228 SPECIAL BACTERIOLOGY 



BACILLUS MEGATERIUM. 

 (De Barry.) 



Found in the earth, air, and on the leaves of cooked cabbages. 



Microscopical Appearances. Very long (sometimes 10 p and 

 2*5 /x thick), slightly bent bacilli with round ends. Involution forms 

 often present. 



Motility. Slightly motile ; flagella four to eight, arranged on the 

 sides (peritricha). 



Spore Formation. Endogenous, with spores nearly as long as the 

 cells. (For Photomicrograph of rods and spores, see Fig. 83.) 



Biological Characters. Strongly aerobic ; optimum temperature, 

 20 C. 



On Gelatine Plates, kidney or sickle-shaped granular colonies, that 

 liquefy the medium slowly. 



On Agar, a whitish coating. 



On Potatoes, a thick greyish-yellow coating. 



On all the media it forms a slimy mass ; and according to Giinther, 

 should be classified with the capsule bacteria. 



BACTERIUM ZOPFII. 



Found by Kurth in the intestinal contents of a chicken in 1883. 

 It has also been found in water and faeces. Gunther found it in 

 sausages in 1897. 



Microscopical Appearances. Short, plump bacilli, 2 to 5 //. long 

 and 0*75 to 1 ft broad, forming long, short-jointed chains. 



Motility. Motile. 



Staining Reactions. By the ordinary methods and also by the 

 Gram method. 



Biological Characters. Aerobic ; at 37 C. the growth is not so 

 luxuriant as at lower temperatures. 



On Gelatine Plates. Examined with a low power the colonies consist 

 of long threads coiled up like tangled balls. 



In Gelatine Stab Cultures, the growth, which takes place only on the 

 surface, consists of a coating of finely-arranged radiating threads. Old 

 stab cultures are inodorous. 



On A gar, at 37 C., a thin greyish coating develops. 



In Bouillon, at 37 C., the growth is hardly visible. 



Milk is not altered. 



