The nitroso-bacterium inoculated into sterile urine does not produce nitrites. If, however, urine be added to an active culture of this microorganism nitrites are rapidly developed.

A nitroso-bacterium culture developed in bulk in peat and chalk can be used as a urinal. After passing through this urinal all ammonia in urine appears to have been converted into ammonium nitrite and nitrate. No odour is noticeable when left to evaporate at either 37° C. or at room temperature.

Urine rendered ammoniacal before use and then sterilised is also a good medium for the growth of the nitroso-bacterium.

The nitroso-bacterium is difficult to isolate because (1) when colonies are developed on a dilution plate, sufficiently spaced to allow of certainty in subculture, nitrification only rarely takes place in the sub-culture, and when it does take place some months are required for the production of a measurable amount of nitrite, and (2) the nitroso-bacterium usually grows in association with some other more rapidly growing species. The colonies of this other microorganism often appear to be pure, but when growth has proceeded for some days individual colonies of the nitroso-bacterium may appear in a certain percentage of the plates.