410 THE SPLEEN AND THYMUS. 



of lesions of the spleen itself, such as infarctions, abscesses, and acute 

 hyperplastic inflammation. Under these conditions a fibrinous pellicle, 

 with more or less pus, may be formed on the surface of the organ. 

 CHRONIC INFLAMMATION, resulting in the production of new connective 

 tissue, either in patches or as a more or less general thickening of the 

 capsule, is of frequent occurrence. It may follow acute inflammation of 

 the capsule, or be a part of general or localized chronic peritonitis. It 

 is common in connection with chronic iudurative splenitis, and it may 

 occur from unknown causes. Sometimes the capsule is three or four 

 millimeters in thickness over a considerable area ; sometimes very small 

 nodular thickenings or papillary projections occur. As a result of this 

 process adhesions, sometimes very extensive, may form between the 

 spleen and adjacent parts. The thickened capsule is sometimes more 

 or less extensively calcified. 



CHRONIC ENDOTHELIAL HYPERPLASIA OF THE SPLEEN. 



("Primary Splenomegaly.") 



Bovaird has recently described a slowly progressive lesion developing 

 in early life in which the spleen was greatly enlarged and firm in text- 



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til; illiW 



lISlSllW ,,.a 



FIG. 213. CHRONIC ENDOTHELIAL HYPERPLASIA OF THE SPLEEN. 

 Showing increase in number and exfoliation of the endothelium of the cavernous veins. 



ure, presenting on section numerous irregular white or yellowish areas, 

 extending from the capsule into the substance of the organ. The splenic 

 and meseuteric lymph-nodes and the liver were enlarged. On microscopic 

 examination the spleen lesion was found to consist largely of an excessive 

 proliferation of the eudothelial cells of the pulp (Fig. 213), in part alone, 

 in part associated with fibrous hyperplasia. Similar endothelial hyper- 

 plasia occurred in the splenic and mesenteric lymph-nodes and in the 

 connective tissue of the liver. There was marked pigmentation of the 



