CHAP. XI.] 



THE VASCULAR SYSTEM. 



125 



and also in the thorax and abdomen, especially in the mesentery, 

 where they are called the mesenteric glands, and alongside 

 of the aorta, vena cava inferior, and the iliac vessels. A few, 

 usually of small size, are found on the external parts of the 

 head, and considerable groups are situated in the axilla, and 

 in the groin, where they receive the name of inguinal glands. 

 Some three or four lie on the popliteal vessels, and usually one 

 is placed a little below the knee, but none farther down. In 

 the arm, they are found as low as the elbow joint. 



The size of the lymphatic glands is very various, some being 

 not much larger than a hemp seed, and others as large as an 

 almond, or even larger than this. In shape, they are usually 

 oval. 



A lymphatic gland is covered by an envelope, or capsule, of 

 connective and muscular tissue. This capsule sends fibrous 



FIG. 86. DIAGRAMMATIC SECTION OF LYMPHATIC GLAND. (Sharpey.) a./, 

 afferent lymphatic; e.l, efferent lymphatic; c, capsule, or envelope; tr, trabeculae; 

 l.s, lymph-sinus ; l.h, pulpy substance of gland. 



bands (trabeculce) into the substance of the gland, dividing the 

 exterior portion into more or less regular compartments, and 

 the interior into irregular labyrinths. This framework is occu- 



