624 THE URINARY ORGANS. 



abscesses. There is reason to believe that in certain forms of septicaemia 

 bacteria may secure a foothold in the tubules, not as emboli, but through 

 excretion. ' In such cases the suppurative foci may be at first limited 

 to the medulla. 



Ascending Infection. In suppurative nephritis associated with a sim- 

 ilar process in the ureter, bladder, etc., the medullary portion of the 

 kidney is usually earliest involved and then the elongated form of the 

 suppurative areas (Fig. 384) corresponds to the grouping of the tubules 

 in this region. 2 



Whatever the form in which it may manifest itself, suppurative in- 

 flammation of the kidney is commonly induced by some one or combi- 

 nation of the pyogenic micro-organisms which may lodge within it under 

 favorable conditions. Thus Streptococcus pyogenes, Staphylococcus py- 

 ogeiies, Bacillus coli comnmnis, Bacillus pyocyaneus, Bacillus proteus ; 

 the pueumococcus, the typhoid bacillus, and others, may be found in the 

 suppurative foci. Sometimes, however, especially in the more chronic 

 processes, micro-organisms are not demonstrable. 



ACUTE DIFFUSE NEPHRITIS. 



This process may occur in acute infectious diseases ; it is especially 

 common in scarlatina and not infrequent in diphtheria, typhoid fever, the 



exanthemata, malaria, and 

 in septicaemia due to vari- 

 ous bacterial excitants. 



Tne lesious of acute dif ' 

 f use ne P nritis var y greatly 

 iu extent > in degree, in the 

 relative involvement of one 

 or other renal structure, 

 as well as with the dura- 



FIG. 385.-AC.TE DIFFUSE NEPHRITIS. ^ ^ ^ 



Showing swelling of the cells covering the capillary tufts and 



lining Bowman's capsule. as in other forms of inflam- 



mation of the kidney, de- 

 generation is an important and often predominant factor in the mor- 

 phology of the lesions. 



We shall now consider those lesions which in varying degrees are 

 characteristic of an early phase of acute diffuse nephritis, such as fre- 

 quently occurs in the course of the acute infectious diseases. While 

 changes in the different structural components of the kidney may occur 

 simultaneously and are intimately related to each other, we shall study 

 first the lesions of the glomeruli, second those of the tubules, third those 

 of the interstitial tissue and its vessels. 



The Glomeruli. One of the early alterations in the tufts of the glom- 



1 For study of excretion of bacteria by kidney see Ascfi, Cbl. f. Kr. d. Ham- u. Sex.- 

 Org., Bd. xiii., 1902, pp. 249 and 324. Also reference pp. 163 and 626. 



For study of elimination of pigment by kidney, see Carter, Jour. Am. Med. Assn., 

 November 21st, 1903. 



2 For further details concerning suppurative nephritis consecutive to similar proc- 

 esses in adjacent organs see below. 



