46 CONNECTIVE TISSUES 



even polymorphous. In the latter case it consists of two or more 

 lobules united by a chromatin filament. The amount of cytoplasm 

 which surrounds the nucleus is variable, but never very great. 



The lymphatic corpuscles* are so closely packed that it is 

 almost impossible to distinguish the fine lines 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 different organs and even in different portions of the 

 same organ. The denser accumulations of lymphoid corpuscles 

 may form either ovoid lymphatic nodules or follicles, or long dense 

 trabeculae, the lymphatic cords, which are surrounded by looser 

 portions of lymphoid tissue. 



Lymphatic corpuscles are frequently infiltrated into the con- 

 nective tissue of the mucous membranes, where they form irregular 



a 



FlG. 49. A LYMPHATIC NODE OF A DOG, SHOWING LYMPHATIC NODULES AND CORDS. 



The lymphatic corpuscles have been partially removed from the medulla, a, me- 

 dulla ; 6, cortex ; c, nodules in the cortex ; d, cords in the medulla ; e, a fibrous trabecula. 

 Hematein and eosin. Photo, x 20. 



collections, which may be termed diffuse lymphoid tissue, in con- 

 tradistinction to compact lymphoid tissue, which occurs in the lym- 

 phatic glands, tonsils, thymus, and spleen, and in Peyer's patches 

 and the solitary follicles of the intestinal tract. Diffuse lymphoid 

 tissue is found in the mucous membranes of (A) the respiratory 

 tract nose, naso-pharynx, larynx, trachea, and bronchi ; and (B) 

 the alimentary tract mouth, tongue, pharynx, esophagus, stom- 

 ach, and intestines. 



* For the several types of lymphatic corpuscles see Chapter X. 



