CONNECTIVE TISSUE 



55 



similar. Less closely similar 'mucous' substances of the more compact 

 connective tissues are properly designated, mucoids. 



Reticular Tissue (Reticulum). Reticular tissue occurs as the 

 stroma of adenoid tissue in the lymphatic glands and other lymphoid or- 

 gans, and according to Mall (Johns Hopkins Hosp. Rep., 1896), is found 

 also in the membrana propria of the secreting tubules of the stomach, 

 intestine, kidney, testis, and thyroid, and in the marrow of bone and the 

 walls of the pulmonary air sacs. 



Like the other connective tis- 

 sues, reticular tissue consists of 

 cells, fibers, and ground substance ; 

 the latter, however, is no more 

 than a fluid tissue juice which, at 

 least in the lymphoid organs, is 

 identical with the lymph. The 

 fibers are extremely fine and are 

 arranged in slender bundles, which 

 freely anastomose to form a deli- 

 cate close-meshed reticulum. In- 

 dividual fibers can be readily dem- 

 onstrated in these bundles only 

 after the action of alkalies, diges- 

 lion by artificial gastric juice, or 

 >>y other methods of dissociation, 

 yet on careful examination indica- 

 tions of fibrillar structure can be 

 seen in the reticulum of fresh tis- 

 sue and in ordinary microscopical 



preparations. The chemical reactions of the reticular fibers are similar 

 to those of collagenous fibers except that the former are much less readily 

 digested by artificial gastric juice. 



Flattened connective tissue cells clasp the bundles of reticular fibers ; 

 they are mostly found at the intersections of the anastomosing bundles. 

 This fact was accountable for the former theory, which regarded reticu- 

 lar tissue as formed by the anastomosing branches of stellate cells. The 

 careful investigations of Carlier (Jour. Anat. and Physiol., 1895) and 

 others have shown the true nature of the lamellar cells and their under- 

 lying fiber bundles. 



The fibers of reticular tissue very closely resemble the collagenous 

 fibers of areolar tissue, but differ from them in having a clearer, more 



FIG. 63. RETICULUM OF A CERVICAL 

 LYMPH NODE OF MAN, FROM A THIN 

 SECTION FROM WHICH THE LYMPHATIC 

 CORPUSCLES HAD BEEN PARTIALLY 

 WASHED OUT. 



a, polynuclear lymphatic corpuscle; b, 

 large mononuclear cell; c, connective tis- 

 sue cells of the reticular tissue; d, fibrous 

 bundle of the reticulum; e, small mono- 

 nuclear lymphocyte. Hematein and 

 eosin. X 500. 



