ON INFLAMMATION. 
325 
Will congestion of the vessels, or the retarded progress of the 
blood account for the vivid redness of inflammation * or is not 
the brightness of the colour a demonstrable proof of the rapidity 
of the motion ? The blood retains its distinguishing arterial 
colour, and it only retains that while it is in motion: arrested 
even in an arterial vessel, it speedily becomes black and venous. 
It is only in the after stages of inflammation, and when the 
vessels have been over worked and debilitated, and can no 
longer contract upon their contents and hurry them forward, that 
congestion takes place; and then the vivid red disappears, and 
the dark and purple hue of venous blood succeeds. 
The redness is most observable at the point where the inflam¬ 
mation commenced, and where it is most intense, and to which 
the principal pain is referrible, because there the vessels are most 
laboriously employed, and there too they are first weakened, 
and congestion ensues, and the red will yield to the deeper 
colour. 
The redness occasionally occupies a very small and circum¬ 
scribed space, and abruptly breaks off, and the natural colour of 
the skin immediately succeeds. This will not be wondered at 
w hen the nature of these vessels is considered. They are pro¬ 
longations of the artery running into the parts in the immediate 
neighbourhood, for the important purposes of building up the 
frame, or producing the various secretions. They can scarcely 
be considered as branches of the artery. They are terminating 
fringes or filaments. They run their course in a few lines ; but in 
that small space they anastamose and re-divide, and form a 
mesh-work of vessels, and then terminate in the minute veins 
by which the blood, now changed in its character, is to be 
returned. The very circumscribed nature of the inflammation* 
its circular form, and its sudden termination, sufficiently de¬ 
signate the class of vessels that are affected. 
The minute calibre of the capillary vessels, and the important 
functions to be performed while the blood is traversing them, 
render it not improbable that the capillary circulation is natu¬ 
rally slow compared w ith the arterial. It is slow, that all tl e 
mysterious changes of the blood may be perfectly effected. 
The muscle of the vessel is sufficiently strong to propel the blood 
with the requisite velocity; but it is a diminutive muscle after 
all, and it is only when roused to unnatural exertion by the influ¬ 
ence of the organic nerves that the vessel is able to carry, and 
them uscle to propel, sufficient blood to produce the inflammatory 
blush. 
Heat is a characteristic of inflammation. The patients of the 
veterinarian cannot speak, and the increased temperature of the 
VOL. IV. Y v 
