190 NON-BACTERIAL DISEASES 



lesions." A third monkey (C) received " 5 c.c. of filtrate representing the viscera of 

 9 flies which had had an opportunity to feed on infected cord for 18 hours. They 

 were then removed to a clean receptacle for 6 hours, when they were etherized, and 

 their legs, wings and heads removed. The viscera were then taken out with sterile 

 instruments, ground and filtered as usual and injected as above." The animal died 

 with marked symptoms on the 14th day and " at autopsy the gross lesions of the cord 

 were characteristic and the microscopic sections were also typical." 



The writers conclude that " the domestic fly (J/, domestica) 

 can carry the virus of poliomyeHtis in an active state for several 

 days upon the surface of the body, and for several hours within 

 the gastro-intestinal tract." 



Flexner (191 2) who has very closely studied the subject 

 writes as follows : " The preponderance of cases in the late 

 summer and autumn months early suggested an insect carrier 

 of the infection. House-flies can act as passive contaminators, 

 since virus survives on the body and within the gullet of these 

 insects." 



The observers quoted have undoubtedly proved that under 

 experimental conditions non-biting flies can convey the virus, 

 but up to the present we have little knowledge of what part they 

 play in the dissemination of the disease. Biting flies, such as 

 Stomoxys calcitrans, may also play a part. 



Small-pox or variola. 



The only published account of the possible relation of flies to 

 small-pox is that of Hervieux (1904). He states that Laforque 

 at Tamorna-Djedida, in the Province of Constantine, observed 

 that during an epidemic of small-pox the children who were 

 attacked lived in the south-west of the village, the northern part 

 of the village remaining free from the disease. He thought that 

 this was due to the distribution of flies and mosquitoes by the 

 prevailing wind. Laforque himself believed that flies played an 

 important part in the spread of the virus of small-pox. 



Tropical sore. 



Hirsch (1886, p. 681) states that Seviziat (1875) believed 

 that this disease might be spread by ivi/iged insixts. Laveran 

 (1880) considered that flies might carry the disease. No recent 

 observations on the subject have been published. 



