THE VASCULAR SYSTEM. 15 l 



penis, two or three iliac glands are near the origin of the 

 femoral artery, and a few small lumbar glands lie in the 

 lumbar region of the abdominal cavity. 



All parts of the body have communication with the 

 lymphatic vessels, which for the most part are so small as 

 to be invisible unless injected, when they are easily recog- 

 nized by their beaded appearance caused by the numerous 

 valves within them. There are two systems of vessels in 

 the head and extremities the superficial and the deep. The 

 former accompany mainly the superficial veins, and the lat- 

 ter follow the deep veins. On the outer aspect of the tho- 

 racic limb just beneath the skin two vessels are present, 

 which flow into the cervical glands. They carry the lymph 

 from the ball of the foot and the skin of the foot and 

 forearm. One or two deep lymph-vessels are found ac- 

 companying the brachial vein and artery, which convey the 

 lymph from the bones and muscles of the arm to the axil- 

 lary gland. 



In the pelvic limb two or three superficial vessels are 

 present transmitting the lymph from the foot to the pop- 

 liteal gland, whence two vessels proceed to the deep lym- 

 phatic system. The lymph from the bones and muscles of 

 the leg reaches the iliac glands through two or three deep 

 vessels lying near the femoral vein and artery. The in- 

 guinal glands receive most of the lymph from the skin of 

 the leg. 



The lymph from the superficial parts of the head flows 

 largely into the submaxillary glands, while that from the 

 brain, tongue, esophagus, and larynx empties into the 

 laryngeal glands. 



The lymph of the right forelimb, right side of the neck 

 and head, and right side of the thoracic wall is received by 

 the right tracheal trunk. The left tracheal trunk receives 

 the lymph from the left side of the head, neck and thoracic 



