tion, when it has been once completely checked, is known as secondary. It arises either from giving way of the ligatures, or from the extension of sloughing to parts not previously implicated.

The amount of bleeding from a wound depends not only upon the kind and size of the cut vessels, but upon the manner in which they are divided. A wound crossing an artery will occasion more severe hæmorrhage than a longitudinal one, an incised wound more than one contused or lacerated, and a mere puncture more than a completely severed artery.

The arteries are always in a state of tension, and, when cut, the edges retract from each other, and contract upon themselves, so lessening their caliber. The outlets are choked by the coagulating blood, and, when there is much loss of blood, fainting ensues, the action of the heart becomes slower, and less blood is sent to the wounded part. In these three ways Nature tries to arrest hæmorrhage, and moderate bleeding will soon be checked spontaneously when the blood is in a normal condition.

The application of heat or cold favors the formation of clots and the arterial contraction; elevation of the injured part reduces the force with which the blood is sent to it; these will often be the only treatment required, but in more severe cases, when blood is spurting from a wounded artery, further measures become necessary.

The most important of these, and one usually calling for no further apparatus than one's own fingers, is pressure upon the bleeding point, or the vessels which supply it. There is no danger of serious hæmorrhage from a wound to which forcible digital pressure can be applied. If the bleeding vessel is too deep to be reached

by the finger, the wound can be plugged by a compress of lint. To make this most effectively, cut a number

FLESH

ARTERY
FLESH

FIG. 10.-Direct compression of a wound by means of what surgeons call a graduated compress, made of pads of lint, folded in different sizes, with the largest one on top.

of small bits, each a little larger than the preceding, and, beginning with the smallest, press them well into the wound. The pile should extend to some little height above the surrounding level, and be secured by a tight bandage. Such compression can only be made successfully over a bony surface; where the artery is imbedded in muscle, it becomes difficult if not impossible to control it. Wounds of the head and face, though they are apt to bleed profusely, can almost always be controlled by direct pressure, as the skull affords firm counter-pressure. If the bleeding artery can not be reached in this way, it, or the branches leading to it, must be compressed at some point nearer the source of supply. Thus, bleeding from a finger or toe can be stopped by making pressure on both sides of it, above the wounded point. So, in any case, firm compression of the bleeding vessel between the wound and the heart will arrest the flow of blood. In order to be able properly and promptly to apply such pressure in time of need, every nurse should familiarize herself practically with the course of the main arteries, know where to find them and how to control them. Actual experiment is the only way of rendering the information of much utility.

The aorta, the main trunk of the arteries, ascends from the upper part of the left ventricle for a short distance, then forms an arch backward over the root of the left lung, and descending upon the left side of the spinal column passes through the diaphragm into the abdomen. It is known in its different parts as the ascending and descending arch, the thoracic and abdominal aorta. From the arch of the aorta arise five branches the arteria innominata, the right and left coronary arteries, the left common carotid, and the left subclavian. Of these the innominata is the largest. It extends for only about two inches, and then divides into the right common carotid and right subclavian. The common carotids run up each side of the neck, and divide into the external and internal carotids, the one with its branches supplying with blood the face and outside of the skull, and the other penetrating to the brain, through an opening in the temporal bone. The coronary arteries return and supply the walls of the heart.

Each of the subclavians runs along a groove in the first rib, and it is against this that pressure is made to control the circulation in the shoulder and arm. It turns downward over this rib, and takes the name of axillary for a short distance, and then brachial. The brachial proceeds down the arm along the inner border of the biceps muscle to the front of the elbow, just below which it divides into the radial and ulnar arteries, which continue down the arm, one on each side, to the hand. In the hand, they and their branches reunite into a semicircle called the palmar arch. From this small arteries are sent off to each of the fingers. All these can be traced back to their origin at the arch of the aorta.

The aorta reaches as high as the third dorsal vertebra, then descending passes through the diaphragm at about the level of the twelfth dorsal. Opposite the fourth lumbar vertebra it divides into the right and left primitive or common iliac arteries. These are about two inches long. They diverge outward and downward, and, opposite the fifth lumbar vertebra and the sacrum, divide into the external and internal iliacs. The internal iliacs, after a course of about an inch and a half, are split up into numerous branches supplying the pelvic viscera.

Each external iliac continues downward and outward along the brim of the pelvis, and half-way between the anterior spine of the ilium and the symphysis pubis, runs under Poupart's ligament, and takes the name of femoral. The pulsations in this can be distinctly felt at the groin. It descends along the inner side of the thigh in a nearly straight line till it reaches the lower third, where it again changes its name and its direction, becoming the popliteal, and passing to the back of the thigh and down behind the knee. Here it divides into the anterior and posterior tibials, which run down either side of the leg, and finally anastomose into the plantar arch, as do the ulnar and radial arteries into the palmar. From the plantar arch, branches go to the toes.

The other principal branches of the descending aorta are the intercostals, the phrenic artery, the cœliac axis, and the superior and inferior mesenterics. These supply various internal organs.

The arteries most commonly compressed for the relief of hæmorrhage are the subclavian, the brachial, and the femoral. You should at least know how to find and

manage these. If pressure can not be made forcibly enough by the fingers, or if it needs to be maintained

for any length of time, a tourniquet can be used upon the brachial or femoral arteries. Before applying it, elevate the limb as high as possible, make a few turns of bandage about it to protect the skin, and place a hard pad directly over the course of the artery. In the absence of the regular apparatus, an impromptu tourni

quet may be made of a handkerchief or strip of muslin, with a hard knot or a smooth stone tied in the middle. Fasten this rather loosely around the limb and twist it with a stick, keeping the knot over the injured artery until pressure enough is made to completely occlude it. This is sometimes called a field tourniquet. It will be of no use whatever unless so fixed as to make pressure directly upon the main trunk of the artery. A tourniquet may remain on the arm for an hour, on the thigh for two hours, not more, as the part will die if its nutrition is cut off too long.

The subclavian artery can not be reached by a tourniquet. The handle of a large key or a blunt stick, suitably covered, may be pressed forcibly against it, behind the clavicle at the outer third of the first rib, in case of severe hæmorrhage from the shoulder or axilla.