626 



THE URINARY ORGANS. 



The Tubules. The lesions of the tubules of the kidney in the early 

 phases of acute nephritis are largely degenerative ; the epithelium, es- 

 pecially of the convoluted tubules, is swollen and coarsely granular (Fig. 

 380), or it may contain few or many fat droplets (Fig. 381) albuminous 

 and fatty degeneration. The epithelium may become necrotic and may 

 disintegrate or peel off over larger or smaller areas. Thus the lumina of 

 the tubules may contain fragments of epithelium or detritus mingled with 

 albuminous fluid serum red blood cells and leucocytes, or hyaline or 

 other forms of casts (Fig. 379). Eed blood cells may be extravasated 

 in considerable numbers and collect in the tubules or pass on with the 



FIG. 387. ACUTE DIFHTSE NEPHRITIS. 



Showing proliferation of cells on the tuft and lining the capsule of the glomerulus and the formation of new 

 interstitial tissue with large polyhedral cells glomerular and interstitial type. 



exn dates. The casts and other exudates may be present in the cortex or 

 in the collecting tubes of the kidney. 



The Interstitial Tissue. This in early phases of acute nephritis may 

 be oadematous or it may be more or less infiltrated with leucocytes or 

 fibrinous exudate. Patches of new-formed small spheroidal cells, or 

 larger cells with conspicuous excentric nuclei may be present either in 

 the vicinity of the glomeruli (Fig. 387) or near the interlobular veins, 

 or a general thickening of the interstitial tissue may occur even very 

 early in some forms of acute diffuse nephritis, particularly in those fol- 

 lowing scarlatina and diphtheria. 



We have thus seen that in the early phases of an acute inflammation 



