660 
tion of the pia mater with the nervous fibres 
themselves. He also very properly cautions 
the dissector against a deceptive appearance 
connected with the passage of those blood- 
vessels which enter the lateral fissure, in 
order to reach the internal grey substance. 
“ Without due precaution,” he adds, * these 
vascular branches may themselves be readily 
mistaken for nervous fibrils; but they are es- 
pecially liable to be productive of error, be- 
cause, when they are made tense, they cause 
those portions of the longitudinal fibres of the 
cord, which are left between them to assume 
exactly the appearance of flat transverse fibres ; 
this circumstance probably misled Gall, and 
induced him to suppose that all the fibres of 
the spinal nerves were connected with the grey 
substance.” 
The following is Mr. Grainger’s account of 
the result of his examinations conducted with 
the precautions above specified. 
“ After repeated examinations, I satisfied 
myself that each root was connected both with 
the external fibrous part of the cord and the 
interna! grey substance. The following is what 
appears to be the structure: after the two 
roots have perforated the theca vertebralis, -and 
so reached the surface of the cord, it is well 
known that their fibres begin to separate from 
each other; of these fibres, some are lost in 
the white substance, whilst others, entering 
more deeply into the lateral furrows, are found 
to continue their course, nearly at a right angle 
with the spinal cord itself, as far as the grey 
substance in which they are lost. But this ar- 
rangement has no resemblance to the distinct 
division into fasciculi, depicted by Mr. Mayo; 
on the contrary, it is with great care only that 
small, delicate, individual threads or strie, as 
it were, are traced, dipping into the lateral 
fissure, and at length joining the grey matter. 
This difficulty is owing to the fact that whilst 
the fibres on the outer surface of the pia mater 
adhere very intimately with that strong mem- 
brane, on its inner surface, the membrane be- 
comes so extremely delicate, that the fibres 
lose much of their firmness, and break on the 
application of the least force; an accident 
which always happens if the pia mater be raised 
from the surface of the spinal cord, beyond the 
point where the nerves are attached. When 
the filaments have penetrated into the fissure, 
they lose their rounded figure and become flat- 
tened, and are then seen passing to the grey 
substance at a right angle to the longitudinal 
fibres. It is extremely difficult, owing to the 
delicacy of the parts, to determine the exact 
relations which exist between the above fila- 
ments and the grey matter; but in a few dis- 
sections 1 have been able to perceive these 
fibrils running like delicate striz in the grey 
substance. In one instance the fibres, being 
more distinct than usual, an appearance was 
presented having a remarkable resemblance to 
that which is seen on making a section of the 
corpus striatum in a recent brain, after the 
method of Spurzheim. My friend and col- 
league, Mr. Cooper, in this case counted dis- 
tinctly five separate fibrils passing from the 
NERVOUS SYSTEM. (Nervous Cextres. Tue Spina Corp.) 
anterior root of one nerve, and there were | ‘on 
other fibres derived from the same root, whir 
were not so plainly seen.” ‘& 
“ From numerous examinations,” contini 
Mr. Grainger, * I am induced to believe t 
whenever the white fibres of the nervous syst 
become connected with the grey substan 
whether in the different masses of the brain, 
the spinal cord, or in the ganglions, the 
rangement is similar to what is seen in t 
section of the corpus striatum to which re 
ence has just been made. The fibres become 
it were encrusted with the grey matter, a dis 
sition which may even be seen by a careful 
spection in the convolutions of the cerebre 
in which the radiating fibres of the crus 
rebri are observed like delicate striae.” = 
I have repeated the dissections of the ro 
of the nerves in the manner described 
Mr. Grainger, and am enabled to confirm 
general results. It appeared to me, howey 
that considerably the greater number of | 
fibres passed in at right angles, whilst th 
which might be sup to take an upw 
course were few and indistinct, and sé 
rather to pass obliquely inwards and lig 4 
upwards than to approach the vertical direct 
In short, when the fibres had penetrated 
medullary substance, they seemed to diy 
from one another,—those which occupie 
central position preserving much more of pa 
lelism than either the upper or the lower: 
It is extremely difficult to demonstrate 
direct continuity between the fibres o 
nervous roots and those of the cord. Va 
has, indeed, depicted the transition of 1 
fibres into the spinal cord (see fig. 330, p. 
as seen by the microscope; but these maj 
passing to the grey matter of the cord. 
continuity of the fibres of the nerves wit! 
longitudinal fibres of the cord would pro 
take place at the surface of the latter in gr 
numbers than at more deeply-seated p 
In the dissections above described, such 
would be very apt to be destroyed or 
overlooked. Mr. Grainger, in the work 
referred to, speaks evidently with mu ch § 
confidence of the connexion of the roots: 
nerves with the grey matter than of the’ 
tinuity with the longitudinal fibres. & 
presses his conviction, however, th ts 
continuity does exist, although the exact 
of connexion and the situation at whi 
occurs cannot be demonstrated, 
This question, respecting the preci: 
of the roots of the nerves to the cord, is 
those in which physiology in a certai 
takes the lead of anatomy. 
made it certain that while the spinal cor 
as a propagator of nervous power toa 
the brain, as in the ordimary se 
voluntary movements of the trunk 
ties, it is likewise capable of 
independent nervous centre, and that 
ments of a very definite character may 
duced in parts connected with it, even % 
communication between it and the bra 
been cut off. And it has been st 
one of the most zealous labourers in t 
peria 
