170 DISEASES OF THE URINARY AND SEXUAL APPARATUS. 



ing mass in the region of the kidney. When there is double 

 hydronephrosis the urine is suppressed and symptoms of ursemia 

 show very quickly. The only condition where the disease can be 

 treated is when it is caused by obstruction of the uretlira. 



Nephritic Stones. 

 [Nephrolithiasis.) 



Nephritic stones are formed iu the pelvis of the kidney and 

 range from the size of a mustard-seed to that of a pea. (Meguin 

 found two stones weighing six and seven grammes each in the 

 pelvis of a dog.) They are irregular, watery, yellowish or yel- 

 lowish-brown in color. In rare cases they become very large and 

 fill up the pelvis or greatly distend it. They are the shape of the 

 pelvis, and on section they are found to be in layers, and consist of 

 phosphoric acid, carbonic acid, triple phosphate, and uric acid. 



The formation of these collections is not thoroughly understood, 

 but they are probably formed by a small piece of epithelium or 

 mass of cells becoming fastened together, and the salts are deposited 

 on this medium in successive layers, and iinally a large mass is 

 formed. 



DISEASES OP THE BLADDER. 



Catarrh, of the Bladder. 

 ( Oyditis.) 



Etiology. Catarrh of the bladder is generally caused by cer- 

 tain mechanical or chemical influences or by microbes which find 

 their way into it as a result of certain infectious diseases, and are 

 eliminated by the kidneys or by certain chemical irritants, such as 

 oil of turpentine, cantharides, carbolic acid, and also foreign bodies. 

 These irritate the mucous membrane. Septic instruments, such as 

 catheters, when introduced into the bladder, may set up an irrita- 

 tion, and also by the extension of an irritation from the urinary 

 ducts, the pelvis of the kidney, from the uterus, and from reten- 

 tion of the uriue, caused by stones in the urethra, from hypertrophy 

 of the prostate. The last two are the most frequent causes of 

 cystitis. Where the urine becomes very alkaline from the excess 



