INSECTS AND HUMAN DISEASE 121 



decaying matter ovei which they have walked and 

 dropping it as they go. The deplorable number of deaths 

 from typhoid that took place in the Spanish- American and 

 Boer wars focussed the attention of entomologists on the 

 house fly. A Government report concerning the conditions 

 of the former war states that : " It was impossible to keep 

 the flies from the already cooked food, even if a man kept 

 one hand over his plate and ate with the other " ; whilst 

 the American Army Medical Department, in a circular 

 showing that flies were probably carriers of typhoid, 

 states that : " They swarm about faecal matter and filth of 

 all kinds deposited on the ground or in shallow pits, and 

 directly convey infectious material attached to their feet, 

 or contained in their excreta, to the food which is exposed." 

 During the war an Army Typhoid Commission was 

 instituted, and its findings made it more and more clear 

 that house flies were responsible for the spread of typhoid. 

 Dr Vaughan, who drew up a report for the Commission, 

 laid especial stress on three points : that flies pass direct 

 from faecal matter to food, as was plainly shown, when 

 lime had been recently sprinkled over the contents of the 

 pits, by the fact that insects whitened with lime were seen 

 on the food ; that the officers suffered less in proportion 

 than the men their mess tents were effectually screened ; 

 that with the approach of the cold weather and the con- 

 sequent reduction in numbers of the flies, typhoid gradually 

 decreased. The report continues : " It is possible for the 

 fly to carry the typhoid bacillus in two ways. In the first 

 place, faecal matter containing the typhoid germ may 

 adhere to the fly and be mechanically transported. In 

 the second place, it is possible that the typhoid bacillus 

 may be carried in the digestive organs of the fly and be 

 deposited with the excrement." 



During the Boer war matters were no better. Tooth and 

 & 



Calverley, writing of typhoid during the war, state that 

 " in a tent full of men, all apparently ill, one may almost 



