The carotid artery, which ascends in the side of the neck and divides into the temporal artery which is distributed in the temple, and the facial artery which supplies the face, and also sends a branch called the _internal carotid_ to the parts within the skull. The sub-clavian artery, lying beneath the clavicle, or collar bone—that part of the continuation of this artery which passes through the axilla or arm-pit, is called the axillary artery; its continuation in the upper part of the arm, the brachial artery; and in the fore-arm it divides into the radial and ulnar arteries, which are distributed to the hands and fingers. The principal branches of the descending aorta are as follows: The iliac artery, which on passing into the thigh becomes the femoral artery, and, in the leg divides into the tibial and peroneal arteries, which form numerous branches for the supply of the leg and foot. Before dividing into the iliac arteries the descending aorta gives off several important branches, as the cœliac artery, from which the stomach and liver are supplied; the renal artery, which goes to the kidneys, and the mesenteric artery to the intestines; besides many other sub-divisions in various parts of its course. THE VEINS. The veins are the vessels which return the blood to the heart, after it has been circulated by the arteries through the different tissues of the body; they are much thinner in structure than the arteries, so that when emptied of their blood they become flattened and collapsed. The veins of the trunk may be divided into, the superior vena cava, with its formative branches, and the inferior vena cava with its formative branches. The superior vena cava is formed by the junction of the right and left vena innominata; it is a short trunk about three inches in length; it descends perpendicularly on the right side of the arch of the aorta, and terminates in the upper part of the right auricle of the heart. The right vena innominata receives the veins of the neck, which return the blood from the head as follows: The internal, external and anterior jugular veins—the external jugular vein being the one which is ordinarily open to let out the extravasated blood from the head—it will not be amiss to describe its course; it descends the neck in the direction of a line drawn from the angle of the lower jaw to the middle of the clavicle or collar bone, and terminates into the sub-clavian vein; it is variable in size, and replaced by two veins. The sub-clavian vein becomes the axillary vein near the arm-pit, and opens into the brachial veins down to the bend of the elbow, where it is divided into several branches which supply the fore-arm and the hand.