FLIES AND EPIDEMICS 13 



excretions of one to the food of another. Thus the 

 fly is more subtle in its methods, but the way is surer, 

 for helpless children are infected at a tender age ; and 

 the fly runs less risk to her own life than does the 

 mosquito, because as the former does not bite we have 

 less desire to kill her in moments of rage. 



The discovery of the mode of transmission of 

 malaria was published at the end of the last century, 

 and that of yellow fever during the first years of the 

 present century. Then the fly question began to be 

 taken up seriously, and the Spanish-American and 

 Boer Wars brought in their train a mass of evidence 

 inculpating this insect in the spread of typhoid. 

 According to Dr. Graham Smith, in his Report to 

 the Local Government Board 1909, it is stated that 

 during the typhoid epidemic in the Southern camps 

 in Florida while the former campaign was in pro- 

 gress there were countless flies ; these were breeding 

 in the sewage pits usually placed near the kitchen 

 tents. The largest number of cases of typhoid occurred 

 among the cavalrymen the way in which horses attract 

 flies is well known ; it was noted at the time how the 

 flies went from the sewage pits to the kitchens. The 

 Report quotes : " 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." The 

 American Army Medical Department issued a circular 

 to the effect that flies are probably carriers of typhoid. 

 " 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 con- 

 tained in their excreta to the food which is exposed." 

 Walter Reed, who was a member of the American 

 Commission which discovered the part played by 

 2* 



