THE UEINAEY TRACT. 



Ill 



In the connective tissue fat-granules are often observed in the basis-sub- 

 stance, thus proving that the basis-substance is pervaded by living matter. 

 In high degrees of fatty metamorphosis, which are observed in cirrhotic as 

 well as in atrophied and hypertrophied kidneys after chronic croupous 

 nephritis, the fat-granules coalesce and form globules which to a great 

 extent replace the epithelia of the tubules. Large fat-globules are also 

 found in the interstitial connective tissue, which is under these circumstances 

 always increased in bulk. (See Fig. 354.) 



Fatty casts, in all probability, originate from a disintegration of the endo- 

 thelia, which had previously undergone a high degree of fatty change. In the 

 same way can be explained the presence of the large amount of fat-granules 

 and globules sometimes observed in the urine. This condition is always a 

 satisfactory proof that a high degree of fatty degeneration has taken place in 

 the kidneys. 



Waxy Degeneration. The epithelia of the tubules which have, in a measure, 

 escaped the inflammatory action, may become the seat of waxy degeneration, 

 when a similar condition has reached an advanced stage throughout the 



FIG. 354. FATTY DEGENERATION OF THE KIDNEY IN CHRONIC 

 CROUPOUS NEPHRITIS. 



E, tubular epithelia, containing granules and globules of fat; F, fat-globules in the 

 widened interstitial connective tissue ; #, capillary blood-vessel. Magnified 600 diameters. 



kidney-tissue. These epithelia sometimes assume the appearance of large, 

 glistening bodies projecting irregularly toward the center of the caliber of 

 the tube. When desquamated they are seen in the urine as more or less shin- 

 ing, homogeneous bodies, and readily recognized as waxy. 



In chronic croupous nephritis, waxy casts are sometimes observed studded 

 with waxy epithelia, or with granules, producing the epithelial or granular 

 waxy casts. The formations of waxy casts in the tubules may be easily 

 traced from the epithelia, which are changed into waxy globules, in part 

 homogeneous and in part granular, and which by coalescence evidently form 

 waxy casts. Around these casts a wreath of endothelia, also in waxy degen- 

 eration, may be recognized. (See Fig. 355.) 



