§ IX.] Fermentation of urine. Nitrification. 85 



Micrococcus. Leube has recently demonstrated the existence 

 of four quite distinct species of Bacteria, in addition to the 

 Micrococcus just described, producing the same effects. 



Micrococcus Ureae, as' we learn from experiment, requires a 

 supply of oxygen for its vegetation. It can hardly therefore 

 be the cause of the alkalisation of the urine inside the bladder, 

 which has been observed in some affections of the bladder and 

 is supposed to be an effect of it, for the oxygen required is not 

 present. But numbers of small Bacteria are found in urine in 

 this diseased alkaline condition, and it must be assumed that 

 having found their way spontaneously or forcibly, as for instance 

 by means of the catheter, through the urethra into the bladder 

 they are the exciting cause of the decomposition in question. 

 It must accordingly be further assumed, that other species which 

 are anaerobiotic have the power of producing fermentation in 

 urine, or processes similar to it. Leube's species appear from 

 the accounts given of them not to be anaerobiotic. Miquel 

 (15, vol. for 1882) has in fact discovered a very delicate rod- 

 form occurring in dust, which he names Bacillus Ureae and 

 which vegetates anaerobiotically, converting urea into ammo- 

 nium carbonate in the same way as Micrococcus Ureae. 



We learn from van Tieghem that hippuric acid is converted 

 into benzoic acid and glycocol in the urine of herbivorous 

 animals by a Micrococcus, which is perhaps identical with 

 Micrococcus Ureae, but requires further investigation. 



2. In connection with the forms which change urine into 

 ammoniacal compounds, we may now turn to the consideration 

 of nitrification, the oxidation of compounds of ammonium into 

 nitrates, such as occurs on a large scale in the formation of 

 saltpetre, in so far as this also is due, according to the observa- 

 tions of Schlossing and Miintz (25, p. 708 ; 39), to the vegeta- 

 tion of small Bacteria. The phenomenon occurs in moist soil 

 penetrated by air and containing compounds of ammonium with 

 small quantities of organic matter and basic substances, for 

 example, salts of calcium. It may be induced artificially in 



