NON-PATHOGENIC BACILLI. 659 



chloride is added to this it constitutes a favorable medium. Upon the sur- 

 face of sterilized milk a tolerably abundant, sticky, glistening- layer of a 

 cream-white color is developed. Upon cooked egg a thin, grayish-white, 

 phosphorescent layer is formed. No growth on potato which has an acid 

 reaction, but when the acidity is neutralized with a solution of sodium phos- 

 phate a thin, brownish-yellow layer is developed. Small quantities of a 

 pure culture added to sea water cause it to exhibit a very decided phospho- 

 rescence, and the addition of sodium chloride to culture media favors the 

 growth of the bacillus and its phosphorescent power. Free access of oxygen 

 is essential for the growth and phosphorescence of this species. The color 

 of the light given off by fresh cultures is emerald-green ; it is less intense in 

 ao-ar cultures than in cultures in nutrient gelatin, bouillon, or upon cooked 

 fish. 



338. BACILLUS ARGENTEO-PHOSPHORESCENS NO. I. (Katz). 



Obtained from sea water at Elisabeth Bay, Sydney, New South Wales. 



Morphology. Slender, slightly curved bacilli with pointed ends, about 

 2.5 jit long and one-third as thick as they are long; solitary or in pairs; oc- 

 casionally in long, wavy filaments. 



Biological CJiaracters. An aerobic, non-liquefying, motile bacillus. 

 Spore formation not observed. Grows in the usual culture media at the 

 room temperature not in the incubator at 35 C. Upon gelatin plates 

 (six-per-ceiit gelatin), at the end of twenty hours, the superficial colonies ap- 

 pear as flat, shining, transparent drops from 0.4 to 0.6 millimetre in dia- 

 meter; under the microscope they are seen to be homogeneous and usually 

 circular in outline, with a dentate margin. The deep colonies are spherical 

 or short oval; they have a smooth, well-defined contour and pale-yellow 

 color. At the end of forty- eight hours the superficial colonies are granular, 

 pale-yellow, with an undulating contour, and about 1.25 millimetres in dia- 

 meter; at the same time the deep colonies are pea-yellow and uniformly 

 granular ; later the deep colonies present three well-defined zones ; the super- 

 ficial colonies also, at the end of twenty days, present two or three distinct 

 zones; they attain a diameter of about three millimetres. In eight-percent 

 gelatin the deep colonies, at the end of two days, are oval, and under the 

 microscope show three well-defined zones; the superficial colonies present 

 the same appearance in from four to seven days, at which time they have a 

 diameter of three millimetres later as much as seven millimetres. In gela- 

 tin stick cultures (six per cent) development occurs upon the surface as a 

 flat, shining, usually circular layer, about one cubic centimetre in diameter, 

 and of a greenish-yellow or wax-like color. No growth occurs in acid gela- 

 tin. In old gelatin cultures containing 2.7 per cent of sodium chloride 

 liquefaction sometimes occurs at a temperature approaching that at which 

 the gelatin would become liquid. In bouillon a diffuse cloudiness is pro- 

 duced and a film is formed upon the surface ; no growth occurs in flesh in- 

 fusion without the addition of peptone and salt, but the addition of 2.5 per 

 cent of sodium chloride to neutral flesh infusion makes it a favorable me- 

 dium. Upon the surface of sterilized fish a pale-yellow, glistening, sticky 

 layer is developed. Upon cooked egg a thin, grayish- white layer. No growth 

 on potato. Phosphorescence depends upon the presence of certain salts 

 especially sodium chloride in the culture medium, and upon the free access 

 of oxygen. In bouillon cultures, when a mycoderma has formed upon the 

 surface this shows phosphorescence, while the liquid below does not. The 

 light given off is of a silver-white color, and a recent culture upon the sur- 

 face of gelatin gives sufficient light to enable one to determine the time from 

 a watch in a dark room. 



339. BACILLUS ARGENTEO-PHOSPHORESCENS NO. II. (Katz). 



Obtained from phosphorescent pieces of fish found in the market at Syd- 

 ney, New South Wales. 



