CLASSIFICATION OF DAIRY BACTERIA. 171 
Gelatine colony.—Not characteristic. A slow liquefier, forming a pit which is 
at first clear and then cloudy. No acid is produced upon litmus gelatine. 
Gelatine stab.—Begins to liquefy on the first day, infundibuliform. In ten 
days the gelatine is about 3 liquefied. 
Agar streak.—Spreading, thin, smooth, opaque, white, moist, and later 
wrinkled. Quite luxuriant. 
Fermentation tubes.—There is a very slight acidity in all three sugars. No 
gas and no closed arm growth. 
Bouillon.—After three days there is a sediment, a turbidity, and a membra- 
nous pellicle. 
Milk.—Is rendered alkaline, curdled, and subsequently digested both at 20° 
and at 37° 
Potato,—Spreading, flat, irregular surface or wrinkled, and becoming blue- 
black. F 
Grows better at 37°, very little at 20° Aerobic. 
B. lactis arborescens If, An arborescent spore-producing bacillus. ‘This 
organism was found originally in 1899 and a second culture was isolated from 
dust in 1904. The original culture was kept in the laboratory for four years” 
and then tested again. It was found to agree with the original description ex- 
cept that it no longer produced the arborescent growth in gelatine. 
Morphology.—Size, 1.54-4ux .84. No chains nor capsules; spores, sometimes 
in the ends of the rods and sometimes in the center; Gram stain positive. 
Gelatine colony.—Filamentous, I cm, in diameter, of radiating knotted fibers 
and sometimes showing secondary radiations from the knots; slowly liquefying. 
In Atmus gelatine deep dry pits with radiating filaments. 
Gelatine stab.—A dry pit, which later liquefies. Needle growth arborescent. 
Agar streak.—Very thin, scarcely visible, covering the whole surface, white. 
Fermentation tubes.—No acidity, gas, or closed arm growth in any sugar 
bouillon. ; 
Bouillon.—A flocculent sediment, a slight turbidity and a tough scum. 
Milk.—No action. 
Potato.—Thin, not luxuriant, diffuse gray or brown. 
.Grows at 20° and 37°. Aerobic. 
B. lactis rhizoides n. s. A rhizoid, non-arborescent bacillus. 
Morphology.—Size, 34x .84. No chains, no spores, no capsules, Gram stain 
negative. 
Gelatine colony.—A myceloid colony, siowly liquefying. On “tmus gelatine 
the colony is proteus like. 
Gelatine stab.—A needle growth and a saccate liquefaction, beginning in three 
or four days. 
Agar streak.—Spreading, smooth, thin, transparent, white, luxuriant, moist. 
Fermentation tubes.—No acidity, gas, nor closed arm growth in any sugar 
bouillon. 
