four days the disease becomes established. The testicles
enlarge a little; the skin over them becomes red and
shining. The testicles themselves begin to suppurate,
and often discharge through the skin. The animal dies
in about two weeks. If such an animal be killed and its
testicles examined, the tunica vaginalis testis will be
found to contain pus, and sometimes to be partially ob-
literated by inflammatory exudation. The bacilli are pres-
ent in this pus, and can be secured from it in pure cultures.
The value of Strauss's method has, however, been less-
ened by the discovery by Kutcher,1 that a new bacillus,
which he has classified among the pseudo-tubercle ba-
cilli, produces a similiar testicular swelling when injected
into the abdominal cavity.
The purulent discharges from the noses of horses
and from other lesions of large animals generally con-
tain very few bacilli, so that their detection by the
use of the guinea-pig inoculation is made much more
The bacillus is an aerobic organism, and can be grown
in bouillon, upon agar-agar, better upon glycerin agar-
agar, very well upon blood-serum, and quite character-
istically upon potato. It grows in gelatin, but this is
not an appropriate medium, because the bacillus develops
best at temperatures at which the gelatin is liquid.
Upon 4 per cent, glycerin agar-agar plates the colonies
appear upon the second day as pale-yellow or whitish,
shining round dots. Under the microscope they appear
as brownish-yellow, thick granular masses with sharp
The culture upon agar-agar and glycerin agar-agar
occurs as a moist, shining layer not possessed of distinct
peculiarities. Upon blood-serum the growth is rather
characteristic. The colonies along the line of inoculation
first develop as circumscribed, clear, transparent drops,
which later become confluent and form a transparent
layer unaccompanied by liquefaction.
1 Zeitschrift fur Hygiene, Bd. xxi., Heft i., Dec. 6, 1895.