558 



DESCRIPTION OF SPECIES. 



Micrococcus rosettaceus (Zim- 

 mermann). Cocci '7 to 1 p in diam., 

 singly, and in masses. 



Colonies circular, whitish, or 

 greyish-yellow. 



Inoculated in the depth of gela- 

 tine the growth is very scanty in 

 the track of the needle, but 

 spreads over the surface as a grey 

 rosette. 



On agar a smooth layer with den- 

 tated margin is formed. 



On potato the growth is faintly 

 yellowish. 



They occur in water. 



Micrococcus roseus (Eisen- 

 berg). Cocci forming pink colonies, 

 and a rose-coloured growth on the 

 surface of nutrient agar-agar. 



They were found in sputum in a 

 case of influenza. 



Micrococcus salivarius septi- 

 CUS (Biondi). Oval cocci, diplo- 

 cocci, in chains and small masses ; 

 capsulated. 



They grow best on acid gelatine, 

 or in an atmosphere of carbonic 

 acid. 



Colonies are small and circular, 

 with an opalescent centre and a 

 transparent margin, with sharply 

 defined outline. In the interior of 

 the colonies there is an appearance 

 of a network. 



Inoculated in the depth of gela- 

 tine the cocci form a delicate fila- 

 ment and white dots on the free 

 surface. 



On agar the cultures should be 

 made direct from the blood. The 

 growth appears on the surface and 

 resembles dewdrops. 



Broth cultures remain clear. 



They are fatal to mice in twenty- 

 four to seventy-two hours, and to 

 rabbits in fifteen to thirty days, 

 producing septicaemia. Attenuated 

 cultures are said to give immunity. 



They were found in the saliva of 

 healthy and diseased persons. 



Micrococcus stellatus (Mas- 

 chek). Cocci singly. 



Colonies stellate. 



Inoculated in the depth of gela- 

 tine a branching growth appears in 

 the track of the needle. The jelly 

 becomes brownish. 



On potato the growth is brownish- 

 yellow and shining. 



They occur in water. 



Micrococcus tetragenus 

 (Gaffkey). Cocci about 1 //, in 

 diam., in tetrads, and surrounded 

 by a hyaline capsule. 



Colonies form in twenty-four to 

 forty-eight hours as small white 

 dots, which are finely granular, and 

 have a vitreous lustre ; when they 

 reach the surface they form thick 

 raised masses. 



Inoculated in the depth of gela- 

 tine, the cocci form an irregular 

 white growth, especially in the 

 upper part of the track of the 

 needle. 



On agar the colonies occur along 

 the needle track, and are white, 

 round and circumscribed. 



On potato they form a thick, 

 slimy, viscous layer. 



White mice inoculated with a 

 minute quantity of a pure-cultiva- 

 tion die in from two to ten days, 

 and the groups of the characteristic 

 tetrads may be found in the capil- 

 laries throughout the body, especi- 

 ally in the spleen, lung and kidney. 



Double infection can be produced 

 by inoculating a mouse with a 

 pure cultivation of Bacillus an- 

 thracis two or three days after 

 inoculation with Micrococcus tetra- 

 genus. On examination after 

 death, the capillaries of the lungs, 

 liver and kidney are filled with 

 both anthrax bacilli and masses of 

 tetrads (Plate V., Fig. 3). 



Micrococcus tetragenus 

 mobilis ventriculi (Mendoza). 

 Cocci in tetrads ; capsulated ; 

 motile. 



Colonies circular, whitish and 

 granular. 



Inoculated in the depth of gela- 

 tine they grow on the free surface 

 only, and give off a peculiar odour. 



They were isolated from the 

 stomach. 



Micrococcus tetragenus sub- 

 flavus (Von Besser). Cocci singly, 

 and in tetrads. 



They do not grow on gelatine. 



Colonies on agar are brown and 

 irregular in contour. 



