212 



TWENTIETH LECTURE. 



In a preceding lecture (p. 58), we remarked that the human 

 corium developed papilla-like projections, which were some- 

 times higher, sometimes 

 lower. In the volar sur- 

 face of the fingers and 

 toes, the hollow of the 

 hand, and the sole of 

 the foot, and, finally, 

 the heel, we meet with 

 papillae of a double na- 

 ture. One portion con- 

 tains a vascular loop {b) ; 

 others, non-vascular, 

 contain the nerve ter- 

 mination (above, i). 

 The number of these 

 nerve papillae is great- 

 est at the volar surface 

 of the finger point ; 

 from here they con- 

 stantly decrease. The 

 toes are less favored ; 

 but here, also, the same 

 law prevails of the diminu- 

 tion towards the sole of 

 the foot. Without going 

 further into this subject, 

 we merely remark here 

 that only the ape, our 

 nearest corporeal relation, 

 presents tactile bodies. 

 They are wanting in the 

 other mammals. 



A tactile body (Fig. 

 184) is either oval or, 



Fig. 184.— Two human nervous papillse from the ,,,,>1, cmallpr rlimptisinns 



skm of the volar surface of the index finger. In the W1U1 Smaild aimeilSlOIlb, 



interior of the papilla is the tactile body, into the ~r\t\nAc*A Tfc rlinmptpr 



tissue of which the nerve fibres enter. rOUnaea. IIS UlclIIlCLCr 



Fig. 183. — Human skin in perpendicular section; a, 

 superficial layers of the epidermis ; b, Malpighian rete- 

 mucosum. Beneath the latter is the corium, forming the 

 papillae above at c, and terminating below in the subcu- 

 taneous connective tissue, in which at A, aggregations of 

 fat cells appear ; g, sudoriparous glands, with their excre- 

 tory ducts e andy"; ti, vessels ; c, nerves. 



