274 THE DISSEMINATION OF OTHER DISEASES BY FLIES 



externally and then dissected out the alimentary canal, with which 

 he made cultures. In the case of flies which had lived for forty- 

 eight hours after feeding, the second and third cultures represented 

 pure cultures of the cholera spirillum. 



Simmonds (1892) in Hamburg placed flies on a fresh cholera 

 intestine, and afterwards confined them from five to forty-five 

 minutes in a vessel in which they could fly about. Roll cultures 

 were then made and colonies of the cholera spirillum were obtained 

 after forty-eight hours. Colonies were also obtained from a fly one 

 and a half hours after having access to a cholera intestine, and also 

 fi-om flies caught in a cholera post-mortem room. Uffelmann 

 (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 proboscis and feed upon a juicy piece of meat 

 that was subsequently 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 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. 



Tsuzuki (I.e.) caught flies in a cholera house in Tientsin and 

 isolated the cholera vibrios fi'om them by incubating the flies in 

 bouillon and making plate cultures fi^om the bouillon. Flies con- 

 fined in a cage were also shown to transfer the cholera vibrios from 

 a cholera culture to a culture plate of sterile agar. 



Chantemesse (1905) isolated cholera vibrios fi-om the feet of 



