NERVES. 373 



nervous matter composing the two or three systems into 

 which, in the present day, it is divided, presents all the 

 essential and distinctive characters of a true gland, so that its 

 description would have been more correctly given under the 

 general heading of " Glands." 



The nerve or ganglionary cells present essentially the same 

 structure as all other glandular cells, and are doubtless con- 

 tinually passing through the same phases of development and 

 destruction during the progress of nutrition and secretion. 



The secreting or glandular cells in the brain and spinal 

 marrow, are for the most part aggregated into distinct 

 masses, the term ganglia being equally applicable to these 

 masses as it is to those existing in connexion with the 

 nerves of the sympathetic system. Henle considers that the 

 principal development of new cells takes place on the outer 

 surface of the brain, which is the most vascular from its con- 

 tiguity to the pia mater, and that the more mature cells are 

 gradually conveyed inwards, coming thus into nearer con- 

 nexion with the tubular or conducting fibres, the disin- 

 tegration and removal of the older cells determining the 

 movement of the cells from without inwards. This view, as 

 applied to the grey matter of the convolutions of the brain 

 is probably correct, and is to some extent confirmed by an 

 observation which I made several months since, viz. that the 

 cortical substance of the cerebellum consists of two distinct 

 portions separated by a well-defined line, perceptible with a 

 common magnifying glass : the outer portion is made up of a 

 granular base, containing but few fully developed cells, while 

 the inner portion consists almost entirely of completely formed 

 cells. The distinct separation of the cortical or secreting 

 matter of the cerebellum into two portions is very remarkable, 

 and the purpose fulfilled by such an arrangement wholly 

 obscure. 



Regeneration of Nervous Matter. The regeneration of the 

 primitive nerve tube admits of proof, both by experiment 

 and direct observation. The experimental proof consists in 

 the simple division of nerves, and even in the removal of 

 portions of them : the parts to which the nerve is distributed, 



