SYSTEMATIC AND DESCKgJUf GH^A 243 



increase further by subdivision, and a jelly-like 

 membrane develops around them. Masses of cocci 

 exist in the form of irregular or roundish lumps. 

 Cultivations, after twenty-four hours, consist exclu- 

 sively of rods ; after forty-eight hours, of cocci 

 chains ; and in fourteen days, of zooglcea ; the cocci 

 transplanted into fresh nourishing solution again 

 grow into rods. These observations point to the 

 existence of a pleomorphic species, Bacterium 

 urea, and the former nomenclature Micrococcus 

 urea must be regarded as untenable. They are 

 aerobic ; occurring in urine they set up ammo- 

 niacal fermentation, converting urea into carbonate 

 of ammonia.* Rods, 2 p, long and i p, wide, have 

 been isolated from stale urine (Bacillus urece, Leube), 

 which also most energetically cause the ammoniacal 

 fermentation of urine. 



Bacterium aceti. Cocci, short rods, long rods, 

 leptothrix-forms, and zooglcea. Cocci and short 

 rods may occur in the same thread. The long 

 rods and threads may develop irregular swellings, 

 so-called involution-forms, which have a thickened 

 membrane and a grey colour. The effect of the 

 action of this microbe is to oxidise alcohol in wine 

 and other fruit juices into vinegar. The masses of 

 zooglcea united together form a membranous layer 

 which must not be mistaken for the pellicle formed 

 by Saccharomyces mycoderma. The latter prepares the 

 medium for the action of the Bacterium aceti. 



* Zopf, Die Sfaltyiize. 1885. 



