=The Fascia.=—The fascia (fascia, a bandage) is areolar or aponeurotic tissue of variable thickness and strength found in all regions of the body and invests or surrounds the softer and more delicate organs. From its situation in the body the fascia is divided into two groups, superficial and deep. _Superficial fascia_ is found immediately beneath the skin over almost the entire surface of the body. It connects the skin with the deep fascia and consists of areolar tissue. The superficial fascia varies in thickness in different parts of the body and some places, especially in the groin is capable of being subdivided into several different layers. The first layer of the superficial fascia, which is just beneath the skin, usually contains a great amount of fat or adipose tissue. This, in most text books, has been termed the subcutaneous tissue. The second layer is comparatively devoid of adipose or fatty tissue and in this we find the trunks of the subcutaneous vessels and nerves, as for example, the radial and ulnar veins in the arms and the saphenous vein in the leg. The superficial fascia facilitates the movement of the skin, serves as a soft medium for the passage of the vessels and nerves to the skin and retains the warmth of the body, since the fat contained in its meshes is a had conductor of heat. _Deep fascia_ or aponeurotic fascia is a dense inelastic, unyielding fibrous membrane, forming a sheath for the muscles and affording them broad surfaces for attachment. On removal of the superficial fascia, the deep fascia is usually exposed and can be seen as a dense, tough membrane, which not only binds down the muscles to each region, but gives to each a separate sheath as well as to the blood vessels and nerves. Thus, on going down into the arm between the biceps and triceps muscles to raise the brachial artery, you would first cut through the skin, then the subcutaneous tissue, the superficial fascia and then you would come to a membrane investing the artery, vein and nerve. This membrane is the part of the deep fascia which covers the vessels, making a distinct sheath for them and you must go through this sheath before you can hope to raise the artery. [Illustration: FIG. 3—Lymphatics of the head and neck. B, the thoracic duct.]