(158) 



STRUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. 399 



numbers in the intestines of flies from a hospital ward, and 

 also in the dejections which occurred on the windows and 

 walls of the ward. Hoffmann (1886) also found tubercle 

 bacilli in the excreta of flies in the room where a patient had 

 died of tuberculosis, and he also found the bacilli in the 

 intestinal contents. One out -of three guinea-pigs which were 

 inoculated with the intestines died ; two inoculations with the 

 excreta had no effect, which led him to believe that the bacilli 

 became less virulent in passing through the alimentary tract. 

 But Celli (1. c.) records experiments in which two rabbits 

 inoculated with the excreta of flies fed with tubercular sputum 

 developed the disease. Hay ward (1904) obtained tubercle 

 bacilli in ten out of sixteen cultures made from flies which 

 had been caught feeding on bottles containing tuberculous 

 sputum. Tubercle bacilli were also recovered from cultures 

 made from the fasces of flies which had fed in the same 

 manner, which apparently caused a kind of diarrhoea in the 

 flies, and they died from two to three days afterwards. 

 Fasces of flies fed on tubercular sputum were rubbed up in 

 sterile water and injected into the peritoneal cavity ot'guiuea- 

 pigs, which developed tuberculosis. Buchanan (I.e.) allowed 

 flies to walk over a film of tubercular sputum and then over 

 agar ; a guinea-pig died of tuberculosis in thirty-six days by 

 inoculating it with the resulting culture. 



5. Ophthalmia. 



Flies have been suggested as playing an important part in 

 the spread of conjunctivitis, especially Egyptian ophthalmia, 

 and although, so far as I have been able to discover, we have 

 no bacteriological evidence in favour of the belief, the circum- 

 stantial evidence is sufficiently strong to warrant it. 



In speaking of its occurrence at Biskra, Laveran (1880) 

 says that in the hot season the eyelids of the indigenous 

 children are covered with flies, to the attentions of which 

 they submit; in this way the infectious discharge is carried 

 on the legs and probosces of flies to the healthy children. 



