PROCEEDINGS OF SOCIETIES. 93 
.to consider these lines across the substance of the caudate nerve- 
cells as another remarkable fact in favour of the existence of such 
circuits ; for while the appearance would receive a full and satis- 
factory explanation upon such an hypothesis, 1 doubt if it be 
possible to suggest another explanation which would seem even 
plausible. 
Nor would it, I think, be possible to adduce any arguments 
which would so completely upset the view that nerve-force passes 
centrifugally from one cell, as from a centre, towards its peripheral 
destination, as this fact. So far from the fibres radiating from one 
cell, or from the nucleus as some suppose, in different directions, 
all the fibres which reach the cell are complex, and contain lines 
which pass uninterruptedly through it into other fibres. Instead 
of the cell being the point from which nerve-currents radiate in 
different directions along single fibres, it is the common point 
where a number of circuits having the most different distri- 
bution intersect, cross, or decussate. The so-called cell is a part of 
a circuit, or rather of a great number of different circuits. 
I conclude that at first the formed material of the cell is quite 
soft and almost homogeneous, but that as currents traverse it in 
certain definite lines, difference in texture and composition is pro- 
duced in these lines, and perhaps after a time they become more 
or less separated from one another, and insulated by the interven- 
ing material. 
It may perhaps be carrying speculation upon the meaning of 
minute anatomical facts too far to suggest that a nerve-current 
traversing one of these numerous paths or channels through the 
cell may influence all the lines running more or less parallel 
to it (fig. 3). 
I have ascertained that fibres emanating from different caudate 
nerve-cells situated at a distance from one another (fig. 4, a, a) at 
length meet and run on together as a compound fibre (6, 6, 0), so 
that I am compelled to conclude (and the inference is in harmony 
with facts derived from observations of a different kind), that every 
single nerve-fibre entering into the formation of the trunk of a 
spinal nerve, or single fibre passing from a ganglion, really con- 
sists of several fibres coming from different and probably very 
distant parts. In other words, I am led to suppose that a single 
dark-bordered fibre, or rather its axis-cylinder, is the common 
channel for the passage of many different nerve-currents having 
different destinations. It is common to a portion of a great many 
different circuits. The fibres which result from the subdivision of 
the large fibre which leaves the cell become exceedingly fine (the 
sooloooth of an inch in diameter or less), and pursue a very long 
course before they run parallel with other fibres. As the fibres 
which have the same destination increase in number, the compound 
trunk becomes gradually thicker and more distinct. The several 
individual fibres coalesce and form one trunk, or axis-cylinder, 
around which the protective white substance of Schwann collects. 
At the periphery the subdivision of the dark-bordered fibre 
