662 NON-PATHOGENIC BACILLI. 



Morphology. Straight or slightly curved bacilli with round ends; about 

 two /* long and one-third as broad; grow out into filaments of various 

 lengths. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile bacillus. Spore formation not observed. Cultures give off a 

 silvery phosphorescence, which is less intense than with the previously de- 

 scribed species. Grows at the room temperature in the usual culture media 

 best at 25 C. ; does not grow in the incubating oven at 34 C. Upon 

 gelatin plates, at the end of twenty-four hours at the room temperature, 

 small, hyaline discs are developed, which under the microscope are seen to 

 be finely granular and light-brown in color; they are irregularly circular in 

 outline and about 0.7 millimetre in diameter; the deep colonies are con- 

 siderably smaller, mulberry-like in structure, and straw-yellow in color. 

 At the end of forty-eight hours shallow liquefaction has occurred beneath 

 the superficial colonies, in watch-glass form, and about two millimetres in 

 diameter ; under the microscope a central mass of a straw- yellow color is seen, 

 around this a narrow, light-brown zone with granular contents, and outside 

 of this a broader peripheral zone, from which fine, radiating outgrowths are 

 given off into the non-liquefied gelatin. At the same time (forty-eight hours) 

 the deep colonies have a diameter of 0.3 to 0.45 millimetre and a more or less 

 polygonal contour; they are straw-yellow in color and consist of a finely 

 granular central mass, surrounded by a slender, marginal zone which is 

 marked by radial striations. After complete liquefaction of the gelatin the 

 colonies, which remain attached to the glass plate, have a lemon-yellow color. 

 In gelatin stick cultures (six per cent) liquefaction occurs beneath the super- 

 ficial layer which is developed, in form of a shallow watch glass, and 

 gradually extends in diameter and depth; growth also occurs along the line 

 of puncture, and the cultures resemble those of Bacillus cyaneo-phosphores- 

 cens, but with less rapid development and liquefaction of the gelatin ; also 

 without the formation of hair-like outgrowths into the non-liquefied 

 gelatin. The addition of 2.7 per cent of sodium chloride is favorable for the 

 development of this as for the previously described species of phosphorescent 

 bacilli; on the other hand, the addition of two per cent of glucose exercises 

 a restraining influence upon the growth of all the species studied by Katz. 

 In bouillon a diffuse cloudiness is produced by the growth of this bacillus, 

 and a mycoderma is formed upon the surface. No growth occurs in simple 

 meat infusion, but an abundant development when 2.5 per cent of sodium 

 chloride is added to this. Upon sterilized fish a shining, sticky, yellowish- 

 gray layer is developed. No growth upon potato. 



343. BACILLUS PHOSPHORESCENS INDICUS (Fischer). 



Found in sea water from the Gulf of Mexico. 



Morphology. Bacilli with rounded and pointed ends, from two to three 

 times as long as broad; length from one-sixth to one-quarter the diameter 

 of a red blood corpuscle ; solitary or in pairs ; also in short filaments. 



Stains readily with the aniline colors, but unstained places are often seen 

 in the interior of the rods. 



Biological Characters. An aerobic, liquefying, motile bacillus. Spore 

 formation not observed. Cultures, especially upon animal substances and 

 in presence of certain soda salts, exhibit a decided phosphorescence in the 

 dark ; this depends upon free access of air, and is most marked at a tem- 

 perature of 25 to 30 C. It is no longer manifested at a temperature of 

 C., and is neutralized by putrefaction. Grows in the usual culture media 

 at the room temperature not so well in the incubating oven. Upon gelatin 

 plates, at the end of thirty-six hours, small, round, grayish- white, punctiform 

 colonies are developed ; under a low power these are seen to be spherical, 

 with well-defined outlines, and have a sea-green color with a pink shimmer; 

 later they become granular, have a wavy outline and a dirty-yellow color. 

 In gelatin stick cultures, at the end of four days, a grayish-white line of 



