852 
VERANUS A. MOORE. 
cate in their morphology and equally as sensitive to the influ¬ 
ence of environment as those isolated from diseased animal 
tissues. In view of this wide distribution, the presence of a 
streptococcus in any of the abnormal conditions heretofore 
mentioned cannot be considered necessarily a specific infection 
from a previous case of the same kind. In many affections 
where the specific organism has been demonstrated, such for ex¬ 
ample as diphtheria, tuberculosis, and hog cholera, strepto¬ 
cocci frequently appear in the lesions. In these cases they are 
considered as accidental or secondary invaders, although in 
some of these maladies, such as tuberculosis, they are believed 
to be of more or less secondary importance. When, however, 
the specific cause of the disease is not positively known, and 
streptococci which possess certain pathogenic powers for ex¬ 
perimental animals are constantly present and seem to stand in 
a causal relation to the disease, the pathologist is confronted 
with a puzzling problem in trying to determine the source and 
the etiologic importance of the organism in hand. In cases of 
infection leading at once to septicaemia, peritonitis or suppura¬ 
tion the explanation is more simple than in the epizootic dis¬ 
eases such as Brustseuche in horses or distemper in dogs where 
the constant presence of streptococci in the lesions can be quite 
as easily explained on the ground of their normal presence in 
the parts affected as on the hypothesis of a specific infection. 
It is in these cases that we are seeking for the crucial test. 
We have found in a few test experiments that when certain 
of the delicate streptococci which exist (are found) in external 
nature (soil or water) are introduced within the tissues of cer¬ 
tain animals they become, by reason of their activities, a source 
of irritation which causes local tissue disturbances. In a few 
instances they have produced septicaemia with fatal results. 
In cases of infection resulting in septicaemia, or in those 
where the disease is more localized as in strangles or mastitis, 
and possibly in others where the affection spreads more or less 
rapidly, we can not well escape from the feeling that the strep¬ 
tococci present in such large numbers, must either stand in a 
