178 THE ORGANS 



out to the capsule. From the peripheral sinus branches extend into 

 the interior of the node, separating the lymphoid tissue into cords or 

 islands. The relative proportion of sinuses and lymphoid tissue 

 varies greatly, some nodes being composed almost wholly of sinuses, 

 while in others the lymphoid tissue predominates. There is usually 

 a fairly distinct Jiilum. In many glands no differentiation into cortex 

 and medulla can be made. Where there are a distinct medulla and 

 cortex the peripheral lymphoid tissue is arranged in nodules as in the 

 ordinary lymph node. Reticular connective tissue crosses the sinuses 

 and supports the cells of the lymph nodules and cords (Fig. 104). 



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Fig. 104. — Section through Superficial Portion of Human Hasmolymph Node 

 (Marrowlymph Node). (Warthin.) Capsule, trabeculse, and parts of two adjacent 

 nodules; sinuses filled with blood; among the lymph cells are large multinuclear 

 cells resembling those of marrow, nucleated red blood cells, etc. 



The cellular character of the lymphoid tissue has led to the sub- 

 division of hasmolymph nodes into splenolymph nodes and marrow- 

 lymph nodes. In the splenolymph node the lymphoid tissue resembles 

 that of the ordinary lymph node of the spleen. In the marrow- 

 lymph node, which is the much less common form, the lymphoid 

 tissue resembles red marrow. There are no distinct nodules, and 

 there is a quite characteristic distribution of small groups of fat cells. 

 The most numerous cells are eosinophiles and mast cells (see page 

 no). Polynuclear leucocytes and large leucocytes with a single 

 lobulated nucleus are less numerous. The very large multinuclear 

 cells of red marrow are also found, but usually in small numbers. 



