THE PATHS OF PYOGENIC INFECTION. 183 



entrance to the blood from a local lesion, and settling in a 

 favourable nidus or a damaged tissue, the original path of 

 infection often being obscure ; (^) by a septic phlebitis with 

 suppurative softening of the thrombus and resulting embol- 

 ism ; and we may add (<r) by a direct extension along a 

 vein, producing a spreading thrombosis and suppuration 



FIG. 52. Secondary infection of a glomerulus of kidney by the 

 staphylococcus aureus, 1 in a case of ulcerative endocarditis. The cocci 

 (stained darkly) are seen plugging the capillaries and also lying free. The 

 glomerulus is much swollen, infiltrated by leucocytes, and partly necrosed. 



Paraffin section; stained by Gram's method and Bismarck-brown, x 300. 



within the vein. In this way suppuration may spread along 

 the portal vein to the liver from a lesion in the alimentary 

 canal, the condition being known as pyelo-phlebitis sup- 

 purativa. 



1 This organism was obtained in pure culture from the kidney. 



