240 



THE LYMPHATIC SYSTEM 



more numerous in the ruminants, ox, sheep, etc., than in man. Their 

 size varies from that of a millet seed to that of a pea. In color they 

 closely resemble a minute extravasation of blood. 



These organs are essentially lymphatic structures in which the lym- 

 phoid tissue is arranged in the form of cords rather than in nodules. The 



FIG. 246. HEMOLYMPH NODE OF THE SHEEP. 



The dark areas are blood sinuses; the lighter portion within is lymphoid tissue. 



Photo. X 35. (After Warthin.) 



node is inclosed by a fibrous capsule, beneath which is a broad sinus filled 

 with blood. In this fact lies the chief distinguishing feature of these 

 glands. 



The peripheral blood sinus, which is analogous to the peripheral 

 lymph sinus of a lymph node, sends into the interior of the organ a 

 greater or less number of secondary sinuses. Based largely upon the 

 abundance of these secondary sinuses, the hemolymph nodes have been 

 divided into two varieties, named by Warthin (Jour. Bost. Soc. Med. 

 Sc., 1901) the 'splenolympli glands' and the ' 'marrowlym :./:// (jhtn da.' 



