398 
C. GORDON HEWITT. 
access to a cholera intestine, and also from flies caught in a 
cholera post-mortem room. Uffelraann (1892) fed two flies on 
liquefied cultures of the cholera spirillum, and after keeping 
one of them for an hour in a glass he obtained 10,500 
colonies from it by means of a roll culture ; from the other, 
which was kept two hours under the glass, he obtained 
twenty-five colonies. In a further experiment he placed one 
of the two flies similarly infected with the spirillum in a glass 
of sterilised milk, which it was allowed to drink. The milk 
was then kept for sixteen hours at a temperature of 20-21° C., 
after which it was shaken, and cultures were made from it; 
one drop of milk yielded over one hundred colonies of the 
spirillum. The other fly was allowed to touch with its pro- 
boscis and feed upon a piece of juicy meat that was sub- 
sequently scraped. From one half of the surface twenty 
colonies, and from the other half one hundred colonies, of the 
spirillum were obtained. These experiments show the danger 
which may result if flies having access to a cholera patient, and 
bearing the spirillum, have access also to the food. Macrae 
(1894) records experiments in which boiled milk was exposed 
in different parts of the gaol at Gaya in India, where cholera 
and flies were prevalent. Not only did this milk become 
infected, but the milk placed in the cowsheds also became 
infected. The flies had access both to the cholera stools and 
to such food as rice and milk. 
These foregoing experiments prove beyond doubt the ability 
of flies to carry the cholera spirillum, both internally and 
externally, in a virulent condition, and to infect food. 
4. Tuberculosis. 
Although it may be considered to be hardly necessary to 
introduce flies as a means of disseminating the tubercle 
bacillus, it has, nevertheless, been proved experimentally 
that they ai'e able to carry the bacillus in a virulent condition. 
As early as 1887 Spillman and Haushalter carried on experi- 
ments in which they found the tubercle bacillus in large 
