THE SPLEEN. 137 



section, to the naked eye, a fibrous envelope the 

 capsule, from which septa and trabeculae pass into 

 the organ, enclosing irregular spaces. Here also we 

 find the spaces between the septa filled with a soft 

 substance presenting two distinct modes of arrange- 

 ment ; we find first, irregularly scattered through the 

 organ, small grayish globular or elongated struc- 

 tures, called Malpighian bodies, or nodules ; and, sec- 

 ond, between these, filling up the remaining space 

 between the trabeculae, a soft red tissue called the 

 pulp. 



Finally, we find blood-vessels entering the organ 

 at the hilus. We have, then, in studying the 

 spleen, to consider the connective-tissue capsule and 

 trabeculce, the nodules, the pulp, and the blood- 

 vessels. 



The capsule of the spleen consists of a dense en- 

 velope of interlacing connective-tissue fibres with 

 flattened cells, with a large number of fine elastic 

 fibres and a few smooth muscle-cells. It is covered 

 by a layer of endothelial cells similar to those of the 

 general peritoneal surface. At the hilus it passes 

 inward, forming a sheath for the large vessels, and 

 joins a complicated system of septa and trabeculce, 

 which, proceeding inward from all parts of the cap- 

 sule, form a multitude of irregular communicating 

 spaces in which the nodules and splenic pulp lie. 

 These trabeculae and septa are made up of the same 

 elements as the capsule, and in size and abundance 



