CLASSIFICATION OF DAIRY BACTERIA. 155 
Potato.—Luxuriant, spreading, convex, smooth, grayish-brown. Potato 
chocolate-colored. 
Grows well at 20° and 37°. Aerobic. 
Ps. lactis contorta n. >. A polypiform, spore-bearing, monotrich, This 
organism has been found only once, in milk from New York. 
Morphology.—Size, 1-54 x .84. It apparently produces spores and has a 
single flagellum, although it was lost before the study was completed. 
Gelatine colony.—A slow, liquefying pit, at frst umbonate. On dtmus gela- 
tine it is highly lobed and contorted, and does not liquefy in four days. 
Gelatine stab—A filiform needle growth, with a flat surface growth, which 
later becomes a dry pit. True liquefaction does not appear. 
Agar streak,—A moderate growth, filiform, convex, smooth, opaque, of a 
cream-white color. 
Fermentation tubes.—No acidity nor gas in any sugar bouillon, but growth 
in closed arm. 
Bouillon.—A sediment, slight turbidity, and a granular pellicle. 
7 Milk.—Rendered alkaline, but not curdled. At 20° there is a slight diges- 
tion and the milk is slightly slimy. 
Potato.—Luxuriant growth, filiform, convex, smooth, opaque, of a gray color. 
Grows better at 20° than at 37° Facultative anaerobic. 
Ps. lactis minuta n. >. A very small spore-bearing monotrich. This 
organism has been found only once, in milk directly from the udder. 
Morphology.—Size, .6u-.8u x .3#. A very short rod, not forming chains. 
No spores, no capsules. Gram stain positive. 
Gelatine colony.—Round, raised, smooth, entire colonies, of a brownish- 
yellow color, which, later, liquefy. 
Gelatine stab.—A slow liquefaction, crateriform. 
Agar streak.—Luxuriant, filiform, raised, translucent, porcelain-white, moist. 
Fermentation tubes.—No acidity, gas, nor closed arm growth in any sugar 
bouillon. 
Bouillon,—A flocculent sediment and a slight turbidity, but no pellicle. 
Milk.—Rendered acid, is not curdled or digested, and no other change is 
noticeable. 
Potato.—No visible growth. 
Grows at both 20° and 37° = Aerobic. 
‘ 
Ps. lactis mina n. ». A Gram-staining, spore-bearing, monotrich, This 
organism has been found only once, in New York city milk. It is somewhat 
similar to the last, but differs in some important points. 
Morphology.—Size, 1.4u-1.84 x .6u. A slenderrod. No spores, no capsules. 
Cram stain negative. 
