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CLASSIFICATION OF DAIRY BACTERIA. Priel 
Gelatine colony.—Spreads slightly over the surface, white, yellowish or 
brownish, lobed or round or rather thin. The colony is not characteristic. 
Gelatine stab.—An abundant needle and a surface growth. 
Agar streak.—White to yellowish, moist, not luxuriant. 
fermentation tubes.—No acidity in any sugar bouillon; there is no gas or 
closed arm growth. f 
Boutllon.—A sediment and turbidity but no pellicle. 
Milk. — Usually no action, although a few cultures show a slight acidity. 
Potato.—Very scanty, grey-white, or sometimes no growth. 
Grows at both 20° and 37°. Aerobic. 
Variations from the above are shown in color, from a white to a yellowish; in 
the formulation of a pellicle in one culture; and in the failure to stain by the 
Gram method. 
Variety A.—We recognize as a distinct variety one form that grows luxu- 
riantly on potato and has a less tendency to form a yellowish pigment. This 
type has also a slight tendency to produce an acidity in milk, in this respect 
agreeing with M7. candius of Barthel, which is probably the same. Variety A 
is equally common with the type described. 
One culture which would naturally belong here shows relations to YW. lactis 
albus in that it digests milk, but does not liquefy gelatine. Its characters are 
as follows: 
Variety B. Digesting milk without lquefying gelatine. 
Morphology.—A micrococcus. Size, .64. The Gram stain is negative. 
Gelatine colony.—Very small, yellowish, surface colonies, smooth, convex, 
entire, moist. 
Gelatine stab.—A needle growth and a convex surface. 
Agar streak.—Filiform, raised, smooth, transparent, moist, luxuriant. In 
some cases wrinkled. 
fermentation tubes.—No acidity or gas in any bouillon. Usually no closed 
arm growth, but one culture showed growth in closed arm. 
Bouillon.—A sediment and turbidity; a pellicle sometimes forms and some- 
times not. . 
Milk.—Becomes alkaline and digests. This digestion becomes complete in 
three weeks, and is unusual since the organism does not liquefy gelatine. 
Potato.—Luxuriant, filiform, capitate, cream color. Potato not discolored. 
Grows at 20° and 37°. Aerobic. 
The description of this Coccus appeared to us to agree closely with that of 
Streptococcus pyogenes. To see how closely they agree, we obtained a culture 
of the latter from the bacteriological laboratory at Yale Medical School, and 
compared it with our cultures side by side. In all cultural characters we found 
that the two agreed so closely as to be indistinguishabie. Whether this indicates 
that they are identical we would not at present determine, but the identity in ° 
cultural characters of this common pathogenic Coccus and this most common 
dairy organism is at least suggestive. In fresh milk this type is probably the 
most common of all dairy bacteria. 
