PULSE :—WOUNDS OF ARTERIES. 237 
purpose is the radial artery (fig. 124) at the wrist; but the 
carotid artery in the neck, and.the temporal artery in the 
temple, may be felt, when it is desired to know the force of 
the circulation in the head; as may the arteries supplying 
other parts, when we wish to gain information respecting 
the organs they supply. An increased action in the organ, 
whether this be due to inflammation, or to a state of unusual 
activity of its function, causes an increase of size in the artery 
which supplies it; and thus the pulsation may be unusually 
strong in a particular trunk, when the heart/ s action and the 
general circulation are not in a state of excitement. For 
instance, a whitlow on the thumb will occasion its artery to 
beat almost as powerfully as the radial artery usually does; 
and excessive activity of the mind, prolonged for some hours, 
greatly increases the force of the pulsations in the carotid 
arteries, from which the brain is chiefly supplied. 
277. When an artery is wounded, there is often great 
difficulty in controlling the flow of blood; for pressure can 
seldom be effectually applied in the situation of the wound; 
and the surgeon is generally obliged to tie the vessel above 
the orifice. As a temporary expedient, the loss of blood may 
be prevented by making firm pressure upon the artery above 
the wounded part, that is, nearer the heart; and many valu¬ 
able lives have been saved by the exercise of presence of 
mind, guided by a little knowledge. The best means of 
keeping-up the requisite pressure, until the proper instrument 
(the tourniquet) can be applied, is to lay over the artery (the 
place of which may be found by its pulsation) a hard pad, 
made by tightly rolling or folding a piece of cloth; this pad 
and the limb are then to be encircled by a bandage, by which 
the pressure is maintained ; and this bandage may be tightened 
to any required degree, by twisting it with a ruler or a piece 
of stick. Thus a constant pressure may be exercised upon 
the artery, which will be generally sufficient to control the 
bleeding from it. But there are, unfortunately, many cases 
in which pressure of this kind cannot be applied; as for 
instance when the femoral artery is wounded high up in the 
thigh, or the carotid artery in the neck. And nothing else 
can then be done, but to compress the artery with the thumb, 
or with some round hard substance (such as the handle of an 
awl), until proper assistance can be obtained. 
