SEC. 3. THE SPLEEN. 



469. The Structure of the Spleen. We may now pass on to 

 the consideration of the formation of the constituents of bile, a 

 matter which in dealing with the secretion of bile ( 256) we 

 postponed. Of these constituents the most important are the 

 " bile salts " on the one hand, and the bile pigment on the other. 

 We will take the latter first ; but since, as we have already said 

 ( 26), the bile pigment, bilirubin, appears to be derived from 

 hemoglobin, and since the spleen seems to be especially concerned 

 in the changes which haemoglobin undergoes in the body, we must 

 first turn to the structure of that organ. 



When a fresh spleen is cut across, the whole interior within 

 the well-defined coat or capsule presents the appearance of a dark 

 red spongy mass, traversed by irregularly disposed paler bands or 

 trabeculce, and mottled by the presence of white bodies about the 

 size of a pin's head, the Malpighian corpuscles, also irregularly 

 disposed. The whole organ is very soft, and, by squeezing or 

 otherwise, small portions of the red spongy mass can be isolated in 

 a semi-fluid pulpy condition, known as spleen-pulp. The redness 

 is obviously due to red blood corpuscles ; and it is clear, at the 

 outset, that the spleen possesses an unusually large supply of 

 blood, which moreover seems to be disposed in an unusual 

 manner. 



When by a stream of normal saline solution driven through 

 its vessels as much blood as is possible is .washed away from the 

 spleen, and the organ is subsequently hardened in the usual way, 

 preferably in a distended condition, sections reveal the following 

 features. The capsule consists of an outer layer of connective 

 tissue covered with epithelioid plates, forming the peritoneal coat, 

 and continuous with this an inner deeper layer, composed of 

 connective tissue with networks of elastic fibres and containing a 

 certain number of bundles of plain muscular tissue ; this deeper 

 layer of the capsule gives off rounded or flattened bundles of the 

 same nature as itself, which pass in all directions into the interior 

 of the organ, branching and anastomosing freely ; these are best 

 developed towards the side or hilus, where the branches of the 



