144 Progress of Foreign Scvence. 
any other cause, the part to which they go becomes motionless 
and insensible, It was, therefore, of consequence to know if the 
spinal marrow was not itself divided into two halves, the one de- 
stended to motion, the other to feeling. M. Magendie has dis- 
covered that the spinal marrow is formed, as it were, of two cords 
juxta-posited, one of which is endowed with an exquisite sensi- 
bility, while the other is, so to speak, a stranger to the property, 
and appears to be reserved for motion. Since it is shewn by the 
fine experinients of Legallois, that all the other organs, without 
exception, derive from the spinal marrow their sensibility and 
mobility, we are led to the remarkable conclusion, that we must 
cease to seek for any one point in the whole body where the sen- 
sibility and mobility are compounded together. Hence it seemed 
very probable that, in persons who lose the power of moving, 
while they retain their sensibility, and that reciprocally in those 
who lose sensibility retaining mobility, there is a disease in the 
one case of the motive cord of the spinal marrow, and in the 
other of the sensitive. A lunatic of the hospital of Charenton, _ 
had lost, for seven years, the faculty of motion in the whole body, 
although he retained its sensibility. He died last month. M. 
Royer Collard, physician to the establishment, made the ‘spinal 
marrow be examined with the greatest care, and found, in fact, a 
very marked alteration in the whole motive portion of the spinal 
marrow, while the portion where sensibility resides was perfectly 
sound. ‘The centre of the spinal marrow is devoid of sensibility; 
on touching it, no movements are excited in the body. It is on the 
surface of this organ, that its properties are developed under the 
double relation of movement and feeling. ‘Those who think that 
the electric fluid circulates habitually in our nervous system, may 
derive from this fact a new argument in favour of their opinion; 
for electricity diffuses itself, as is known, on the surface of the 
bodies which it pervades. It is unnecessary to remark, that the 
facts above related, should have a great influence in the treatment 
of different palsies. When the cerebral hemispheres of any ani- 
mal are put out of condition for acting, the animal runs straight 
forward, with singular rapidity, as if it were pursued. We might 
say, that an irresistible force presses and precipitates it. If, on 
the other hand, the action of the cerebellum be stopped, the 
moyements take an entirely opposite direction. The animal draws 
back; and it is a remarkable phenomenon to see a bird, for ex- 
ample, whose cerebellum has been slightly touched, for whole 
days make no attempt to walk, swim, or fly, unless it be back- 
wards. It would seem, therefore, to result from these experiments, 
that an animal in the ordinary state of health, is placed between 
two forces, which make an equilibrium, of which one would push 
it in advance, while the other would push it backwards. Volition 
would have the power of disposing at its option of these two forces. 
\ 
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