THE SPLEEN. 



583 



I. THE SPLEEN. 



The spleen consists of a serous and a fibrous coat, and a soft 

 parenchyma. 



1. The serous coat is the peritoneal investment, and adheres so 

 firmly to the fibrous coat that it can be dissected off* only in frag- 

 ments. 



2. The fibrous coat is composed of areolar tissue, and completely 

 invests the spleen, and, at the hilus, sends sheaths into the interior 

 around the vessels, like Glisson's capsule. 1 



3. The parenchyma is principally composed of (1,) the trabeculas, 

 inclosing (2,) the pulp, in which (3,) the Malpighian corpuscles are 

 found. 



1. The trabeculce are white, shining, flattened or cylindrical bars, 

 averaging T J^ to ^ of an inch, of are- 

 olar tissue, attached to the inner sur- 

 face of the fibrous coat, and sometimes 



to the outer surface of the sheath of 

 the vessels, and which unite to form a 

 network extending through the whole 

 organ. The interstices in it freely 

 communicate, and contain the red pulp 

 and the Malpighian corpuscles. Be- 

 sides the collagen ous and elastic ele- 

 ments, the trabeculse also contain many 

 peculiar spindle-shaped fibres 5 ^ to 

 4^ of an inch long, and 5 oVo of an 

 inch wide, with undulated ends and 

 prominent enlargements, containing 

 rounded nuclei. Kolliker at first mis- 

 took them for smooth muscular fibres. 

 Their nature is not fully understood. 

 They are sometimes found coiled up in 

 cell-like bodies. (Fig. 410.) 



2. The interspaces of the trabeculas are filled by the pulp, in which 

 the Malpighian bodies are lodged. The pulp is a soft, reddish sub- 

 stance, consisting of three elements: 1, the smallest bloodvessels ; 

 2, microscopic fibres and trabeculae: and 3, peculiar cells. The oc- 



Peculiar fibres from the pulp of the 

 human spleen. A. The same, free B. 

 One inclosed in a cell. Magnified 3oO 

 diameters. (Ktlliker.) 



1 In the ox, dog, pig, ass, and cat, it contains smooth muscular fibres also. 



