THE AMMONIAOAL DECOMPOSITION OF URINE. 375 



twenty minutes on two successive days in the steam of boiling 

 water ; the tubes were then placed in an incubator, and after an 

 interval of three weeks were still found to be sterile without 

 the slightest trace of ammonia being present. 



Sterile neutral urine was prepared in the same way. 



In starting the cultivation of the organisms I adopted the 

 plan described by Dr. Klein at a recent meeting of the 

 Chemical Society. The fine end of a freshly made capillary 

 pipette was placed in the ammoniacal urine, and a little 

 allowed to ascend in the tube by capillarity ; a number of tubes 

 containing nutrient gelatine were then inoculated by passing 

 the pipette through the cotton-wool plug and allowing a drop- 

 let of the urine to pass out ; the tubes were then placed in 

 water having a temperature of about 40° for the purpose of 

 melting the gelatine ; they were then gently shaken so that 

 the droplet which had been introduced should be uniformly 

 distributed, the gelatiue being subsequently poured out, with 

 the usual precautions, into the lower of the two dishes used in 

 plate cultivations and allowed to reset. After this had oc- 

 curred, the glasses were placed on a glass plate, covered with 

 a Bell jar containing a piece of moist blotting paper and main- 

 tained at a temperature of 20° C. in an incubator. 



By these means after the introduction of the smallest droplet 

 a large number of organisms was obtained, and by the subse- 

 quent processes of " fractional cultivation '^ and " dilution " 

 these were isolated, and the tubes containing the acid and 

 neutral sterile urine inoculated with them with the view of 

 determining the particular organisms producing the ammo- 

 niacal change. 



By these methods T was able to isolate about twenty dif- 

 ferent organisms, both bacilli and micrococci, but after re- 

 peated experiments I only found one organism — ^a micrococcus 

 — able to decompose the urea into carbonate of ammonia. It 

 would be tedious and serve no useful purpose to describe each 

 of these organisms, and so I shall confine my remarks to a 

 description of that one which induces the desired change. 

 If a plate cultivation be made of this micrococcus, and kept 



