156 STORRS AGRICULTURAL EXPERIMENT STATION. 
Gelatine colony.—A slow liquefying pit, or sometimes a dry pit without lique- . 
faction, but with a dense colony at the bottom. 
Gelatine stab.—No true liquefaction, but a deep, dry pit is formed. | 
Agar streak.—A luxuriant growth, filiform, raised, smooth, Opaque, white, 
moist. 
fermentation tubes.—No acidity, gas, nor closed arm growth in sugar 
bouillon. 
Bourllon.—A granular sediment and decided turbidity, with a membranous 
pellicle. 
Milk.—No change except a slight alkalinity. 
Potato.—A nodose, convex, contoured growth, gray in color, moist, and not 
luxuriant. The potato is discolored. 
Grows better at 20° than at 37°. Aerobic. 
Ps. lactis Robertii n. s. A white, non-acid, liquefying monotrich. This 
organism was found in Middletown and New York city milk. A second 
variety, found at Storrs, differed in points shown in brackets. 
Morphology.—Size, 2u x .74-.9" [Im x 3H]. Large rods with square ends. 
No chains. Gram stain positive. No capsules and no spores. 
Gelatine colony.—A rapidly liquefying colony, with a greenish-orange pig- 
ment. [Brownish. ] 
Gelatine stab.—A rapid liquefier, stratiform, with a clear yellow liquid. [Slow 
liquefier. | 
Agar streak.—Luxuriant, raised, smooth, moist, white. [Dry and wrinkled. | 
Fermentation tubes.—No acidity or gas in any bouillon, but growth occurs in 
closed arm in all cases. 
Bouillon.—A sediment, decided turbidity, and membranous pellicle. 
Milk.—Rendered alkaline, curdled and digested. It has an odor and a green- 
ish color. [Greenish color and developed. | 
Potato.—Moderately luxuriant, filiform, flat, smooth, brown. [Spreading 
flesh color. ] | 
Grows at both 20° and 37°. Facultative anaerobic. 
The Storrs type should, perhaps, be called variety A. The culture from New 
York did not produce greenish milk, 
Ps. lactis aurean.s\ A yellow, liquefying monotrich. Found only once, in 
New York city milk. 
Morphology.—Size, 1.44 x Iu. No spores, no capsules, no chains. Gram 
stain positive. . 
Gelatine colony.—A slow liquefier, with a dark-ringed colony; round. On 
litmus gelatine it is lobed at the edge and not acid. 
Gelatine stab.—A filiform needle growth, with a flat surface. Liquefaction 
begins in one day; stratiform. 
Agar streak.—Luxuriant, filiform, raised, papillate, of a lemon-yellow color. 
w."* 

