THE URINE 139 



present it is impossible to distinguish the one from the other, 

 either in a hanging-drop or in stained films. 



If it is necessary to know whether B. coli or B. typhosus is 

 present along with Proteus vulgaris in an ammoniacal urine, the 

 simplest method is to plate out some of the urine on gelatin 

 (see p. 12), making several plates with different dilutions; as a 

 rule, a minute trace of the urine is all that is necessary. Typhoid 

 and coli form small, semi-translucent, greyish colonies which do 

 not tend to spread very much, whilst proteus forms small grey 

 colonies which form radiating branches and which liquefy the 

 gelatin, forming a saucer-like excavation with a little white mass 

 of growth in the centre. 



Streptococci occur occasionally as independent causes of pyelitis 

 or cystitis, and in these cases I believe the prognoses to be some- 

 what worse than in the other forms. 



Staphylococci usually occur as a secondary infection of other 

 forms of cystitis. The M. urea is a frequent cause of ammoniacal 

 decomposition of the urine, and is often mistaken for a staphylo- 

 coccus ; the two are indistinguishable under the microscope, but 

 staphylococci liquefy gelatin rapidly and M. urea does so slowly. 

 Their separation is of no clinical importance in these cases. 



The M. urea appears to be identical with the common skin- 

 coccus, which is the most common and characteristic organism 

 of the epidermis. It is a coccus which very frequently occurs as 

 a contamination in cultures, and, as a consequence, has been 

 accused of causing an abundance of diseases, including cancer. 



Gonococci. — When these are found in the urine it is necessary 

 to consider whether they come from the bladder or urethra. To 

 do so it usually suffices to see whether they occur in all parts of 

 the urine, and not simply in the first portions, which wash the 

 pus from the urethra. 



A caution is necessary in the diagnosis of gonorrhoeal cystitis, 

 as some cases of inflammation of the bladder (with acid urine) are 

 due to an organism closely resembling the gonococcus, but a little 

 larger and more variable in size : I believe it to be M. catarrhalis. 

 In cases where gonorrhoeal cystitis is suspected make a culture 

 on ordinary agar or on blood-serum. The diplococcus in question 

 grows readily, the gonococcus does not. 



Typhoid Bacilli. — These are rare causes of cystitis, but are 

 commonly found in the urine during and after an attack of typhoid 

 fever. When they produce cystitis the urine remains acid. 



