DISSEMINATION OF CHOLERA BY FLIES 273 



may infect fuud during cholera times and that they must play an 

 important part in the dissemination of the disease when they are 

 numerous. He also draws attention to the fact that the W(jrst 

 cholera months are those in which insects abound. 



Buchanan (1897), in a description of a gaol epidemic of 

 cholera which occurred at Burdvvan in Juno, 1896, states that 

 swarms of flies occurred about the prison, outside which there 

 were a number of huts containing cholera cases. Numbers of 

 flies were blown from the sides where the huts lay into the prison 

 enclosure, where they settled on the food of prisoners. Only 

 those prisoners which were fed in the gaol enclosure nearest the 

 huts acquired cholera, the others remaining healthy. 



Tsuzuki (1904), reporting upon the cholera outbreak in 

 Northern China in 1902, states that " flies in China are a terrible 

 infliction to the stranger," and remarks that if they are capable of 

 carrying about the cholera germ they must play an important part 

 in the spread of the disease. His experiments, mentioned later, 

 demonstrated that flies are able under natural conditions to carry 

 the cholera spirillum. 



Bacteriological evidence. 



Maddox (1885) appears to have been the first to conduct 

 experiments with a view to demonstrating the ability of the flies 

 to carry cholera spirillum, or as it was then called, the " comma 

 bacillus." He fed the flies Calliphora vomitoria and Eristalis 

 tenOyX (the "drone-fly") on pure and impure cultures of the 

 spirillum, and appears to have found the motile spirillum in the 

 faeces of the flies. He concludes that these insects may .act as 

 disseminators of cholera. During a cholera epidemic Tizzoni and 

 Cattani (1886), working in Bologna, showed experimentally that 

 flies were able to carry the " comma bacillus" on their feet. They 

 also obtained, in tw^o of these experiments, the spirillum ft-om 

 cultures made with flies from one of the cholera wards. Sawt- 

 chenko (1892) made a number of careful experiments. Flies were 

 fed on bouillon culture of the cholera spirillum, and to be certain 

 that the subsequent results should not be vitiated by the presence 

 of the spii'illum on the exterior of the flies, he di&infected them 



H, H.-F. 18 



