-ANATOMY OF THE SKIN. 115 



The papillary layer of the skin passes insensibly into 

 the subjacent structure and presents no well-marked line 

 of division. It is composed chiefly of the same kind of 

 amorphous matter that exists in the reticulated layer. 

 The papillae themselves appear to be simply elevations 

 of this amorphous matter, though they may contain a few 

 fibres. In this layer we find a number of fibro-plastic 

 nuclei with a few little corpuscular bodies called by Kobin, 

 cytoblastions. 1 



As regards their form, the papillae may be divided into 

 two varieties ; the simple and the compound. The simple 

 papillae are conical, rounded, or club-shaped elevations of the 

 amorphous matter, and are irregularly distributed on the 

 general surface. The smallest are from -^ to ^^j- of an 

 inch in length, and are found chiefly upon the face. The 

 largest are on the palms of the hands, the soles of the feet, 

 and the nipple. These measure from -^j- to -^-5- of an inch. 

 Large papillae, regularly arranged in a longitudinal direction, 

 are found beneath the nails. The regular, curved lines 

 observed upon the palms of the hands and the soles of the 

 feet, particularly the palmar surfaces of the last phalanges, 

 are formed by double rows of compound papillae, which pre- 

 sent two, three, or four points attached to a single base. In 

 the centre of each of these double rows of papillae is an ex- 

 cessively fine and shallow groove, in which are found the ori- 

 fices of the sudoriferous ducts. 



The papillae are abundantly supplied with blood-vessels, 

 terminating in looped capillary plexuses, and nerves. The 

 termination of the nerves is peculiar, and will be fully de- 

 scribed in connection with the organs of touch. The ar- 

 rangement of the lymphatics, which are very numerous in 

 the skin, has already been indicated in the general descrip- 

 tion of the lymphatic system. 3 



1 LITTRE ET ROBIN, Dictionnaire de medecine, Paris, 1865, Article, Cyto- 

 blastion. 



8 See vol. ii., Absorption, p. 430. 



