THE SPLEEN AND THYMUS. 403 



WOUNDS, RUPTURE, AND HEMORRHAGE. 



Wounds of the spleen are usually accompanied by extensive haemor- 

 rhage and are commonly fatal. Death usually occurs as the result of 

 this haemorrhage, but it may be due to secondary inflammatory changes. 

 Healing and recovery may, however, occur. 



Rupture of the spleen may be traumatic or spontaneous. In the 

 former case it may be due to direct violence in the region of the organ 

 or to injury to the thorax, falls, etc. In certain diseased conditions the 

 spleen is more liable to rupture than when it is normal. The rupture 

 usually involves not only the capsule, but a more or less considerable 

 portion of the parenchyma, and of course leads to haemorrhage. Spon- 

 taneous rupture is rare, but may occur in excessive enlargement of the 

 organ, as in typhoid fever, malaria, etc. see below or as the result of 

 abscess. 



Haemorrhage. Aside from the extensive haemorrhages from injury and 

 rupture, the spleen may be the seat of small circumscribed haemorrhages 

 in various infectious diseases, although, owing to the peculiar distribu- 

 tion of the blood, it is often very difficult to distinguish between a mod- 

 erate interstitial haemorrhage and hyperaeinia. Sacculated aneurism of 

 the splenic artery has been reported. 



ATROPHY. 



Atrophy of the spleen may occur in old age ; as a result of prolonged 

 cachexiae, and in connection with profound and persistent anaemia; or, 

 more rarely, from unknown causes. The capsule may be wrinkled and 

 thickened, the color pale, the trabeculae prominent, the consistence in- 

 creased. The change is largely in the pulp, whose parenchyma cells 

 are decreased in number. 



DEGENERATION. 



Amyloid Degeneration. This may affect the glomeruli or the pulp 

 tissue, or both together. When confined to the glomeruli the spleen may 

 or may not be enlarged, and the cut surface is more or less abundantly 

 sprinkled with round or elongated, translucent bodies resembling consid- 

 erably in general appearance the grains of boiled sago. These are the 

 waxy glomeruli. Such a spleen is often called "sago spleen" (Fig. 208). 

 Microscopical examination shows that the degeneration is confined to the 

 walls of the arteries, capillaries, and reticulum of the glomeruli, with 

 atrophy and often finally total disappearance of the lymphoid cells. 



In other cases, either with or without involvement of the glomeruli, 

 there is waxy degeneration of the blood-vessels and reticulum of the 

 pulp, which may occur in patches or be general and more or less ex- 

 cessive. If the alteration is general and considerable the spleen is en- 

 larged, its edges are rounded, its consistence is increased. On section it 



