; Foster and 

 Langley, A, 176 ; Foster, A, 586 ; Leyh, A, 849 ; Strieker, A, 353 ; Chauveau, A, 355, 



