2o6 RELATIONSHIPS OF THE COCCACE^ 



Whether the organisms which bring about the am- 

 moniacal fermentation of stale urine, M. urea and M. 

 urea liquefacienSj belong to this genus, and whether they 

 are distinct species or not, can only be determined by 

 comparative study. At present we know neither the 

 other properties of the urine-fermenting forms, nor the 

 extent to which the power of fermenting urine occurs 

 among other well-recognized cocci. Little has been done 

 in recent years in regard to this biochemical property. 

 Comparative studies of various cocci, using perhaps a 

 solution of urea of known composition, rather than urine 

 itself, might well yield results of systematic and theoret- 

 ical importance. In the absence of such investigations, 

 the question of the systematic significance of the urine- 

 fermenting power must be left in abeyance. 



Several forms of white cocci belonging to this genus 

 have been characterized by the fact that they produce 

 peculiar star-like or moss-like colonies on gelatin. Among 

 these are M. radiatus (of the general type of Alb. pyo genes), 

 M. cirrhiformis , Migula, M. polypus, Migula, and M. 

 stellatus, Frankland (allied to Alb. candidus). It is very 

 doubtful, as pointed out in Chapter III, whether differ- 

 ences of this sort are of sufficient systematic importance 

 to warrant their perpetuation in specific names. 



Catterina (1903) has described an organism, apparently 

 belonging to the genus Albococcus, which resembled the 

 last named forms in its production of moss-like colonies, 

 but was actively motile and possessed clearly stainable 



