PELVIS OF THE KIDNEY. 415 



to interfere with parturition. Dermoid cysts are also found ; 

 echinococcic cysts are of occasional occurrence. 



PELVIS OF THE KIDNEY. 



In inflammation of the pelvis of the kidney pyelitis and 

 the associated lesions in the kidney itself, infection takes place 

 most frequently by way of the ureter, in connection with 

 urethral stricture, enlarged prostate, vesical calculus, and 

 cystitis. Though pyelitis may occasionally occur in the course 

 of infectious diseases and in non-infectious cases, for example, 

 as the result of the mechanical irritation produced by the pres- 

 ence of calculi, calculous pyelitis ; yet in the majority of 

 cases it is a septic or suppurative inflammation produced by 

 micro-organisms. Sooner or later there generally follows a 

 suppurative inflammation of the kidney itself pyelo-nephritis. 



FIG. 192. 



Hydronephrosis with granular atrophy of the kidney. The other kidney showed a 

 marked compensatory hypertrophy (Virchow). 



In pyelo-nephritis the kidney is swollen, soft, and friable, 

 its surface dotted with small yellow elevations which contain 

 pus. In size and number these abscesses may vary greatly. 

 They may be few and confined mainly to the cortex, or the 

 whole kidney may be fairly riddled with larger confluent ab- 

 scesses, communicating with the pelvis of the kidney, the 

 whole organ in some instances being converted into a large 

 pus-sac pyo-nephrosi*. When obstruction of the ureter causes 



