THE SPLEEN AND THYMUS. 407 



of both. There are multinuclear cells ; cells resembling the ovoidal and 

 polyhedral cells of the pulp, but larger -and with evident division of the 

 nuclei. Cells resembling leucocytes may be present in large numbers, 

 and larger and smaller cells in a condition of fatty degeneration, or con- 

 taining pigment, are often seen. The elongated cells lining the cavernous 

 veins may be swollen or increased in number. Xot infrequently the larger 

 and smaller cells contain red blood cells or their fragments. In some 

 cases, particularly in scarlatina, hyperplasia of the glorneruli is a prom- 

 inent feature : in other cases, particularly in typhus and recurrent fevers, 

 the cells of the glomeruli undergo marked degenerative changes, so that 

 they may form small softened areas looking like little abscesses. Focal 

 necroses and areas of small-celled accumulation or cell proliferation are 

 common in typhoid fever and other infectious diseases (see page 201). 

 As the primary disease runs its course the swelling of the spleen sub- 

 sides, the capsule appears wrinkled, the color becomes lighter, and 

 sometimes the organ remains for a long time, or permanently, small and 

 soft. 



The lesions of the spleen are in many cases due to the presence of 

 micro-organisms which are usually present in the spleen in septicaemia, 

 or they may be due to soluble toxic substances in the blood. l 



Suppurative Splenitis (Splenic Abscess}. Small abscesses may be found 

 in the spleen as the result of minute infectious emboli, and these may 

 coalesce to form larger abscesses. Sometimes the entire -parenchyma is 

 converted into a soft, necrotic, purulent mass surrounded by the capsule. 

 It is rare for simple infarctions to result in abscess. Abscess of the 

 spleen may occur from the propagation of a suppurative inflammation to 

 the organ from adjacent parts; from periuephritic abscesses, ulcer and 

 carcinoma of the stomach, etc. They may open into the peritoneal cav- 

 ity, inducing fatal peritonitis, or, owing to an adhesive inflammation, 

 the opening may occur into the post-peritoneal tissue, into the pleural 

 cavity, lung, stomach, intestines, or it may open on the surface. On the 

 other hand, the contents of the abscess may dry, shrink, and become 

 encapsulated and calcified. Abscesses may occur in ulcerative endocar- 

 ditis, pyseniia, typhoid fever, and more rarely in intermittent fever, and 

 under a variety of other conditions. 



Chronic Indurative Splenitis (Chronic Splenic Tumor}. There maybe, 

 as we have already seen, a new formation of connective tissue in the 

 spleen as a result of chronic congestion or infarctions, or about abscesses. 

 But there is a more diifuse formation of connective tissue, usually in the 

 nature of an hyperplasia, which occurs under a variety of conditions, 

 and is now marked and extensive, and again comparatively ill -defined. 

 It is always associated with more or less extensive changes in the paren- 

 chyma. In its most marked form it is found in chronic malarial poison- 

 ing, and under these conditions it may be found not only in persons who 

 have suffered from repeated attacks of intermittent fever, but also in 



1 For a study of the role of the spleen in infections see Courmont and Duffau, 

 Arch, de Med. Exp., t. x., p. 431, 1898, bibl. 



