MICROBES, OR BACTERIA. 107 
This ferment is often found in wine, together with 
those of yeast and alcohol, and produces in it an in- 
cipient lactic fermentation. The predominance of one 
of these fermentations depends on the composition 
of the medium, which may be more or less adapted 
to them. A slightly alkaline medium is most suitable 
for the lactic microbe, while in a perfectly neutral 
medium only alcoholic fermentation will occur. 
We have already said that mare’s milk can be 
transformed into an alcoholic liquid called koumiss. 
-VI. THe AMMONIACAL FERMENTATION OF URINE. 
Shortly after its discharge, urine which is left to 
itself assumes an ammoniacal odour, This is due 
to the transformation of the urea (the nitrogenous 
principle of urine) into ammonia and carbonic acid, 
under the influence of a microbe which appears in 
the form of free globules, of articulated filaments 
(Torula), or of chaplets, resembling those of the lactic 
ferment. This microbe is found in the white deposit 
which collects at the bottom of vessels, and has been 
termed Micrococcus wree (Fig. 59). 
This ferment is conveyed through the air, like 
other microbes of fermentation. It does not exist in 
the bladder as long as the urine remains acid. Yet, 
in the rare cases in which urine has been found to be 
alkaline, immediately after its issue from the bladder, 
