172 STRUCTURE OF THE NERVOUS SYSTEM, BY MAX SCHULTZE. 



In regard to the mode of termination of the nerves in glands, 

 the investigations of Pfliiger* on the salivary glands may here 

 be mentioned, in which he showed that the extremities of the 

 nerves formed such a connection with gland cells, that either the 

 cells themselves or their nuclei constituted the terminal organ, 

 as will be more explicitly described in the article on GLANDS. 



Hensen has described the cutaneous nerves of the frog as 

 terminating peripherically in the nucleoli of the cells of the 

 epidermis.^- They form extraordinarily fine fibres, which 

 penetrate both the cells and nuclei, and in consequence of the 

 frequent division of the nuclei are also themselves frequently 

 bifurcated. 



3. ON THE MODE OF ORIGIN OF THE NERVE FIBRES IN THE 

 NERVE CENTRES. 



The transition from the foregoing to the consideration 

 of the central source or origin of the nerve fibres is to be 

 found in the description of those nerve or ganglion cells 

 which are intercalated in the course of the nerve fibres, 

 and of the so-called ganglia. The microscopic examina- 

 tion of the ganglia of the brain and spinal cord, as well 

 as of the sympathetic nerves, alike shows that the cells 

 are to be regarded as an essential part of these structures, 

 and that they exhibit a nucleus and nucleoli lying in a rela- 

 tively considerable quantity of a dense finely granular and 

 fibrillated cell substance, which is often tinged of a yellow 

 colour. The greater number of these cells, when isolated in 

 the perfectly fresh state in serum, are spheroidal ; yet they are 

 often also very irregular in outline, destitute of any doubly con- 

 toured investing membrane, and become broken up and dis- 

 appear with the greatest facility. In sections made through 

 fresh or hardened ganglia such cells appear to be arranged in 

 layers surrounded by fibrous connective tissue, in which large 

 numbers of both medullated and non-medullated nerve fibres 



* Die Endigungen der Absonderungsnerven in die Speicheldrusen. Bonn., 

 1866. 



t Virchow's Archiv, Band xxxi., p. 63, Taf. 2, fig. 14 ; Archiv fur 

 Mikroskopische Anatomie, Bandiv., p. 121. 



