408 THE SPLEEN AND THYMUS. 



those who have not thus suffered but have resided in malarial regions. 

 The enlarged spleen is often called "ague cake." Similar conditions, 

 though usually less marked, may occur in congenital and acquired syphi- 

 lis, from prolonged typhoid fever, and as a result of acute hyperplastic 

 splenitis from various causes, and also in leukaemia and pseudo-leukaemia. 



The gross appearance of the spleen in chronic iudurative splenitis 

 varies greatly, both in the size of the organ and in the appearance of the 

 section. The spleen may be enormously enlarged or it may be of about 

 normal size. It is usually, however, enlarged. The capsule is commonly 

 more or less thickened, frequently unevenly so. The consistence is 

 as a rule considerably increased, but this is not always the case. The 

 color and appearance of the cut surface present much variation. It may 

 be nearly normal or it may be grayish, or 

 dark brown, or nearly black. The color 

 may be uniform or the surface may be 

 mottled. The glomeruli may be scarcely 

 visible or very prominent ; the trabeculae 

 are in some cases nearly concealed by the 

 pulp ; in others they are large, prominent, 

 and abundant, so that the surface is crossed 

 in all directions by an interlacing network 

 of broader and narrower irregular bands, 

 between which the red or brown or black- 

 ish pulp lies. FIG. 210. CHROXTC IXDCRATITE SPLEN- 



Not less varied are the microscopical 

 appearances of the spleen under these con- 

 ditions. In one class of cases there is 

 more or less uniform hyperplasia of both pulp and interstitial tissue. 

 The parenchyma cells are increased in size and number ; there may be 

 swelling and proliferation of the lining cells of the cavernous veins (see 

 Fig. 210). The reticuluni of the pulp, as well as. that of the glomeruli, 

 and also the trabeculae, are thickened. In another class of cases the 

 thickening of the reticular and trabecular tissue, either uniformly or in 

 patches, is the prominent feature (Fig. 211), while the changes in the 

 pulp are rather secondary and atrophic. In both forms irregular pig- 

 mentation is frequent, the pigment particles being deposited either in the 

 cells of the pulp or glomeruli, or in the new-formed interstitial tissue (Fig. 

 212). Finally, there are all intermediate forms of induration between 

 those described, and the changes are by no means uniform in the same 

 organ. When these spleens are large they are liable to displacement. 



Syphilitic Splenitis. This lesion may present itself as an indurative 

 process due to the formation of new connective tissue, and present no dis- 

 tinct morphological characteristics. In rare cases, however, gummata 

 may be present in connection with the new fibrous tissue ; then the nature 

 of the lesion is evident. 



Tuberculous Splenitis. This lesion is usually secondary to tuberculous 

 inflammation in some other part of the body, or is the result of the gen- 



