THE SPLEEN AND THYMUS. 



409 



eral infection in acute general niiliary tuberculosis. The tubercles may 

 be very numerous and still invisible to the naked eye, or they may be 

 just visible, or as large as a pin's head, and very thickly strewn through 



i 



FIG. 211. CHRONIC INTERSTITIAL SPLENITIS. 



a, Thickened capsule; b, thickened trabecule; c, dilated cavernous veins; (?, dense pulp tissue with 

 obliterated cavernous veins. 



the organ or sparsely scattered. In other cases the tubercles are larger, 

 sometimes as large as a pea, and they are then usually not numerous. 

 Microscopically they present the usual variety of structure, sometimes 

 as simple tubercle grauula, sometimes as conglomerate tubercles ; they 

 may consist simply of a collection of small spheroidal cells, or there may 

 be larger polyhedral cells and giant cells with a well-defined reticulum. 

 Cheesy degeneration occurs under the usual 

 conditions. Tubercle bacilli are usually pres- 

 ent, particularly in the more acute forms, 

 sometimes in small, sometimes in enormous 

 numbers. They seem to be especially abun- 

 dant in acute general miliary tuberculosis of 

 children. These tubercles may be formed in 

 the glomeruli, in the walls of the smaller 

 arteries, in the pulp tissue, and in the trabec- 

 ulse and capsule. Owing to the peculiar 

 character of the spleen tissue the earlier 

 stages are not readily recognized, since simple 

 collections of small spheroidal cells are not 

 distinctly outlined against the normal tissue. 



There is frequently a moderate swelling of the spleen, owing to hyper- 

 ?emia and hyperplasia of the parenchyma. 



Perisplenitis. ACUTE INFLAMMATION of the capsule of the spleen 

 may occur as a part of a general or localized peritonitis, or as a result 



FIG. 212. MALARIAL SPLEEN*. 



Showing thickening of the trabec- 

 ular network of the pulp, with pig- 

 mentation of the pulp cells. 



