28 ON THE PARTS OF "THE NERVOUS SYSTEM 
namely, the part included between the last cervical and third dorsal vertebrae, 
also regulated the vessels of the face. When that part of the cord was removed, 
turgescence of those vessels occurred ; but galvanizing the anterior roots of 
the spinal nerves proceeding from that part produced the same effect as irrita- 
tion of the sympathetic, namely, pallor with diminished temperature.’ M. Schiff 
afterwards ascertained, that after destruction of the lower part of the cervical 
and upper part of the dorsal region of the cord in bats, there is an immediate 
dilatation of the small vessels of the wings,? and Brown-Séquard had pre- 
viously shown that after transverse section of the spinal cord in the lumbar 
region in birds and mammals, an increase of 1°, 2°, or 3° Fahr. took place in 
the temperature of the paralysed parts.* All these facts tend to the same con- 
clusion, namely, that the spinal cord is the part of the nervous centres which 
presides over the blood-vessels, and that one important action at least which 
it induces in them is constriction of the circular coat of the arteries. But there 
still remains, I believe, some difference of opinion with regard to the inter- 
pretation of Bernard’s experiment ; and there might be some colour for the 
idea that the red and turgid state of the vessels seen after division of the sym- 
pathetic in the neck was due to a change in the blood, such as occurs in inflam- 
mation, and that the pallor ensuing upon galvanizing the nerve was the result 
of a return of the vital fluid to its normal condition after restoration of nervous 
influence. But all ambiguity of this kind seems to me to be removed by some 
observations made several years ago by Mr. Wharton Jones upon the frog. 
This animal is peculiarly adapted for investigations on this subject, because both 
the calibre of the vessels and the state of the blood as it flows through them can 
be observed with the utmost facility in the web ; and Mr. Jones found that divi- 
sion of the sciatic nerve was followed by dilatation of the arteries, but that this 
increase of calibre, so far from being caused by an obstruction in the progress 
of the blood, was accompanied with unusually free and rapid flow through the 
capillaries. But with regard to the part of the nervous system which regulates 
the contractions of the arteries, some more recent observations by the same 
author are at variance with the conclusion above drawn from experiments by 
others upon mammalia. For he states that the division of the roots of the 
sciatic nerve within the spinal canal failed to produce dilatation of the vessels ; 
whence it was inferred that the sympathetic fibres of the sciatic trunk, as 
distinguished from those derived from the cord, are the channels through which 
" Comptes Rendus, vol. Xxxi, pp. 377, 575- 
* Gazette Hebdomadaive de Méd. et de Chir., 1854, pp. 421, 424. 
* Experimental Researches, New York, 1853, p. 8. 
* «Essay on the State of the Blood and the Blood-vessels in Inflammation,’ by T. Wharton Jones, Esq., 
F.R.S. Guy's Hospital Reporis, vol. viii, p. 12. 
