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XII. On the nervous circle which connects the voluntary muscles 
with the brain. By Charles Bell, Esq. Communicated by 
the President , January 25, 1826. 
Read February 1 6, 1826. 
In the Papers which I have had the honour of addressing 
to the Society on the arrangement of the nerves of the 
human body, I have proceeded upon a comparison of the 
nerves of the spinal marrow with the nerves of the en- 
cephalon. 
It was shown that the former were compounded of fila- 
ments possessing different powers, and that each nerve, having 
several properties or endowments collected within itself, 
proceeded to its destination without intricacy. 
Unless we had discovered the composition of the roots of 
these nerves, we should have continued to suppose that one 
nerve was simple in its structure, and yet capable of bestow- 
ing the very different properties of motion and sensation. 
But having satisfied myself that the roots of the spinal 
nerves had distinct powers, I followed up the columns of the 
spinal marrow ; and with a knowledge of the composition of 
these nerves as a key, I examined the different properties of 
the nerves of the encephalon. Here, in the head, the nerves 
arise simply, and diverge to their destinations without the 
close compact or union which the spinal nerves form ; and 
accordingly, the anatomy of these nerves of the brain affords 
satisfactory proof of their uses or functions. I am about to 
