CATARRH OF THE BLADDER 417 



resistance of the mucous membrane of the bladder, allowing 

 infection to take place. 



(b) Infection may gain entrance to the bladder from the 

 blood. In some of the infectious diseases, as distemper in 

 the dog and cat, the bacteria are carried to the mucosa of 

 the bladder by the blood stream. In digestive disturbances 

 (constipation, etc.) the organisms which accumulate in the 

 bowels enter the blood stream and are eliminated through 

 the urinary passages, often leading to an acute cystitis. 

 The colon bacteria and others more or less closely related 

 are the chief offenders. 



(c) The infection may spread from the peritoneum, either 

 from acute or chronic peritonitis, producing in some cases 

 simply a pericystitis, and in others an involvement of the 

 entire bladder wall. 



2. Irritating agents in the form of chemicals, or drugs, 

 when eliminated in large quantities, frequently will produce 

 cystitis. Cantharides, turpentine, balsams, and coal tar 

 compounds given internally will produce it; external applica- 

 tions of easily diffusible substances will, by absorption have 

 the same effect, especially when applied over extensive areas. 



3. Sudden change in temperature, cold (chills) , disturbs the 

 general circulation, and may lead to congestion of the bladder. 

 Extreme cold affecting the body temperature might induce 

 extensive inflammation of the organ. 



4. Calculi and other foreign material often produce chronic 

 cystitis by the constant irritation they keep up. 



Pathology.— In the early stages of acute cystitis, the mucous 

 membrane will be found reddened, congested, much swollen, 

 and here and there small hemorrhages will be noted. There 

 is usually considerable thick, viscid mucus covering the 

 membrane, or there may be an admixture of pus. The 

 purulent exudate often covers the entire membrane. In the 

 later stages of the disease the mucosa is covered by a croupous 

 or diphtheritic, yellowish membrane. Abscesses of various 

 size may exist between the mucosa and the muscular walls. 

 Erosions and ulcerations on the membrane are often the 

 result of irritating materials. 



In the chronic form the pathological changes are principally 



