The Blood-Glands, 



103. The Spleen. 



Structure. The spleen is covered by the peritoneum, except at the 

 hilus. Under this SEROUS covering there is a tough thick elastic 

 fibrous CAPSULE, which closely invests the organ and gives a covering 

 to the vessels which enter or leave it at the hilus, so that fibrous tissue 

 is carried into the organ along the course of the vessels. [The capsule 

 cannot be separated without tearing the splenic pulp.] Numerous 

 TRABECUL^E pass into the spleen from the deep surface of the capsule. 

 These trabeculae branch and anastomose so as to produce a net-work 

 or sustentacular tissue, which is continuous with the connective tissue, 

 prolonged inwards and surrounding the blood-vessels (Fig. 88). Thus, 

 the connective tissue in the spleen, as in other viscera, is continuous 



Fig. 88. 



Trabeculse of the spleen of a cat with the splenic pulp 

 washed out a, trabecula ; b, vein. 



Fig. 89. 



Spleen of a cat injected 

 with gelatine, show- 

 ing the adenoid re- 

 ticulum. 



throughout the organ. In this way an irregular dense net-work is 

 formed, comparable to the meshes of a bath-sponge. [This net-work is 

 easily demonstrated by washing out the pulp lying in its meshes by 

 means of a stream of water, when a beautiful soft semi-elastic net-work 

 of rounded and flattened threads is obtained.] 



The Capsule is composed of interlacing bundles of connective tissue 



