AN INQUIRY REGARDING THE PARTS OF THE 
NERVOUS SYSTEM WHICH REGULATE THE 
CONTRACTIONS OF THE ARTERIES 
[Philosophical Transactions, Part II for 1858, p. 607.] 
Received June 18—Read June 18, 1857.' 
GREAT light has been thrown in recent times upon the nature of the in- 
fluence exercised over the blood-vessels by the nervous system. In 1852 it was 
shown by M. Bernard that division of the sympathetic nerve in the neck of 
a cat, or other mammalian, was followed by turgescence of the blood-vessels 
of the ear, and increased heat of that part and of the whole side of the face, 
together with contraction of the pupil. Early in the following year Mr. Augustus 
Waller performed the converse experiment of galvanizing the sympathetic 
above the point where it had been cut or tied, with the very striking result 
of rapid subsidence of the turgescence of the vessels, and fall of the temperature 
of the face ; while the pupil became so extremely large, as to imply that the 
dilating fibres of the iris were thrown into a state of energetic contraction. 
From these experiments it appeared to follow pretty clearly that the 
sympathetic nerve in the neck presides over the contraction of the vessels of 
the face, which, becoming relaxed and dilated when the influence of the nerve 
was removed by its division, allowed the blood to flow through them in larger 
mass than before ; but on the other hand, when excited to extreme constriction 
by the galvanic stimulus applied to the nerve, permitted but little blood to pass. 
This conclusion appears to be confirmed by the observation since made by 
Brown-Séquard, that the elevation of temperature which occurs in Bernard’s 
experiment is never greater than is to be accounted for by the increased mass 
of warm blood which must be sent through the part, on the hypothesis that the 
turgescence of the vessels is simply the result of their dilatation. It was further 
shown by Messrs. Waller and Budge, that the same region of the spinal cord 
which they had previously ascertained to preside over dilatation of the pupil, 
* This paper, and that on the ‘Cutaneous Pigmentary System of the Frog’ (p. 48 of this volume), 
were read as supplements to the ‘Essay on the Early Stages of Inflammation’ (p. 209 of this volume). 
The author has since extended his investigations into the subject of the present memoir, in accordance 
with a recommendation from the Council, and the results have been incorporated into the text, all new 
matter thus introduced being indicated as such either by date or by note at the foot of the page. 
* Comptes Rendus, vol. xxxvi, p. 378. 
