672 June 18, 



than can be effected in sections prepared oy other processes of inves- 

 tigation which I have tried. In many instances one thick fibre is 

 continuous with one or other extremity of the "cell," while from 

 its opposite portion from three to six or eight thinner fibres diverge 

 in a direction onwards and outwards. This arrangement is particu- 

 larly distinct in the grey matter of the sheep's brain. The broad 

 extremities of the cells for the most part are directed towards the 

 white matter of the hemisphere. The cells have no cell-wall ; and 

 the matter of which the fibre is composed is continuous with that of 

 which the outer part of the " cell" consists. 



The so-called "granular matter," or "granular matrix," which is 

 described as existing in considerable quantity in the grey matter 

 around the cells and between the fibres, results, I think from the 

 disintegration of the finest nerve-fibres and cells ; for in the speci- 

 mens I have prepared, the tissue intervening between the cells is 

 seen to be composed entirely of nerve-fibres. The majority of these 

 fibres are not more than the YoTTolTo^ 1 ^ an mc ^ m diameter ; 

 and many fibres, whose continuity with cells can be demonstrated, 

 are as fine as this at a distance of not more than ^ ^ Q Q th of an inch 

 from their origin. The slightest displacement of the thin glass 

 covering the specimen will often destroy these delicate fibres, and 

 nothing but amorphous granular matter results. The apparently 

 free nuclei in the more superficial part of the grey matter are really 

 the nuclei of cells, with every one of which fibres are in connexion. 

 There -are no cells with less than two fibres in continuity with them. 

 In the brain of a young animal it is easy to find many cells connected 

 together by broad bands of fibres, which vary much in length and 

 thickness ; but in the adult a positive connexion between two con- 

 tiguous cells can be demonstrated only here and there. As the cells 

 separate further and further from each other, the fibre becomes so 

 thin and long, and it changes the plane in which it ramifies to such 

 an extent, that it cannot often be traced for any great distance. 



The fibres are formed as the cells, originally continuous, become 

 separated further and further from each other. In all parts of the 

 nervous system the so-called "cells" (often termed "nuclei" in 

 peripheral parts) are structurally continuous with each other through 

 the fibres. 



