118 



SPECIAL HISTOLOGY. 



injecting them with quicksilver. All agree in this, that they 

 form an excessively close network of fine vessels in its outer- 

 most part, — according to Krause (1. a, p. Ill) of ^ — ~" in 

 diameter ; the meshes of which become wider internally, and 

 finally open by single trunks into the vessels of the subcuta- 

 neous cellular tissue. However, it is not by any means known, 

 whether the vessels composing these plexuses are really the true 

 commencement of the cutaneous lymphatics. 



§ 37. 

 Nerves. — The skin, in those parts of it which border upon 

 the epidermis, particularly in some localities, is one of the 

 structures most richly provided with nerves in the human 

 organism, whilst in its deeper parts it is remarkable for their 

 scantiness. In the panniculus adiposus, and in the fascia super- 

 ficialis, as yet, no nerves are known besides those, which giving 

 off a succession of branches, traverse those parts to reach the co- 

 rium, or to supply the hair-glands, smooth muscles, and Pacinian 

 corpuscles, of which we shall speak further on. In the corium itself, 

 the trunks which enter through the meshes of the deeper layers 



ascend by degrees, con- 

 n tinually ramifying, but 



without actually forming, 

 terminal expansions, to- 

 wards the pars papillaris. 

 Here they anastomose 

 frequently, and form rich 

 terminal plexuses, in 

 which deeper and more 

 superficial portions may 

 , / be clearly distinguished, 



h ' I; . .V.,, !' i ■ 



P the former consisting of 



fine branches still con- 

 taining many primitive tubules, with wide meshes ; the second 

 of fibres single or united in pairs, with narrow meshes. 

 In this last or the fine terminal plexus, there also occur 



Fig. 54. Two papilla from the extremities of the fingers, without epithelium and 

 with axile corpuscles, a, and nerves, b. A. Simple papula, with four nerve-fibres 

 and two terminal loops, c. B. Compound papilla, with two vascular points witli 

 capillary loops, d ; and one nervous point with a terminal loop, e. 



Fig. 54. 



