THE URIXARY ORGANS. 



621 



various cachexise ; in acute and chronic forms of kidney disease, and in 

 poisoning by phosphorus, arsenic, etc. 



The degeneration may be diffuse and widespread or it may occur in 

 patches. If diffuse, the cortex in which it is most marked is usually 

 more or less thickened, opaque, and yellowish ; if in patches, there are 

 opaque yellow streaks or spots in the cortex. But these appearances are 

 often obscured by various other lesions. If the degeneration be moder- 

 ate in degree, there are larger and smaller fat droplets, usually most 

 abundant in the basal portion of the epithelium of the convoluted tubules 

 (Fig. 381). In more marked degeneration, the cells of the convoluted 



FIG. 382. AMYLOID DEGENERATION OF TUFT CAPILLARIES IN THE KIDNEY. 



a, The tuft is completely transformed into a waxy mass ; b, portions of tuft waxy ; c, tuft capillaries nor- 

 mal ; d, convoluted tubule with disintegrating epithelium. 



tubules may be filled with fat droplets and may peel off, or they may 

 disintegrate, setting the fat free in the lumen of the tubules. The de- 

 generation may involve the tuft and capsule epithelium as well as that 

 of the collecting tubes, and fat droplets may be found free or in cells in 

 the interstitial tissue. 



Amyloid Degeneration, This is usually associated with, amyloid de- 

 generation elsewhere in the body and commonly occurs in kidneys which 

 are already the seat of various forms of chronic lesion. Usually the 

 kidney is enlarged, the section is shining or translucent, the cortex is 

 thick and pale, the glomeruli are often unusually plain. The capillaries 

 of the tufts (Fig. 382) and the vasa recta are most often involved. If the 

 kidney be otherwise altered, the gross and microscopic appearances vary. 



Glycogen Degeneration of the epithelium may take place in diabetes 



