NON-PATHOGENIC BACTERIA. 



Bacillus phosphorescens Indicus. Obtained from sea- 

 water; a small, thick, rod-shaped bacillus with rounded 

 ends, also forming threads; actively motile; not stained 

 by Gram's method; liquefies gelatin; aerobic. It grows 

 slowly, best between 20 and 30 C, upon the usual media; 

 except milk and potato. Its cultures, when old, especially 

 when on animal- nutrient-media and in the presence of 

 certain sodium salts, are phosphorescent in the dark. 



There are various other bacilli which produce phospho- 

 rescence, some of which do not liquefy gelatin. 



Bacillus mycoides (Bacillus ramosus, Wurzelbacillus). 

 Found in the earth and in water, very common; a large, 

 short bacillus with rounded ends, often forming chains and 

 threads ; slightly motile ; liquefies gelatin ; aerobic ; forms 

 centrally located, oval spores; gro\vs rapidly at room and 

 incubator temperatures upon the usual media. It is said 

 to rapidly decompose albumin with the formation of 

 ammonia. 



Bacillus subtilis (Hay bacillus). Found on hay, in the 

 air, water, ground and decomposing fluids; very common; 

 a large bacillus somewhat resembling the anthrax bacillus 

 in form, with rounded ends, often forming chains or long 

 filaments; motile; possessing flagella; liquefies gelatin; 

 aerobic; it is stained by Gram's method. It may have 

 large, centrally located spores, which form best on potato 

 at about 30 C. The spores are extremely resistant to heat 

 and to chemical germicides. It grows best at about 30 C. 

 upon the ordinary culture-media; milk is peptonized. 

 Bacillus subtilis may easily be isolated in pure culture by 

 adding finely-cut hay to bouillon ; place in the steam ster- 

 ilizer for five or ten minutes; then let the tubes develop in 

 the incubator. Plates made from the bouillon will probably 

 show colonies of the bacillus subtilis only, as the steam 

 may be expected to have destroyed all organisms except 



