PHYSIOLOGICAL ANATOMY OF THE SKIN 307 



reticulated layer is much thicker than the papillary layer and is 

 dense, resisting, quite elastic and slightly contractile. It is composed 

 of bundles of fibrous tissue, interlacing with each other in every direc- 

 tion, usually at acute angles. Distributed throughout this layer are 

 found anastomosing elastic fibres of the small variety, and with them a 

 number of non-striated muscular fibres. This layer contains in addition 

 a considerable quantity of amorphous matter, which serves to hold the 

 fibres together. The muscular fibres are particularly abundant about 

 the hair-follicles and the sebaceous glands connected with them, and 

 their arrangement is such that when they are excited to contraction by 

 cold or by electricity, the follicles are drawn up, projecting on the 

 general surface and producing the appearance known as "goose-flesh." 

 Contraction of these fibres is especially marked about the nipple, pro- 

 ducing the so-called erection of this organ, and about the scrotum and 

 penis, wrinkling the skin of these parts. The peculiar arrangement of 

 the little muscles around the hair-follicles, forming little bands attached 

 to the surface of the true skin and the base of the follicles, explains 

 fully the manner in which the "goose-flesh" is produced (see Fig. . 

 67, page 312). 



The papillary layer of the skin passes insensibly into the subjacent 

 structure without any marked line of division. It is composed chiefly 

 of amorphous matter like that which exists in the reticulated layer. The 

 papillae themselves appear to be simple elevations of this amorphous 

 matter, although they contain a few fibres and connective-tissue nuclei. 



As regards 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 dis- 

 tributed on the general surface. The smallest are y^ to ^-J-^ of an inch 

 (36 to 62/4) in length and are found chiefly on the face. The largest 

 are on the palms of the hands, the soles of the feet and the nipple. 

 These measure ^io" to giro of an inch ( IO to I2 5/ x )- Large papillae, 

 regularly arranged in a longitudinal direction, are found beneath the 

 nails. The regular curved lines observed on 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 

 present two, three or four elevations attached to a single base. In the 

 centre of each of these double rows of papillae, is a fine and shallow 

 groove, in which are found the orifices of the sudoriferous ducts. 



The papillae are abundantly supplied with bloodvessels terminating 

 in looped capillary plexuses and with nerves. The termination of the 

 nerves is peculiar and will be fully described in connection with the 

 organs of touch. The arrangement of the lymphatics, which are very 



