THE UEINAEY TRACT. 779 



wavy degeneration of the red corpuscles had taken place. In the connective 

 tissue I have seen, though very rarely, clusters presenting the appearance 

 above described, which, perhaps, might be considered waxy degeneration of 

 extravasated blood. 



In the course of my researches I studied sixteen kidneys, five of which 

 were affected with chronic catarrhal nephritis, and eleven with chronic croup- 

 ous nephritis, and the conclusions arrived at were the following : 



First. Chronic catarrlial nephritis induces a new formation of connective tissue 

 throughout the kidney, which tissue is formed at the expense of the uriniferous 

 tubules. The surface of the kidney is marked by shallow depressions, or by gran- 

 ulations, more or less uniformly distributed. Chronic catarrhal nephritis invaria- 

 bly leads to a shrinkage of the kidney cirrhosis. 



Second. Chronic croupous nephritis may result in atrophy of circumscribed 

 portions of the kidney, with more or less destruction of the epithelial formations of 

 the affected parts. The surface of the kidney shows deep retractions, between 

 which the cortical substance remains comparatively unchanged. Chronic croupous 

 nephritis may also terminate in hypertrophy of the kidney, with an increase of its 

 bulk. This increase is due to an augmentation of the interstitial connective tissue, 

 which, as a rule, is accompanied by a narrowing of the tubules, and an almost 

 complete destruction and desquamation of the epithelia. 



Third. Suppurative nephritis may become chronic with an encapsulation of 

 the abscess, followed by a caseous metamorphosis of the pus. 



Fourth. Cystic degeneration may occur both in chronic catarrlial and chronic 

 croupous nephritis. Cysts are formed by a mucoid degeneration and liquefaction 

 of inflammatory corpuscles which are the products of former epithelial bodies. In 

 the early stages of cyst-formation the cavity is traversed by myxomatous tissue and 

 irregularly bounded by inflammatory corpuscles. In completed cysts a sero- 

 albuminous liquid is found, and the capsule is lined by a layer of flat endothelia. 

 Neither the capsule of the tuft nor the uriniferous tubules participate directly in 

 t lie formation of cysts. 



Fifth. Fatty degeneration occurs both in chronic catarrhal and chronic croupous 

 nephritis, reaching the highest degree, however, in the latter form of disease. It 

 consists of a transformation of bioplasson-granules into fat-granules both within 

 the epithelia and in the connective tissue. In high degrees of degenerative change 

 the fat-granules fuse together and form globules, which are often arranged in 

 clusters. 



Sixth. Waxy degeneration is a feature common to all forms of chronic nephritis. 

 If i tirades the epithelia and ultimately produces waxy casts. In many instances, 

 connective tissue, capillaries, tufts, and arteries are all involved in the process. 

 Atrophied tufts are almost invariably the seat of waxy degeneration. 



(2) The calices, the pelvis, and the ureter are constructed after 

 the manner of all mucous membranes. The most internal layer 

 is fibrous connective tissue, covered by stratified epithelia ; the 

 middle layers are composed of smooth muscle-fibers, and the 

 outermost layer is of loose, fibrous connective tissue. The mu- 

 cosa is made up of dense connective tissue, immediately below 

 the epithelial lining, and of delicate, loose connective tissue close 

 above the muscle-layers. The latter arrangement allows the for- 



