132 NORMAL HISTOLOGY. 



the first place, of a framework of reticular connective 

 tissue, whose meshes are largest in the centre of the 

 nodule, narrower and smaller in the periphery ; in- 

 deed, so closely crowded together are the trabecuke 

 here, that they give to the nodule a tolerably well- 

 defined outline. In the second place, the meshes of 

 the reticulum are closely filled with small spheroidal 

 cells, having, in general, the characters of lymph- 

 cells ; in many of them, however, the nucleus is very 

 large, occupying the greater part of the cell. The 

 nodules do not entirely fill the cavities in which 

 they lie, but are surrounded on all sides by a narrow 

 space. 



If we examine the relation of the nodules to the 

 walls of their investing spaces, we find that, from 

 the walls of these spaces, delicate branching trabecu- 

 lae pass inward to the surface of the nodule, where 

 they become continuous with the reticular tissue of 

 the latter. They are, in fact, themselves reticular 

 connective tissue, similar to that of the nodule, ex- 

 cept that the trabeculae are coarser and the meshes 

 broader. Stretching across the space surrounding 

 the nodules, they suspend the latter so that they 

 hang free in the cavities. The space thus formed 

 around the nodule is called the peri-nodular space, 

 or, better, lymph-sinus, for reasons which will be 

 presently given. 



If we now turn our attention to the lymph-cords 

 of the medulla, which, it will be remembered, are 



