412 PATHOGENIC MICROCOCCI 
and along the line of puncture a series of round, milk-white or yel- 
lowish masses form, which usually remain distinct, but may become 
confluent. Upon the surface of agar the growth is similar to that 
upon gelatin, or in streak inoculations may consist of a series of 
spherical, white colonies. Upon cooked potato a thick, viscous layer 
is formed of milk-white color ; the growth upon blood serum is also 
abundant, especially in the incubating oven. This micrococcus is a 
facultative anaérobic. 
Pathogenesis.—Subcutaneous inoculation of a culture of this 
micrococcus in minute quantity is fatal to white mice in from two to 
six days. The animals remain apparently well for the first day or 
two, then remain quiet and somnolent until death occurs. The cocci 
are found in comparatively small numbers in the blood of the heart, 
but are more numerous in the spleen, lungs, liver, and kidneys, from 
which organs beautiful stained preparations may be made show- 
ing the tetrads surrounded by their transparent capsule. Common 
house mice and field mice are, for the most part, immune, as are the 
rabbit and the dog. Guinea-pigs sometimes die from general infec- 
tion, and sometimes a local abscess is the only result of a subcutane- 
ous inoculation. 
MICROCOCCUS BOTRYOGENUS (Rabe). 
Synonyms.—Micrococeus of ‘‘ myko-desmoids ” of the horse; Mi- 
crococcus askoformans (Johne) ; Ascococcus Johnei (Cohn), 
First described by Bollinger (1870) ; morphological characters and 
location in the diseased tissues described by Johne (1884) ; biological 
characters determined by Rabe (1886). 
Is found in certain diffused or circumscribed growths in the con- 
nective tissue of horses—‘‘ myko-desmoids.” 
Morphology.—Micrococci, having a diameter of 1 to 1.5 yu, usu- 
ally united in pairs. 
In the tissues the cocci are united in colonies of fifty to one hun- 
dred y in diameter, and these are associated in mulberry-like masses 
visible to the naked eye. The separate colonies are enclosed in a 
homogeneous, transparent envelope—as in Ascococcus Billrothii. 
This is not the case, however, in cultures in artificial media. 
Stains with the aniline colors. 
Biological Characters.—In gelatin plate cultures spherical, 
sharply defined, silver-gray colonies are developed ; later these have 
a yellowish color and a metallic lustre, and the plate presents the ap- 
pearance of being powdered with grains of pollen. It gives off a 
peculiar fruit-like odor, reminding one of the odor of strawberries. 
In gelatin stab cultures growth occurs along the line of puncture as 
a pale grayish-white line, which later becomes milk-white; an air 
