166 ENTOZOA FOUND IN MAN. 



be formed by a cyst which possesses strong walls, 

 and is roughened, and of a yellowish colour upon its 

 internal surface. 



Hydatid cysts of the kidney may exist for a long 

 time without producing any organic lesions, but they 

 almost invariably terminate by the production of 

 inflammation and ulceration of the surrounding parts, 

 which are finally perforated ; sometimes they open 

 at the surface of the body, in the lumbar region, 

 and sometimes they form a communication with the 

 intestine ; they also occasionally penetrate the cavity 

 of the chest, and open into the bronchi. According 

 to the situation at which the cyst opens, the hydatids 

 are discharged tlirough a lumbar fistula, or are 

 expelled with the evacuations, or are expectorated 

 during the fits of coughing. 



More often, however, hydatid cysts of the kidney 

 contract adhesions with the walls of the pelvis of the 

 kidney, and open into its cavity. The smallest 

 hydatids, and pieces of the larger ones, together with 

 some of the serous or sero-purulent fluid contained 

 in the cyst, are then passed with the urine. When 

 this termination occurs, there is pain in the renal 

 region, and sometimes retention of urine, caused by 

 the obstruction which results from the entanglement 

 of the hydatids in the pelvis of the kidney, in the 

 ureter, or the urethra ; the ureter becomes, after a 

 time, considerably dilated. 



The hydatid cysts in the kidney which are still 

 unbroken do not ordinarily give rise to any compli- 

 cations or to any inconvenience, beyond that which is 

 attributable to their bidk. When they have opened 

 into the calices, or into the pelvis of the kidney, the 



