RETICULAR. CONNECTIVE TISSUE 4!) 



passing from the ])la('enta to the fetus. A siniihirl\- api)eariiig tissue 

 may l)e fouud iu other refjions of the embryo ])rece(Iing the chffer- 

 entiation of the fihroelastic conneeti\-e tissue. 



RETICULAR CONNECTIVE TISSUE. 



This widely (Hstrihuted tissue is not easily demonstrated in 

 routine ])reparations. It ean l)e demonstrated assoeiated with 

 secretory epithelial organizations of glands and in the framework 

 of lymph organs. The cells resemble mesenchxine cells but are 

 larger, with a large, oval nucleus and long branching cytoi)lasmic 

 processes making contact, if not continuing with adjoining cells. 

 (Fig. 27.) Associated with the cells are branching fibers which 

 have an affinity for siher salts, so that they are called argyrophil 



Fig. 27. — Diagram of reticular tissue. 



fibers. By the use of silver salts which l)lacken them, these fibers 

 can be demonstrated as branching and anastomosing to form deli- 

 cate networks in all regions of the body. They are continuous with 

 the collagenous fibers of the loose fibroelastic connective tissue 

 which do not react in the same maimer to the sih'er salts. Embryo- 

 logically the argyrophil fibers appear before the collagenous type, 

 so that reticular tissue may be considered as the finer, less differ- 

 entiated continuations of the loose fil^roelastic connective tissue, 

 an intermediate condition l)etween it and mesenchyme. The wide 

 distribution of reticular tissue in close association with and transition 



4 



