THE FUNCTIONS OF THE NERVOUS SYSTEM. 
267 
from which are sent to every part of the body nerves proved by direct experi- 
ment to convey the influence of every part of them ; and this combined influence 
of the brain and spinal marrow is employed in forming the various secreted 
fluids, and supporting the other processes on which the due structure of every 
part depends ; and I have in a treatise entitled “ On Indigestion” pointed out 
how extensively the phenomena and treatment of all diseases are influenced by 
this cause. 
Such then is the relation which subsists between the nervous system and the 
other vital organs I have had occasion to mention ; but there is another rela- 
tion of that system which must be considered before the nature of its functions 
can be clearly understood. 
The nervous system, in the usual acceptation of the term, is very ill defined, 
and functions of the most dissimilar nature are classed together under the 
general denomination of nervous. Those of sensation and volition, for example, 
are classed with the excitement of a muscle and the formation of a secreted 
fluid. It seems highly improbable that results so different should arise from 
the same or similar causes. On the most cursory view of the subject, we can- 
not help supposing that the nervous system, according to the common accep- 
tation of the term, includes more than one principle of action. We have every 
reason to believe, that the sensorial is a power wholly distinct from that strictly 
called nervous ; and all doubt seems to be removed by the circumstance, that 
although the organs of both belong to the nervous system, it is evident they 
are not the same organs, because the sensorial power resides chiefly in the brain 
while the nervous power, properly so called, resides equally in the brain and 
spinal marrow ; the latter of which organs is capable of its functions inde- 
pendently of the former, as appears from many of the experiments of Le 
Gallois, which have been confirmed by several of my own. 
It occurred to me on reviewing the whole of these circumstances, that as we 
can destroy the nervous, without at all impairing the muscular power, it might 
be possible to remove the sensorial power without immediately destroying that 
more strictly called nervous. 
I made many experiments, which are detailed in my treatise on the Vital 
Functions, for the purpose of determining this point ; from which it appears that 
in all modes of death, except the most sudden, (arising from a violent and 
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