CLASSIFICATION OF DAIRY BACTERIA. 157 
Fermentation tubes,—No acidity, gas, nor closed arm growth in any sugar 
bouillon. 
Bouillon.—A sediment, slight turbidity, and ring-formed pellicle. 
Milk.—Rendered alkaline, but no other change noticed. 
Potato.—A luxuriant growth, spreading or beaded, contoured; of a lemon- 
yellow color, moist. 
Grows better at 20° than at 37° Aerobic. 
Ps. lactis aerogenes A.u.s. A gas-producing, liquefying monotrich, This 
was found in milk which had been kept at 1° for several weeks. Possibly this 
is Ps. coadunta of Wright. y 
Morphology.—Size, 1v-1.2u x .7¥-.gu. A short rod, with no chains. No 
spores, no capsules, and Gram stain negative. 
Gelatine colony.—Round, raised or ‘flat, smooth, homogeneous, with wavy 
edge. Cream-white to brownish color. On /tmzs gelatine the colony is large, 
moist and acid, like a typical B. aerogenes. 
Gelatine stab,—A very slow liquefaction. There is a beaded needle growth, 
a moderately thick surface, rather rough, and, after a long time, a liquefaction. 
Agar streak,—Thin, whitish, extending over the whole surface of the agar; 
not characteristic. 
Fermentation tubes.—Acid, gas, and closed arm growth in all sugar bouillons. 
Bouillon,—A sediment, slight turbidity and a membranous pellicle. 
Milk,—Rendered acid and promptly curdled. A very slight digestion, with 
a strong odor. ‘The digestion not always apparent, 
Potato.—Usually scanty, thin and of a porcelain-white color. 
Grows better at 20° than at 37° Facultative anaerobic. 
Ps. fluorescens Gorini, A fluorescent monotrich. This organism, received 
from Gorini, had the following characters when studied by us. A similar 
organism from Colchester milk differed in points shown in brackets. 
Morphology.—Size, 1.2u-1.84x .74%. No chains, no spores, no capsules. 
Gram stain negative. 
Gelatine colony.—A moderately transparent, liquefying colony, granular and 
cloudy. It liquefies the whole plate in time. Litmus gelatine not acid. 
Gelatine stab.—It begins to liquefy in one day, infundibuliform, with a 
tenacious scum. ([Stratiform.] 
Agar streak,—Luxuriant spreading, raised, smooth, opaque, gray. [Thin and 
flat.] The agar shows a green fluorescence. 
Fermentation tubes.—Dextrose bouillon is acid, but the others are not. No 
gas in closed arm growth in any case. 
Bouillon.—A sediment and a decided turbidity, but no pellicle. [Pellicle is 
formed. ] 
Milk.—Becomes alkaline at 20°, is curdled and completely digested, but not 
at 37° Shows a green color and strong odor. [Curdles and digests at 37°, 
without the green color.] 
