394 DISEASES OF THE KIDNEYS 



many of the glomeruli destroyed, degeneration of the epi- 

 thelium in the convoluted tubules, and the arteries are much 

 thickened. Microscopically the epithelium is found granular 

 and fatty; the tubules of the cortical substances are enlarged 

 and filled with tube casts. Hyaline changes are found in the 

 epithelial cells. The glomeruli are found enlarged, the cap- 

 sules are thicker than normal, and the capillaries show some 

 hyaline changes. The interstitial tissue is increased to some 

 extent.. 



(6) In chronic interstitial nephritis the kidneys are small, 

 contracted, and may be reduced to nearly one-half their 

 normal size. The capsule of the kidney is thickened, very 

 much adherent, and when stripped off carries with it some 

 of the cortical substance. Small cysts are often found on 

 the surface. On cut section the kidney is found reddish or 

 dark red in color. The cortex is very thin. The surface of 

 the kidney is uneven with numerous small projections. 

 Sometimes the kidneys are lobulated, the consistency is hard, 

 and the general texture almost semicartilaginous. The inter- 

 stitial connective tissue is far in excess of the parenchy- 

 matous structure. 



Microscopically there is noted a great increase in the 

 connective tissue, a degeneration and atrophy of the secreting 

 structures, both glomerular and tubal. The increase in the 

 fibrous elements is widely distributed throughout the kidney, 

 although in most cases found more extensively in the cor- 

 tical portion. The glomerular changes are found marked, 

 numbers of them being completely degenerated into hyaline 

 substances. The tubules show changes in the epithelium, in 

 some instances greatly atrophied, in others the epithelium 

 has entirely disappeared. 



The bloodvessels (arteries) in the advanced cases show 

 advanced sclerosis. The changes take place in the entire 

 vessel wall. In chronic nephritis we find in a great many 

 cases in dogs organic changes in the heart (hypertrophy) . 



Symptoms.— This condition does not present very definite 

 symptoms until the disease is quite well advanced. The first 

 symptoms noted are those of a general nature, such as par- 

 tial or complete loss of appetite, weakness, fatigue, etc. 



