THE UBINABY ORGANS. 635 



grees of atrophy or complete destruction of the epithelium and the tu- 

 bules. Between these fibrous regions, little altered tubules may be pres- 

 ent or those with granular and fatty degeneration, exfoliation, and dis- 

 integration of the epithelium. Various forms of casts may be present in 

 the tubules ; the epithelium may be flattened with enlargement of the 

 lumen. The glomemli are variously altered ; thus there may be thicken- 

 ing of the capillary walls and of Bowman's capsule (Fig. 397), increase 

 and exfoliation of the tuft and capsular epithelium, or a more or less 

 complete conversion of the glomerulus into a knob of dense fibrous tissue. 



1 





FIG. 395. CHRONIC DIFFUSE NEPHRITIS ATROPHIED KIDNEY. 



The capsule is thickened and adherent, especially to the dense mass of flbrous tissue at the left of the 

 section in which the tubules are greatly atrophied. At the right the parenchyma is less atrophied, but here 

 the lumina of the tubules are dilated, the epithelium is degenerating and flattened. 



In advanced phases of the lesion the kidney may be very small ; then 

 a large part of the tissue is involved ; and while the atrophy is always 

 more marked in some places than in others, it is often difficult to find 

 any normal structural elements. 



Fibrous thickening of the walls of the arteries and veins of the kid- 

 neys is usual in this type of chronic diffuse nephritis (.Fig. 398). 

 Amyloid degeneration of the vessels is not infrequent. The heart is 

 often greatly hypertrophied and general arterio-sclerosis is common. 



Variations in Type in Chronic Diffuse Nephritis. There are many vari- 

 ants in the two types of chronic diffuse nephritis which we have briefly 

 described. It is possible to indicate in a general way morphological 

 appearances which are frequently present and more or less character- 

 istic of each of the variants when the kidney lesions occur in connection 



