120 THE HOUSE FLY— DISEASE CARRIER 



the flies were a perfect pest ; they were everywhere, and 

 in and on every article of food. It is impossible not to 

 regard them as important factors in the dissemination 

 of enteric fever. Our opinion is further strengthened 

 by the fact that enteric fever in South Africa practi- 

 cally ceases every year with the cold weather, and this 

 was the case at Bloemfontein. For though the days 

 after lo a.m. were as an English summer day, and the 

 temperature in our tents was rarely below 70° and 

 often about 80° F., the nights were very cold, and 

 often frosty, and with the cold nights the flies disap- 

 peared. It seemed to us that the cold weather reduced 

 the number of enteric cases by killing these pests.' 



*'Smith (1903), also writing of South Africa, states 

 that a neglected trench 'becomes an open privy with an 

 infected surface soil around it; the flies browse in it 

 in the daytime and occupy the men's tents at night. 

 On visiting a deserted camp during the recent campaign 

 it was common to find half a dozen or so open latrines 

 containing a fetid mass of excreta and maggots; this 

 because the responsible persons so often failed to com- 

 ply with the regulations for encampments by filling in 

 latrines on the departure of the troops.' 



"Austen (1904, p. 656) vividly recalls 'a latrine in 

 a certain standing camp in South Africa during the 

 late war, in which the conditions as regards flies were 

 precisely as described by Major Smith. It is only fair 

 to say that the ground was extremely hard and stony, 

 so that very little soil was available for covering up 

 the contents of the trench. On visiting the latrine 



