PHYSIOLOGY OF THE NERVOUS SYSTEM.’ 
what exalted. The slightest touch upon the 
surface of the body, even a breath of wind 
blown upon it, will cause a general or partial 
convulsive movement. The whole extent of 
the spinal cord is in a state of excitement, and 
even the medulla oblongata may be involved 
in it, whence the closed jaws, the spasmodic 
state of the facial muscles, the difficult degluti- 
tion. When this polar excitement is raised to 
its highest degree, the slightest mechanical sti- 
mulus applied to any one point of the cord 
affects the whole organ and throws all the mus- 
cles which it supplies into spasmodic contrac- 
tion, just as the least stimulus to peripheral 
parts has the same effect. 
It is a very interesting fact, which I have fre- 
quently satisfied myself of by careful examina- 
tion, that, however great the polar excitement 
may have been into which the cord has been 
thrown by strychnine, it exhibits no change of 
structure which can be detected by our means 
of observation. The nerve tubes and other 
elements entering into the formation of the 
cord have preserved their natural appearance 
in all the cases which I have examined. 
Opium has the effect of creating a similar 
State of polarity in the cord. This is most.con- 
spicuous in cold-blooded animals ; it produces 
a similar effect in the warm-blooded classes, 
but in a much less degree. Hence there is 
an objection to the use of opium in large doses 
in cases of tetanus; and experience has shewn 
the inefficacy and the injurious influence of tbis 
drug when administered in large quantities. 
When the cord is in this state of excitement, a 
stimulus applied to one part may excite a re- 
mote part of it with great facility. 
The curious tendency already referred to, 
which the male frog has to grasp objects. pre- 
sented to them by his anterior extremities, is to 
be attributed in part toa spontaneous exaltation 
of the polar foree of the cord which takes place 
at the copulating season, in the spring of the 
year, and which is associated with an extraor- 
dinary developement of the papillary texture of 
the integument of the thumb. 
This exaltation of the polar force of the cord, 
in connection with the generative function, is a 
point highly worthy of the attention of the 
physiologist as offering some explanation of the 
sympathy which exists between different organs, 
between those even which are remote from 
each other, during the rutting season, or during 
utero-gestation. 
It is worthy of notice here that cold has a 
considerable influence in controlling this polar 
State of the spinal cord, and of other nervous 
centres likewise. Ice applied along the spine, 
or the cold douche, may be frequently em- 
ployed with great benefit in cases of muscular 
disturbance dependent on this polar state of the 
cord. It seems to me more than doubtful that 
many of those drugs which have the character 
of possessing a sedative influence upon the 
nervous system can be employed for this pur- 
pose either with safety or advantage. This 
applies certainly to hydrocyanic acid and to 
opium in large doses; animals poisoned by 
these substances become convulsed before 
721i 
death, and this denotes their tendency to exalt 
the polarity of the cord. Conium and bella- 
donna, according to my experience, exercise the 
most beneficial influence of any of the sedative 
drugs, and I have found them very useful in 
restraining the cramps and startings in para- 
plegic cases. 
I have ascertained by several experiments 
that the inhalation of ether has considerable 
effect in controlling the natural polar state 
of the cord, as well as that which may be 
produced by strychnine. A pigeon deprived of 
its cerebral hemispheres lives in a state of sleep 
for a considerable time; it flies when thrown 
in the air, spreading and flapping its wings ; 
stands when placed on its feet. A bird thus 
mutilated was made to inhale ether; it could 
not stand, and when thrown into the air it fell 
to the ground like a heavy log, its wings 
remaining applied to the sides of its body, or 
if the wings were drawn out as it was thrown 
into the air, they quickly collapsed. As soon 
as the effects of the ether had passed off, it 
stood and flew as before. I gave strychnine to 
a rabbit, a guinea-pig, and a dog, so as to 
excite the tetanoid state. Immediately the 
spasms showed themselves, I brought it un- 
der the influence of ether; the spasms ceased 
immediately, and the animal became perfectly 
relaxed ; but as soon as the effects of the ether 
passed off, the spasms came on again, but were 
soon subdued by a fresh inhalation of ether. 
And thus I found that the life of an animal 
poisoned by strychnine could be greatly pro- 
longed through successive inhalations of ether ; 
for animals of the same kind, poisoned by 
equal doses of strychnine, but not subjected 
to the influence of ether, perished very rapidly. 
The examples which show that the spinal 
cord possesses the power of reflecting sensitive 
impressions are chiefly derived from disease. 
Every practitioner is familiar with the pain in 
the knee which accompanies the early stages of 
disease of the hip joint. The patient some- 
times refers his sufferings so exclusively to the 
former joint, that the disease of the latter may 
be entirely overlooked by his medical atten- 
dant. Yet the really painful part is healthy, 
while the hip joint is the seat of a morbid 
process. The pains which are felt in the thighs 
from the presence of a stone in the bladder, 
and the itching which is referred to the extre- 
mity of the prepuce from the same cause, are 
phenomena of the same nature. Pain in the 
right shoulder from irritation of the liver is a 
well-known sympathetic sensation : sometimes 
this pain extends over a very large surface. 
Numerous other instances of similar sympa- 
thetic phenomena might be adduced, but the 
above are sufficient for our present purpose. 
Taking into account the well-proved fact that 
nerves form no real junction of their fibres 
in their anastomoses, and that there is no more 
than a simple juxta-position of the nerve-tubes 
in these anastomoses, it is plain that we must 
trace these fibres up to the nervous centres to 
discover any connection between the fibre first 
irritated and that to which pain is referred. In 
the case of hip-joint disease, the nerves of the 
