ENTRANCE AND SPREAD OF BACTERIA 215 



lining epithelium. In this way the kidneys and liver respectively 

 may be infected. Third, by the blood vessels : (a) by a few 

 organisms gaining 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 ; (b) by a septic phlebitis 

 with suppurative softening of the thrombus and resulting em- 

 bolism ; and we may add (c), by a direct extension along a vein, 



Fia. 52. — Secondary infection of a glomerulus of kidney by the 

 staphylococcus aureus, 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. 



producing a spreading thrombosis and suppuration 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 pylephlebitis suppurativa. 



Although many of the lesions produced by the bacteria 

 under consideration have already been mentioned, certain con- 

 ditions may be selected for further consideration on account of 

 their clinical importance or bacteriological interest. 



