1864.] 



of Nerve-currents in Nerve-cells. 



387 



mode of development. In this paper I propose to describe some points of 

 interest in connexion with their structure. In the first place, however, I 

 would remark that there are neither ' cells ' nor ' vesicles ' in the ordinary 

 acceptation of these words, for there is no proper investing membrane, 

 neither are there * cell- contents' as distinguished from the membrane or 

 capsule ; in fact the so-called cell consists of soft solid matter throughout. 

 The nerve-fibres are not prolonged from the nucleus or from the outer part 

 of the cell, but they are continuous with the very material of which the 

 substance of the * cell ' itself is composed, and they are, chemically speaking, 

 of the same nature. So that in these caudate cells we ha;ve but to recos:- 

 nize the so-called 'nucleus' {germinal matter) and matter around this 

 (^formed material) which passes into the 'Jibres,' which diverge in various 

 directions from the cell : see Plate III. (fig. 1). 



At the outer part ©f many of these ' cells,' usually collected together in 

 one mass, are a number of granules. These are not usually seen in the 

 young cells, and they probably result from changes taking place in the 

 matter of which the substance of the cell is composed. But it is not pro- 

 posed to discuss this question in the present paper. 



My special object in this communication is to direct attention to a pecu- 

 liar appearance T have observed in these cells, which enables me to draw 

 some very important inferences with reference to the connexions and action 

 of these very elaborate and most important elements of the nervous 

 mechanism. 



In some very thin sections of the cord and medulla oblongata of a young 

 dog, which had been very slowly acted upon by dilute acetic acid, the ap- 

 pearances represented in Plate III. (fig. 1) were observed. Subsequently, 

 similar appearances, though not so distinct, have been demonstrated in the 

 caudate nerve-vesicles of the grey matter of the brain of the dog and cat, 

 as well as of the human subject. I have no doubt that the arrangement is 

 constant, and examination of my specimens will probably satisfy observers 

 that the appearance is not accidental. Each fibre (a, a, a) passing from 

 the cell exhibits in its substance several lines of granules. The appearance 

 is as if the fibre were composed of several very fine fibres imbedded in a 

 soft transparent matrix, which fibres, by being stretched, had been broken 

 transversely at very short intervals. At the point where each large fibre 

 spreads out to form the body of the cell, these lines diverge from one 

 another and pursue different courses through the very substance of the cell, 

 in front of, and behind, in fact around the nucleus. Lines can be traced 

 from each fibre across the cell into every other fibre which passes away from 

 it. The actual appearance is represented in Plate III. ; and in the diagram, 

 fig. 2, a plan of a 'cell,' showing the course of a few of the most important 

 of these lines which traverse its substance, is given. 



I do not conceive that these lines represent fibres structurally distinct 

 from one another, but I consider the appearance is due to some difference 

 in composition of the material forming the substance of the cell in these 



VOL. XIII. 2 F 



