686 ORGANS OF DIGESTION. 



whole substance of the pulp, filling up the interspaces formed by the partitions of 

 the spleen, and lying in close contact with the walls of the capillary vessels, so as 

 to be readily acted upon by the nutrient fluid which permeates them. These 

 elements form a large part of the entire bulk of the spleen in well-nourished ani- 

 mals ; whilst they diminish in number, and occasionally are wanting, in starved 

 animals. The application of chemical tests shows that they are essentially a pro- 

 tein compound. 



The colored elements of the pulp consist of red blood-globules and of colored 

 corpuscles, either free, or included in cells. Sometimes, unchanged blood-disks 

 are seen included in a cell ; but more frequently the included blood-disks are 

 altered both in form and color. Besides these, numerous deep-red, or reddish- 

 yellow, or black corpuscles and crystals, either single or aggregated in masses, are 

 seen diffused throughout the pulp-substance ; these, in chemical composition, are 

 closely allied to the hasmatin of the blood. 



Malpighian Corpuscles. On examining the cut surface of a healthy spleen, a 

 number of small semi-opaque bodies, of gelatinous consistence, are seen dissemi- 

 nated throughout its substance ; these are the splenic or Malpighian corpuscles 



Fig. 348. The Malpighian Corpuscles, and their Relation with the Splenic Artery 



and its Branches. 



(fig. 348). They may be seen at all periods of life ; but they are more distinct 

 inearly life, than in adult life or old age ; and they are much smaller in man, than 

 in most mammalia. They are of a spherical or ovoid form, vary considerably 

 in size and number, and are of a semi-opaque whitish color. They are appended 

 to the sheaths of the smaller arteries and their branches, presenting a resemblance 

 to the buds of the moss rose. Each consists of a membranous capsule, composed 

 of fine pale fibres, which interlace in all directions. In man, the capsule is homo- 

 geneous in structure, and formed by a prolongation from the sheaths of the small 

 arteries to which the corpuscles are attached. The bloodvessels ramifying on 

 the surface of the corpuscles consist of the larger ramifications of the arteries to 

 which the sacculus is connected ; and also of a delicate capillary plexus, similar 

 to that surrounding the vesicles of other glands. These vesicles have also a 

 close relation with the veins (fig. 349). These vessels, which are of considerable 



