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 ureas (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, 



