THE FUNCTIONS OF THE NERVOUS SYSTEM. 263 



fasciculi. These divide again, and cross and intersect each other at various 

 angles. Then the divided fasciculi become again united, and as at first they 

 divided into smaller and smaller fibres ; so when they begin to unite they form 

 gradually larger and larger bundles. At last the nerve which entered a gan- 

 glion emerges from it with its fibres collected into one or more fasciculi. Some- 

 times several nerves enter a ganglion, in which case they are all blended to- 

 gether, forming a complicated net-work, in which it is impossible to determine 

 what belongs to one nerve and what belongs to another nerve. Every fasci- 

 culus or filament which enters a ganglion passes through it. There is no ap- 

 pearance of any one terminating in it." 



"If we unravel the texture of a ganglion, we find that each nervous fibre 

 retains its own peculiar neurilema ; but besides this, the spaces left between the 

 intersection of the fibres are filled up with a peculiar soft substance of a grayish 

 or yellowish colour. With the nature of this substance we are unacquainted. 

 Some have considered it as corresponding to the cineritious substance of the 

 brain and spinal marrow; but Scarpa is disposed to regard it as a soft cellular 

 substance, filled with a grayish and mucilaginous matter in emaciated sub- 

 jects, and with a yellowish oily matter in those that are fat." 



Such then is the structure of the ganglions as far as it is known ; and as, for 

 the reason just mentioned, I shall confine the term to those ganglions which 

 receive nerves proceeding from different parts of the nervous system ; the 

 term ganglionic nerve I shall confine to those nerves which either enter or 

 proceed from such ganglions, without adverting to their having or not having 

 protuberances resembling ganglions belonging to themselves ; although it is 

 probable that a more perfect knowledge of the nervous system will point out 

 this circumstance as a proper basis for a subdivision. It is necessary to keep 

 this explanation in view, because neither the term ganglion nor ganglionic 

 nerve has been employed with much precision. 



Physiology has been greatly indebted to Mr. Bell for his important dis- 

 covery of the different properties of the two sets of nerves which unite in form- 

 ing each of the spinal nerves. It appears from his experiments, which have 

 been confirmed by those of Majendie, that the one set are nerves of sensation, 

 the other of motion ; a circumstance which explains many of the phenomena 

 of disease, which have suggested the probability of these functions being 



