.114 EXCRETION. 



the papillary layer. The epidermis is also divided into two 

 layers ; an external layer, called the horny layer ; and an in- 

 ternal layer, called the Malpighian, or the mucous layer, 

 which is in contact with the papillary layer of the corium. 



The Cerium, or True Skin. The reticulated and the 

 papillary layer of the true skin are quite distinct. The 

 lower stratum, the reticulated, is much thicker than the 

 papillary layer, is dense, resisting, quite elastic, and slightly 

 contractile. It is composed of numerous bundles of white 

 fibrous tissue interlacing with each other in every direction, 

 generally at acute angles. Distributed throughout this layer 

 are found numerous anastomosing elastic fibres of the small 

 variety, and with them a number of non-striated muscular 

 fibres. This portion of the skin contains, in addition, a con- 

 siderable 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 electrici- 

 ty, the follicles are drawn up, projecting upon the general 

 surface, and producing the appearance known as " goose- 

 flesh." Contraction of these fibres is particularly marked 

 about the nipple, producing 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 at- 

 tached to the surface of the true skin and the base of the 

 follicles, was first described by Kolliker, 1 and explains fully 

 the manner in which the " goose-flesh " is produced. Con- 

 traction of the skin, in obedience to the stimulus of electrici- 

 ty, has been demonstrated by Froriep, Brown-Sequard, and 

 Kolliker, both in the living subject and in executed criminals 

 immediately after death. 3 



1 KOLLIKER, Handbuch der Gewebelelire des Memclien, Leipzig, 1867, S. 98. 

 8 KOLLIKER, Manual of Human Microscopic Anatomy, London, 1860, p. 86. 



