SOME COMMON BACTERIA SLIGHTLY PATHOGENIC 103 



Properties. Decomposes urea into ammonium carbon- 

 ate; does not liquefy gelatin. 



Growth. Grows rapidly, needing oxygen; can remain sta- 

 tionary below o C., growing again when a higher temperature 

 is reached. 



Colonies on Plate. On the surface like a drop of wax. 



Stab-cultures. Looks like a very delicate thread along the 

 needle-thrust. 



Other bacteria are found in urine in various pathologic proc- 

 esses, such as tubercle bacilli, typhoid bacilli, gonococci, and 

 other pyogenic organisms. 



Spirilla. A number of non-pathogenic spirilla have been 

 described. 



Spirillum Rubrum (Esmarch). Origin. Body of a 

 mouse dead with septicemia. 



Form. Spirals of variable length, long joints, flagella on 

 each end; no spores. 



Properties. Does not liquefy gelatin; very motile; pro- 

 duces a wine-red pigment, which develops only in 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. 



Gelatin 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. 



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 gelatin slowly; produces sulphur- 

 yellow pigment. 



Growth. Slowly, at various temperatures; strongly aerobic. 



Plates. Small, round, yellow colonies. 



