66 



CONNECTIVE TISSUE CARTILAGE BONE 



a deeply staining nucleus enveloped by a narrow shell of homogeneous 

 slightly basophilic cytoplasm. The lymph cells (lymphocytes) are so 

 closely packed that it is almost impossible to distinguish the fine threads 

 of the reticular stroma, except in those portions where some of the 

 lymphatic cells have been washed out or displaced in the preparation of 



the specimen.* 



The density of the lymphoid 

 tissue varies much, however, in dif- 

 ferent organs and even in different 

 portions of the same organ. The 

 denser accumulations of lymphoid 

 corpuscles may form either ovoid 

 lymph nodules or follicles, or long 

 dense trabeculaB, the lymphatic 

 cords, which are surrounded by 

 looser portions of lymphoid tissue. 

 Lymphatic corpuscles are fre- 

 quently infiltrated into the connec- 

 tive tissue of the mucous mem- 

 branes, where they form irregular 

 collections, which may be termed 

 diffuse lymphoid tissue, in contra- 

 distinction to compact lymphoid 

 tissue, which occurs in the lymph 

 nodes, tonsils, thymus, and spleen, 

 and in the aggregate and solitary 

 nodules of the intestinal canal. 

 Diffuse lymphoid tissue is found in 

 the mucous membranes of (A) the 

 respiratory tract nose, nasophar- 

 ynx, larynx, trachea, and bronchi; 



FIG. 80. FROM A SECTION THROUGH THE 

 MEDULLA OF A CERVICAL LYMPH NODE 



OF MAN. 



a, a 'cord' of dense lymphoid tissue; 

 b } looser lymphoid' tissue of the medullary 

 sinuses; c, the margin of a fibrous tra- 

 becula; d, nucleus of the connective tis- 

 sue reticulum; e, endothelial lining of the 

 lymphatic sinus. Hematein and eosin. 



X475. 



and (B) the alimentary tract 



mouth, tongue, pharynx, esophagus, stomach, and intestines. 



In the basement membranes of certain tubular glands e.g., sweat, 

 kidney, tear and mammary and in the peripheral portion of the large 

 cells of the umbilical cord, Mallory (Jour. Med. Res., 1903 and 1905) 



* Mall's technic for this purpose consists in injecting gelatin into a fresh 

 lymph organ (e. g., spleen), freezing the tissue, and placing thin sections into 

 warm water when the lymphocytes are largely carried away by the dissolving 

 gelatin leaving the reticulum free. 



