418 PATHOGENIC MICROCOCCI 
nute, spherical, semi-transparent colonies are developed among the impfstrich ; 
these have a bluish tint by reflected light; they may become confluent, form- 
ing a thin layer with well-defined margins. Upon gelatin plates, at 16° to 
18° C., colonies are first visible at the end of two or three days; they are 
spherical and slightly granular, at first transparent and later of a pale-yellow 
color by transmitted light, which gradually becomes brown. At the end of 
five or six weeks the colonies are still quite small, well defined, and opaque. 
Pathogenesis.—Pure cultures injected into the mammary gland of cows 
and goats gave rise to a mastitis resembling in its development that from 
which the streptococcus was obtained in the first instance. Injections into 
the cavity of the abdomen or into a vein, of one cubic centimetre of a pure 
culture, gave a negative result in dogs, cats, rabbits, and guinea-pigs. 
DIPLOCOCCUS OF PNEUMONIA IN HORSES. 
Obtained by Schiitz (1887) from the lungs of horses affected with pneu- 
monia. 
Morphology.—Oval cocci, usually in pairs. surrounded by a homogene- 
ous, transparent capsule. * 
Does not stain by Gram’s method. 
Biological Characters.—An aérobic, non-liquefying micrococcus. Grows 
at the room temperature. Upon gelatin plates forms small, spherical, white 
colonies. 
In gelatin stick cultures grows along the line of puncture 4s small, white, 
separate colonies, which grow larger without becoming confluent. Upon 
the surface of agar small transparent drops are developed along the impf- 
strich. 
~ Pathogenesis.—The injection of a pure culture into the lung of a horse 
produces pneumonia and causes its death in eight or nine days. Pathogenic 
for rabbits, guinea-pigs, and mice. 
STREPTOCOCCUS CORYZH CONTAGIOSZ EQUORUM. 
Obtained by Schiitz (1888) from pus from the lymphatic glands involved 
in horses sutfering from the disease known in Germany as Druse des 
Pferdes. 
Morphology.—Oval cocci, in pairs, in chains containing three or four 
elements, or in long chaplets. d 
Stains with the usual aniline colors—very intensely with Weigert’s or 
Ehbrlich’s solution. 
Biological Characters.—An aérobic and facultative anaérobic micrococ- 
cus. Grows slowly at the room temperature, more rapidly at 37° C. Upon 
gelatin plates at the end of three to five days minute colonies become visible; 
these never exceed the size of a pin’s head. In gelatin stab cultures growth 
upon the surface is scanty or absent; along the line of puncture minute 
colonies are developed in rows. Upon agar plates, at 37° C., at the end of 
twenty-four hours lentil-shaped colonies are developed the size of a pin’s 
head; under a low power the superficial colonies are seen to have a well-de- 
fined, opaque nucleus surrounded by a grayish, transparent marginal zone, 
which represents a half-fluid, slimy growth which does not extend after the 
third day and later disappears entirely; the deep colonies are at first well- 
defined, and later surrounded by wing-like outgrowths. Upon blood serum, 
at 37° C., pees transparent drops are first developed; these become con- 
fluent and form a viscid and tolerably thick layer; this later becomes dry 
and iridescent. 
Pathogenesis.--Pathogenic for horses and for mice, producing in these 
animals an abscess at the point of inoculation, and metastatic abscesses in 
the neighboring lymphatic glands, Not pathogenic for rabbits, guinea-pigs, 
or pigeons. 
