26 CiACCio^ on the Distribution of 
If, therefore, the vascular nerve- fibres,, according to our pre- 
sent knowledge, must be regarded as ganglionic, it is evident 
that the fine nerve-fibres in the sheath of the dark-bordered 
fibres perfectly resembling them must also be looked upon as 
fibres of the same nature. 
But if by every appearance we are led to consider the fine 
nerve-fibres in question as ganglionic, from what ganglia may 
they derive their origin ? In answering this second question, 
it is necessary at first to remark, that in the skin of the frog 
I have never succeeded in finding any of those very small 
ganglia which have been observed by Dr. Beale in the bladder 
of the same animal. Their origin must, therefore, be looked 
for elsewhere. It is well-known that in connection with the 
posterior root of each spinal nerve is found a ganglion com- 
posed of numerous ganglionic cells. These cells, according 
to many observers, are connected with one or two, or very 
rarely with several nerve-fibres. But Dr. Beale^s recent and 
very accurate observations^ have shown that this opinion is 
incorrect, for all ganglion-cells are bipolar or multipolar. 
Among the cerebral nerves the fifth nerve very nearly resem- 
bles the spinal nerves. It has, like them, two roots — one 
large is gangliated and sensitive, the other ganglionless is 
motor. It is true that some anatomists have endeavoured to 
find a resemblance between all the sensitive and motor cere- 
bral nerves and the spinal ones, but it seems to me that 
analogy has been over overstrained. With regard to the nerve- 
fibres from the ganglia above mentioned, almost all observers 
agree in stating that the most part of them proceed in a peri- 
pheric direction, and accompany the cerebro- spinal nerves in 
their ultimate distribution. 
Besides these ganglionic fibres, which the cerebro-spinal 
nerves derive from their own ganglia, they receive others from 
the sympathetic. Anatomy shows that from the gangliated 
cord of the sympathetic seated on each side of the vertebral 
column nerve branches set out which connect it with the 
spinal nerves. Each branch on close investigation is found 
to consist of two bundles, the one composed of dark-bordered 
fibres, and the other of gray or gelatinous fibres. The fibres 
of the former seem to emanate directly from the roots of the 
spinal nerves, while those of the latter appear to take their 
origin in the sympathetic. On following the gray bundle to 
the spinal nerve, its fibres are seen passing for greater part 
* "On the Structure of the so-called Apolar, Unipolar, and Bipolar 
Nerve-cells of the Frog." ' Proceedings of the Royal Society,' vol. xii, 
No. 56, p. 569. 
