ees 
a> O- eee 
ee 
. 
PHYSIOLOGY OF THE NERVOUS SYSTEM. 
flex, and these two kinds have an immediate 
but unknown relation to each other, so that- 
before the Royal Society on February the 16th and 
23d, and March the 2d, 1837, but was uot pub- 
lished in the Transactions. This paper is entitled, 
“© On the trne Spinal Marrow and the Exciio- 
motory System of Nerves.” 
The object of this paper the author states to be 
the developement of a great principle in physio- 
logy—that of the special function of the true spinal 
marrow and of a system of excito-motory nerves. 
*« It is this principle,” he continues, ‘‘ which 
Operates in all those actions which have been de- 
signated sympathetic, which regulates the func- 
tions of ingestion and expulsion in the animal 
economy, and which guards the orifices and sphinc- 
ters of the animal frame.” 
«< The principle to which I allude,” he proceeds, 
*« has been confounded with sensation, and vo- 
luntary, and what has been designated instinctive, 
motion, by all (sic) physiologists, with one single 
pescption (Sir Gilbert Blane). It has been sup- 
to be a function of the rational (Stahl) or 
irrational (Whytt) sonl. It has been considered 
by some (Haller, &c,) as attached to the brain; 
by others (Whytt, Soemmering, Alison, Muller, ) 
as attached to the brain and spinal marrow; by 
others (Le Gallois, Flourens, Mayo,) as peculiarly 
attached to segments of the spinal marrow ; it has 
been viewed by others as the function of the sym- 
pathetic (Tiedemann, Lobstein,) or of the pneu- 
mogastric nerve (Bell, Shaw); and, lastly, by 
others as operating through identity of origin or 
anastomoses of nerves (Mayo).” 
How very strange it is that amidst all the re- 
search displayed in this paragraph, no mention 
should have been made of Unzer and Prochaska, 
the only authors who really had clearly stated the 
correct doctrine respecting nervous phenomena in- 
dependent of the mind !! 
n this paper Dr. Hali falls into the curious error 
of affirming that the power which is developed in 
the nervous system in connection with sensation 
and volition, is different from that through which 
the reflex actions are produced. To the latter he 
limits the term vis nervosa, and, having quoted 
Haller’s very correct description of the course 
which it takes in motor nerves, he affirms that his 
Tesearches have disclosed a series of phenomena 
** directly at variance with the conclusions of 
Haller.” 
I confess myself quite unable to discover in what 
respect Dr. Hall’s results are at variance with the 
laws of the vis nervosa as laid down by Haller. All 
that the latter physiologist affirmed was that the 
nervous force travelled from trunk to branches in 
motor nerves, and that irritation of the spinal cord 
caused convulsions of the limbs which derived their 
nerves from below the point of stimulation. Now 
these facts are strictly true—by whatever stimulus 
the nervous force is excited in motor nerves it travels 
from trunk to branches; and the statement made 
by Haller respecting the spinal cord is equally true, 
namely, that the motor force travels downwards, 
and that irritation of the cord affects only the 
limbs below the irritated point. All that Dr. Hall 
has made out which is at variance with this pro- 
position is, that sometimes the anterior extremities 
may be thrown into action by stimulating that seg- 
ment of the cord from which the posterior extre- 
Mities derive their nerves, from whence he con- 
cludes that “‘ the motor power in the spinal mar- 
row will act in a retrograde direction.” 
This conclusion, however, does not follow from 
the experiments adduced in support of it. If the 
spinal cord of a turtle be irritated in the segment 
from which the nerves to the hinder extremities 
Spring, and all four extremities are thrown into 
action by that stimulus, we are not authorized to 
conclude that the motor power will act in the spinal 
721x 
each afferent nerve has its proper efferent one, 
the former being excitor, the latter motor. 
marrow in a retrograde direction; all that we°are 
justified in affirming is that the same change which 
would excite the nerves of the irritated part of it 
may be propagated from its lower to its upper part. 
How this takes place is uncertain, whether by sen- 
sitive fibres or by commissural fibres, or by vesicular 
matter, most probably by the last. 
It may, however, be stated that such phenomena 
as those described take place chiefly in an excited 
state of the cord, as when the animal is under 
the influence of. strychnine—or in tetanus—and 
their occurrence is far from being in accordance 
with a normal state of action of the spinal cord. 
I have frequently irritated the cord in healthy 
animals without producing any movements save 
in parts below the point stimulated. (Vide supra, 
p. 721G.) 
Dr. Hall in this paper draws the same conclusions 
as in his work last referred to as to the existence of 
a “ true spinal marrow physiologically distinct from 
the chord of intra-spinal nerves ; of a system of 
excito-motory nerves, physiologically distinct from 
that of the sentient and voluntary nerves ; and of a 
nervous influence—the excito-motory power—ope- 
rating in directions incident, upwards, downwaids, 
and reflex, with regard to the true spinal marrow, 
the centre of this excito-motory system.” When 
Dr. Hall uses the term physiologically distinct, of 
course he means, likewise, anatomically distinct. 
One part cannot be physiologically distinct from 
another without being anatomically so also. 
In the second section of this paper Dr. Hall gives 
**a slight sketch of the opinions of physiologists 
upon the subject of this memoir.”” He alludes to 
the views of Haller, Monro, Whytt, Blane, Le Gal- 
lois, and the Reporters of the Institute upon Le 
Gallois’ Essay, Mayo, Flourens, Alison, and Mul- 
ler, but makes no allusion to either Unzer or Pro- 
chaska. 
I pass over the third, fourth, fifth, and sixth sec- 
tions, and proceed to the seventh. Here the laws 
of the excito-motory system are stated, and those 
extravagant powers are attributed to it, which I 
have in the text endeavoured to show it cannot 
exercise. But, in addition, this system is made to 
be’the nervous agent of the appetites and passions ! 
What strange confusion! that a system, devised as 
the special centre of nervous actions independent 
of the mind, should be the seat of phenomena 
preeminently mental, and intimately connected 
with sensation. 
The remainder of this essay consists of further 
remarks on the anatomy, physiology, pathology, 
and therapeutics of the excito-motor system, and 
concludes with some observations on the ganglionic 
system of nerves. 
In 1841 Dr. Hall published his work on the Dis- 
eases and Derangements of the Nervous System. 
In this work I am not aware that any new or addi- 
tional fact has been stated not mentioned in those 
already quoted, It includes a reprint of several 
memoirs read to the Medico-Chirurgical Society. 
In 1843 a ‘* New Memoir on the Nervous System” 
appeared, dedicated to Professor Flourens as to 
one ‘* who has in his responsible office displayed 
the most candid, impartial, and generous judgment 
of the works of others.” 
I find it necessary to notice an assertion con- 
tained in a note to the advertisement of this work 
Dr. Hall observes :— 
«« My first memoir was entitled, ‘ On the Reflex 
Function of the Medulla Oblongata and Medulla 
Spinalis.’? This important function as the nervous 
agent in all the acts of ingestion and of egestion in 
the animal economy was previously unknown. It 
is not mentioned by Whytt, or Prochaska, or any 
other author; who, however they may cite the 
term reflex, or detail experiments, or treat of sym- 
