NON-PATHOGENIC BACTERIA. 83 



Stab Cultures. Looks like a very delicate thread along the 

 needle thrust. 



Spirillum. Spirillum Rubrum. (Esmarch.) 



Origin. Body of a mouse dead with septicaemia. 



.Form. Spirals of variable length, long joints, tlagella on each 

 end , no spores. 



Properties. Does not liquefy gelatine ; very motile ; produces 

 a wine-red pigment, which develops only by absence of oxygen. 



Growth. Can grow with oxygen, but is then colorless ; grows 

 very slowly ; ten to twelve days before any sign ; grows best at 

 37 C. 



Gelatine Roll Cultures. Small, round; first gray, then wine- 

 red colonies. 



Stab Cultures. A red-colored growth along the whole line ; it 

 is deepest below, getting paler as it approaches the surface. 



Spirillum Concentricum. (Kitasato.) 



Origin. Decomposed blood. 



Form. Short spirals, two to three turns, with pointed ends ; 

 it has flagella on the ends. 



Properties. Very motile ; does not liquefy gelatine. 



Growth. Very slow ; mostly on the surface ; best at ordinary 

 temperatures. 



Plates. A growth of rings concentrically arranged, every 

 alternate one being transparent ; the furthest one from the 

 centre possessing small projections. 



Stab Cultures. Growth mostly on the surface. 



Sarcina. Cocci in cubes or packets of colonies. A great 

 number have been isolated ; many producing very beautiful 

 pigments. The majority of them found in the air. 



Sarcina Lutea. (Schroter.) 



Origin. Air. 



Form. Very large cocci in pairs ; tetrads and groups of 

 tetrads. 



Properties. Liquefies gelatine slowly ; produces sulphur-yel- 

 low pigment. 



Growth. Slowly ; at various temperatures ; strongly aerobic. 



Plates. Small, round, yellow colonies. 



Stab Cultures. Grows more rapidly, the growth being nearly 



