INFLAMMATION 



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enters and involves the bloodvessels. The softening of tissue 

 into pus is called suppuration, which may be defined as the 

 destruction of tissues and cells by bacteria and their products. 

 Pus under the microscope is composed of white blood cells, 

 particularly the so-called polynuclear leukocytes, micro- 

 organisms, some of which are free, others englobed by phago- 

 cytes, partly or wholly destroyed tissue, and, at least early 



FIG. 25. Secondary infection of a glomerulus of kidney by the Staphylo- 

 coccus aureus in a case of ulcerative endocarditis. The cocci (stained doubly) 

 are seen plugging the capillaries and also lying free. X 300. (Muir and 

 Ritchie.) 



in inflammation, a delicate meshwork of coagulum called 

 fibrin; the last is dissolved shortly as the suppuration pro- 

 ceeds. There is also some turbid fluid. 



The fluid and cells which appear in inflammation are 



collectively called an exudate. This may be of several forms; 



it may be true pus; it may be a thin, watery fluid in which 



are floating shreds of a gray, friable character called lymph, 



6 



