THE CLASSIFICATION OF BACTERIA 1 15 



1. Planococcus citreus (Menge) Migula 



M. agilis-citreus Menge : Centralblatt f. Bakteriologie, XII, 1893, 49. 

 PI. citreus Migula, I.e. 



Morphology. Cocci in pairs or sometimes short chains or irregular groups. 



Each coccus has a flagellum which is easily demonstrated by Loffler's 



method, and is about six times its diameter in length. Aerobic. Gelatin 



not liquefied. Form a yellow pigment. 

 Gelatin colonies. A diffuse cloudiness around the colonies, which extends 



over the plate. 

 Gelatin stab. A slight growth in depth ; on the surface, growth round, intense 



yellow. 

 Agar slant. Growth pale, thin, limited, becoming in three days yellow, more 



spreading, and viscid. - 

 Bouillon. Turbid, a yellow viscid sediment; no scum. 

 Potato. Slight growth, becoming bright yellow. 

 Milk. Not coagulated. Optimum temperature 20 . 

 Habitat. Isolated from an infusion of peas ; probably from the air. 



2. Planococcus agilis (Ali-Cohen) 



M. agilis Ali-Cohen : Centralblatt L Bakteriologie, VI, 1889, 33. 



Morphology . Cocci round slightly oval, 1 .0 /x, as diplococci. short chains, or 



in tetrads. Stain by Gram's method. Flagella demonstrated. On media 



a rose-colored pigment. 

 Gelatin stab. For some time a dry hollow funnel; liquefaction does not 



commence until after 3-4 weeks. 

 Agar slant. Growth pinkish-red. 

 Potato. As before. No growth at yj C. 

 According to Migula, I.e., this form shows in hay infusions Sarcina forms, 



and is classed by the latter as a Planosarcina. 



3. Planococcus tetragenus (Mendoza) 



Af. tetragenus-mobilis-ventriculi Mendoza : Centralblatt f. Bakteriologie, VI, 1889, 566. 

 From morphological and cultural characters indt. from M. tetragenus. 



PLANOSARCINA (Migula I.e.) 



Cocci spherical, mostly in twos and tetrads. Division in three directions of 

 space, but rarely do the cells remain united in packets, the latter usually 

 observed only in sugar-free media ; cells freely motile ; flagella long or 



