156 CLINICAL BACTERIOLOGY. 



The bacteria gain entrance into the urinary bladder 



1. Through unclean instruments employed in catheteri- 

 zation. 



2. By ascending through the urethra this is especially 

 the case in women. 



3. Through the intermediation of the kidneys ; some 

 bacteria are capable of passing through the renal filter; and 

 thus gain entrance with the urine into the bladder. 



Among influences favoring the development of cystitis 

 are cold, traumatism, and retention of urine. In addition 

 to the common exciting agents of suppuration other less 

 common microorganisms have been found in individual 

 cases of cystitis : the so-called micrococcus albicans am- 

 plus, the diplococcus subflavus, the proteus, and others. 

 These bacteria are, however, not pathogenic in themselves, 

 and probably acquire importance only in mixed infection. 

 The proteus causes putrid decomposition of the urine. 



Bacteriologic Diagnosis. Catheterization is practised 

 by means of a catheter sterilized by boiling, the urine being 

 received into a sterile vessel. Men are permitted simply to 

 pass urine spontaneously, the last portion evacuated being 

 kept for examination, and the orifice of the urethra having 

 previously been thoroughly cleansed. From the urine plate- 

 cultures are made. 



Experiments on Animals. By injecting pyogenic cocci 

 into the bladder it is possible to induce cystitis in male ani- 

 mals with certainty, if the escape of urine is prevented for 

 from twelve to twenty-four hours by ligation of the penis. 



Ammoniacal Fermentation of Urine. The bacterium 

 coli possesses, in only slight degree, the faculty of causing 

 decomposition of urine. Ammoniacal fermentation results 

 from the action of individual varieties of the bacterium coli 

 in the presence of a feebly acid, or an alkaline, reaction of 

 the urine. Other varieties of the bacterium coli are incap- 

 able of causing decomposition of urine. Ammoniacal 

 cystitis, however, develops in the presence of the staphy- 

 lococcus pyogenes or the proteus, whether in pure culture 

 or in mixed infection with the coli commune. 



Pneumaturia. In some cases of cystitis, especially 

 with coincident presence of sugar in the urine, but also in 

 the absence of glycosuria, the formation of gas may take 

 place in the bladder. The urine under such circumstances 

 is evacuated with an audible sound (pneumaturia). This 



