INFLAMMATION. 
391 
my readers in a clearer point of view. The temperature of any 
individual part of the body is governed and modified by the 
quantity of blood circulating within its vessels: whence that 
blood receives its caloric, and how the equilibrium is sustained, 
is quite a distinct affair, involving the oft-mooted question of 
animal heat: with that subject it is not our present intent to 
deal, suffice it to know that the heat of a part of the ani¬ 
mal frame depends upon the quantity of arterial blood con¬ 
tained within it, and the degree of rapidity with which that 
blood circulates. Now I have said that inflammation is an 
increased action of the arterial capillary system—that under 
this affection these minute tubes contract more forcibly than in 
a state of health, and that, in consequence of this more for¬ 
cible contraction, their elastic power is exerted with increased 
force in their dilatation, therefore not only their action but 
their capacity likewise is magnified. How does this operate 
in producing a greater determination of blood ? Imprimis, the 
powerful contraction of the muscular coat is followed by a cor¬ 
responding reaction in the elastic coat, producing a greater 
dilatation of, and a consequent greater capacity in, the tube: 
in the progress of this dilatation an attempt is made to form a 
vacuum; but, in obedience to an established law in natural phi¬ 
losophy, the blood from the supplying trunks rushes forward to 
fill up the intended vacuum. The same process is then repeated ; 
there is the same powerful contraction, the same consequent 
increased dilatation, and the same flow of blood ; thus, not only 
the capillaries, but the arterial trunks also, after a time, per¬ 
form a greater degree of labour than in a state of health : this is 
plainly manifested to us by the powerful throbbing of the meta¬ 
carpal artery, for instance, in inflammatory diseases of the foot. 
As an inevitable consequence of this, an increased quantity of 
blood circulates through any portion of the body when in an 
inflamed state, giving off an extra portion of caloric in a given 
space, and therefore imparting to us a sensation of increased 
heat. This symptom is invaluable to us as veterinary surgeons, 
as having to do with patients that cannot speak to us, and 
point out the seat of pain, and whose bodies have got a pilous 
covering, preventing us from availing ourselves of another im¬ 
portant character of inflammation, viz. redness. How many 
cases of lameness have we brought to us, without any visible 
external sign by which we can know the seat of the affection, 
or be able to form an opinion as to its nature, or its extent; but 
by the aid of the heat which is present, we are made acquainted 
with these circumstances, and thus enabled to direct our reme¬ 
dial means and appliances to the proper quarter. The veterinary 
