THE SKIN AND ITS FUNCTIONS. 



337 



corpuscle (Fig. 229). The nature of this body is obscure. Some regard it 

 as little else than a mass of fibrous or connective tissue, surrounded by 

 elastic fibres, and formed, according to Huxley, by an increased develop- 

 ment of th6 primitive sheaths of the nerve-fibres, entering the papillae. 

 Others, however, believe that, instead of thus consisting of a homogeneous 

 mass of connective tissue, they are special and peculiar bodies of lami- 

 nated structure, directly concerned in the sense of touch. They do not 

 occur in all the papilla? of the parts where they are found, and, as a rule, 

 in the papillae in which they are present there are no blood- vessels. Since 



FIG. 229. Papillae from the skin of the hand, freed from the cuticle and exhibiting tactile cor- 

 puscles. A. Simple papilla with four nerve-fibres: a, tactile corpuscles: 6, nerves. B. Papilla treated 

 with acetic acid; a, cortical layer with cells and fine elastic filaments; ft, tactile corpuscle with trans- 

 verse nuclei; c, entering nerve with neurilemma or perineurium ; d, nerve-fibres winding round the 

 corpuscle, c. Papilla viewed from above so as to appear as a cross-section: a, cortical layer; 6, nerve- 

 fibre; c, sheath of the tactile corpuscle containing nuclei; d, core. X 350. (Kolliker.) 



these peculiar bodies in which the nerve-fibres end are only met with in 

 the papillae of highly sensitive parts, it may be inferred that they are 

 specially concerned in the sense of touch, yet their absence from the 

 papillae of other tactile parts shows that they are not essential to this 

 sense. 



Closely allied in structure to the touch-corpuscles, are some little bodies 

 called end-lulls, about -g-J-g- inch in diameter (Krause). They are gener- 

 ally oval or spheroidal, and composed externally of a coat of connective 

 tissue enclosing a softer matter, in which the extremity of a nerve termi- 

 nates. These bodies have been found chiefly in the lips, tongue, palate, 

 and the skin of the glans penis (Fig. 230). 



Glands of the Skin. The skin possesses glands of two kinds: (a) 

 Sudoriferous, or Sweat Glands; (b) Sebaceous Glands. 



(a) Sudoriferous, or Sweat Glands. Each of these glands consists of a 

 small lobular mass, formed of a coil of tubular gland-duct, surrounded 

 by blood-vessels and embedded in the subcutaneous adipose tissue (Fig. 

 228, c.). From this mass, the duct ascends, for a short distance, in a 

 spiral manner through the deeper part of the cutis, then passing straight, 

 VOL. I. 22. 



