NON- PATHOGENIC BACTERIA IOI 



Indian bacillus in that it grows at a temperature of 5 C., and 

 does not develop upon potatoes or blood-serum. 



Bacillus Phosphorescens Gelidus (Forster). Origin. 

 Surfaces of salt-water fish. 



Form. Short, thick rods, looking oval sometimes; zooglea 

 are often formed. 



Properties. Motile; does not liquefy gelatin; a beautiful 

 phosphorescence from the surface of fish; it can be photographed 

 by its own light. 



Colonies. Grows best between 10 and 20 C.; grows slowly, 

 and mostly on the surface. The material must contain salt. 

 A bouillon made with sea-water or 3 to 4 per cent, common 

 salt will suffice. The colonies appear as those of the Phospho- 

 rescens Indicus. 



Fresh herring laid between two plates will often show phos- 

 phorescence in twenty-four hours. 



Three varieties require glucose in the culture before they give 

 out any glow. They are Bacterium Pflugeri, Bacterium Fischeri, 

 and Bacterium Balticum. They do not dissolve gelatin. 



Several very indistinct species, found in waters from factories 

 and in some of the mineral waters, deserve yet to be men- 

 tioned. They have been given various names by observers; 

 and a new classification created. Such are the crenothrix, 

 cladothrix,a,nd'beggiatoa,)which belong to the "higher bacteria." 



Crenothrix KUhniana (Rabenhorst) . Long filaments 

 joined at one end; little rod-like bodies form in the filaments, 

 and these break up into spores. 



Zooglea are also formed by means of spores, and these can 

 become so thick as to plug up pipes and carriers of water. 

 They are not injurious to health. 



Cladothrix Dichotoma (Cohn). Very common in dirty 

 waters. The filaments branch out at acute angles, otherwise 

 resembling the crenothrix; accumulations of ocher-colored 

 slime, consisting of filaments of this organism, are found in 

 springs and streams. (See Fig. 128.) 



Leptothrix Buccalis. In the mouth, long filaments or 

 threads resembling bacteria are commonly found. At one end 



