756 



THE URINARY TRACT. 



chymatous and interstitial exudation, Virchow) is to "be regarded as an essen- 

 tial factor of the inflammatory changes, since partly mechanical changes and 

 partly nutritive disturbances are produced by it. 



In more severe and prolonged acute catarrhal inflammation the connective 

 tissue participates in what is called ' inflammatory infiltration," which leads 

 to hypertrophy (hyperplasia). It is a well-known fact that the changes in the 

 connective tissue are accompanied also by changes in the epithelium viz. : 

 at first, proliferation, then desquamation, and finally, hyperplasia of the epi- 

 thelium. 



Thus, the catarrhal inflammation in the kidney consists, in the beginning, 

 principally in changes of the epithelia, subsequently in changes of the con- 

 nective tissue. For this reason, a subdivision into epithelial changes (paren- 

 chymatous, Virchow) and connective tissue changes (interstitial, Virchow) is 

 not admissible. Catarrhal inflammation includes, with only gradual differ- 



FIG. 340. ACUTE CATARRHAL NEPHRITIS. INITIAL STAGE. 



C, convoluted tubule; N, ascending branch of narrow tubule; I, interstitial connective 

 tissue in rcdematous swelling; M, beginning of inflammatory infiltration. Magnified 500 

 diameters. 



ences, the desquamative, the interstitial, and also the parenchymatous form 

 of inflammation described by authors. 



I have studied acute catarrhal inflammation in the kidneys of a child six 

 years of age, dead of diphtheria, in which symptoms of ureemia had ensued 

 four or five days before death. The changes implicated principally the cortical 

 substance. (See Fig. 340.) 



Some capillaries are choked with red blood-corpuscles and dilated, others 

 hold a moderate amount of blood. Some blood-vessels contain, besides indis- 

 tinctly recognizable red blood-corpuscles, a finely granular material, which 

 corresponds, perhaps, to what authors call " micrococci." Since the inferences 



