358 DISEASES OF THE URINARY APPARATUS. 



are filled with an inflammatory liquid, which is albuminous and 

 coagulates by ebulition, also by the action of alcohol, etc., and 

 forms a sickle-shaped zone surrounding the glomeruli ; the capil- 

 lary walls are hyaline and tumefied ; these canals may be throm- 

 bosed by white corpuscles or by epithelial cells undergoing pro- 

 liferation. The other parts of the kidney are but little or not at 

 all altered. 



2. Diffused acute nephritis. With the infiltration and thickéuing 

 of the interstitial connective tissue by a liquid fibrinous exudate 

 we observe compression of the vessels, tumefaction, softening, fatty 

 degeneration, desquamation of the epithelium of the urinary canal- 

 iculi, and the appearance within them of hyaline cylinders. The 

 glomeruli are intact. 



3. Nephritis circumscribed to small centres. It is characterized 

 by circumscribed cellular infiltration from the cortical substance 

 and from the neighborhood of the veins; the epithelium of the 

 glomeruli and of the uriniferous canaliculi is generally intact, but 

 hyaline cylinders may be formed inside of these. This form of 

 nephritis, which is the most frequent, is often accompanied by 

 circumscribed indurations, abscesses, cavities, and cicatricial spots. 



4. Purulent nephritis. This is the result of an intense cellular 

 infiltration in the neighborhood of the veins or in the glomerular 

 capsules ; it is recognized by the presence of purulent centres which 

 are rounded or stretched in bands and surrounded by a red zone. 

 It is developed after the penetration of micro-organisms into the 

 glomerular loops ; these become obstructed and necrotic ; the inflam- 

 mation starts at their periphery, and the neighboring epithelium 

 becomes desquamated. Under the name of '^embolic nephritis,'^ 

 Friedberger has described a case of this kind which was observed 

 in the horse. White corpuscles and micrococci sometimes pene- 

 trate in very large numbers into the inside of the uriniferous 

 canaliculi and completely obstruct them (see the case of bacterial 

 nephritis of the ox, related by Dammann). The small abscesses 

 thus formed may become confluent and constitute a large purulent 

 centre, and even transform the kidney into a true sac filled with 

 pus, an alteration which is observed quite frequently upon the 

 ox (see Purulent Nephritis). In man, in cases of diphtheria, we 

 find accumulations of micrococci in the uriniferous canaliculi 

 (Letzerich). 



The so-called " parenchymatous degeneration of the kidney is 



