392 
C. GORDON HEWITT, 
near the points fonnci to be most insanitary. He shows, as 
English investigators have also shown, how the curves of 
fatal cases correspond with the temperature curves and with 
the curves of the activity and prevalence of flies which were 
obtained by actual counts. He also adduced bacteriological 
evidence, and it is stated that one fly was found to be carrying 
over one hundi’ed thousand fecal bacteria. 
Bacteriological evidence. — In addition to the evidence 
of Jackson, to which reference has been made, further proof 
that flies are able to carry the typhoid bacillus has been 
available for some years. Celli (1888) recovered the Bacillus 
typhi abdominalis from the dejections of flies which had 
been fed on cultures of the same, and he was able to prove 
that they passed through the alimentary tract in a virulent 
state by subsequent Inoculation experiments. Bicker (1903) 
found that wlien flies were fed upon t\'phoid cultui’es they 
could contaminate objects upon which they rested. The 
typhoid bacilli were present in the head and on the wings 
and legs of the fly five days after feeding, and in the alimen- 
tary tract nine days after. Firth and Horrocks (1902), in 
their experiments, took a small dish containing a rich emul- 
sion in sugar made from a twenty-four-hour agar slope of 
Bacillus typhosus recently obtained from an enteric stool 
and rubbed up with fine soil. This was introduced with some 
infected honey into a cage of flies together with sterile litmus 
agar plates and dishes containing sterile broth, which were 
placed at a short distance from the infected soil and honey. 
Flies were seen to settle on the infected matter and on the 
agar and broth. The agar plates and broth were removed 
after a few days, and after incubation at 37° C. for twenty- 
four hours colonies of Bacillus typhosus were found on 
the agar plates and the bacillus was recovered from the 
broth. In a further experiment the infected material was 
dusted over with fine earth to represent superficially buried 
dejecta, and the bacillus was isolated from agar plates upon 
which the flies had subsequently walked, as in the former 
experiment. They also found the bacillus on the heads, wings. 
