Bacterium Phosphorescens, Fischer. 



PHOTOBACTEEIDM PHOSPHORESCENS. 



Origin. — Found in the watei* of the harbor of Kiel, also- 

 on dead sea-fish, oysters, etc. From these it may spread to- 

 meat in butcher shops. 



Form. — Short, thick bacillus, with rounded ends; some- 

 times almost a coccus. It is usually in pairs, but may form 

 threads. Involution forms soon develop. 



Motility.- — No motion. 



Sporulation. — This has not been observed. 



Anilin dyes. — Stain readily; so does Gram's method. 



Growth. — Is moderately rapid. The cultures show in 

 the dark a marked bluish-green phosphorescence (see p. 116). 



Qelatin plates. — Show small, white, glistenmsr colonies, which do- 

 not liquefy. The border is sharp, irregular, and the contents are 

 granular, and show several concentric rings. 



Stab culture. — A slight granular growth along the line of inocu- 

 lation. Most abundant on the surface, where it forms forms a thin 

 grayish white covering. Eventually, the gelatin is colored a yellow- 

 ish brown. 



Streak culture. — On aqar, potato, etc., growth is limited to the 

 line of inoculation. It grows well on fish, beef, bread, fats, etc. 



Oxygen requirements.- — It is a facultative anaerobe. 

 The production of light depends upon the presence of oxy- 

 gen, and is, therefore, most marked on the surface growths. 

 The intensity of the light may diminish, and, may become 

 lost — attenuation. It may be restored by growth on suita- 

 ble media, such as fish.' 



Temperature. — Does not grow in the incubator, but may 

 grow at 0°. 



Behavior to gelatin. — It does not liquefy gelatin, but 

 can ferment sugar. 



Pathogenesis. — No effect on animals. One phosphores- 

 cing bacillus is said to produce a disease in certain Crus- 

 tacea. 



1 A good medium for the growth of these organisms is prepared 

 in the same manner as ordinary gelatin, by adding 500 g. of chopped 

 fish to 1,000 c.c. of water. The material is digested, and strained. 

 To the filtrate 100 g. of gelatin, 40 g. of salt, 5 g. of glycerin, and 

 5 g. of asparagin are added, and. the mixture is rendered slightly 

 alkaline fp. 155). The liquid after heating is filtered, placed in tubes 

 and sterilized. 



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