THE URINARY ORGANS. 



623 



commonly the pyogenic cocci, which have been brought through the 

 blood-vessels from a remote infective focus, as iu ulcerative endocarditis, 

 septic phlebitis, etc. embolic infection. Or, on the other hand, the bac- 

 terial excitant may be transmitted to the kidneys through the urinary 

 passages ascending infection. 



Traumatic lesions of the kidney may lead to suppurative nephritis 

 either through direct infection of the wound or by the establishment of 

 local vulnerability (see footnote, page 163) to the action of bacteria which 

 may later gain access to the injured tissue through the circulation. 

 After infected wounds or injuries of the kidney, large abscesses may 

 develop, or nearly the whole organ may be converted into a mass of pus, 

 blood, and disintegrated tissue. 



In the embolic type of suppurative nephritis, small abscesses are formed 

 most frequently in the cortex. Whgrft ba.pt piri a. lodge and grow in the 



FIG. 884. ScpprRATiYE NEPHRITIS. 

 Developed from infection by way of the urinary passages (so-called "surgical kidney"). 



tissue there is at first circumscribed hypersemia or haemorrhage and 

 necrosis, with subsequent gathering of leucocytes and finally the disin- 

 tSgration of tissue and the formation of abscess._ Such kidneys present 

 to the naked eye on section small spots or in the medulla streaks which 

 are red or gray or yellow, depending upon the degree of advancement of 

 the lesion. In such areas the bacteria may be readily demonstrated, 

 sometimes in early stages in dense masses in the capillaries and other 

 smaller vessels, or later scattered through the necrotic and disintegrat- 

 ing tissue (Fig. 96, page 205). Embolic abscesses are commonly devel- 

 oped in both kidneys and by extensive coalescence may give rise to large 



