DISSEMINATION OF INFECTIOUS DISEASES BY INSERTS. 
271 
guinea-pig, with the result that it died within 18 hours of a typ¬ 
ical attack of symptomatic anthrax. I was also able to secure 
the bacillus from the local lesion and liver of the dead guinea- 
pig. Control experiments were not considered necessary, as in 
the event of other flies not infected with symptomatic anthrax 
proving pathogenic, we should still prove that flies carry patho¬ 
genic organisms. 
. That they do ordinarily carry pathogenic organisms was 
proven by another experiment in which a fly that had been in 
contact with the affected organs of a tuberculous guinea-pig was 
placed under the skin of a healthy guinea-pig. The pig died 
on the second day of malignant oedema, showing that the 
bacilli of malignant oedema, or their spores, were adherent to 
or in the fly’s body coincidently with its infection with the 
tubercle bacillus. Further, a fly was allowed' to partake of a 
liquid culture of the bacterium of swine plague. This bacterium 
is uniformly fatal to rabbits. The infected fly was placed under 
the skin of a rabbit, with the result that it died within 24 hours, 
and I was able to demonstrate the presence of the bacterium o^ 
swine plague in the liver and blood of the dead animal. 
In another experiment made to decide the question of flies 
being able to convey tuberculosis by means of their excrement 
when fed on material containing the tubercle bacillus, I cap¬ 
tured a vigorous fly, placed it under a bell-glass along with a 
cover-glass on which was spread some of the tubercle film from 
a glycerine-agar culture of the bacillus. In about one hour, the 
infected cover-glass was removed and fresh clean ones were slid 
in under the bell-jar. The next day several of them were 
“specked.” A microscopic examination of one of the “specks” 
showed that the bacillus had passed through the alimentary 
canal of the fly and had been deposited on the cover-glass with 
the excrement. In order to determine if the bacilli were alive 
and virulent, one of the “ specked ” cover-glasses was placed in 
a y 2 cc. of glycerine-bouillon and shaken in order to wash off the 
excrement. A healthy guinea-pig was inoculated intra-abdomi- 
nally with this suspension, with the result that when two 
