296 The Control of Mosquitoes 



containers within the garbage cans. Where the 

 houses were close together it was difficult for the 

 inspectors to find the guilty individual. Appar- 

 ently it was not easy for the people to change their 

 habits. It was found necessary to keep the grass 

 short near houses, so that water containers could 

 be easily found. 



The interiors of all houses were inspected for 

 water containers, which disappeared as the inspec- 

 tor approached. Usually the tenants emptied 

 water vessels at the back door, while the inspec- 

 tor was entering at the front. 



In 1904 houses in the Canal Zone were not 

 screened. Each American employee was furnished 

 with a mosquito bar, but they were not used in a 

 way to make biting impossible. Even bars 

 that were intact, when improperly tucked in 

 around the mattresses, proved ineffective. Many 

 people roll in bed, and thus come in contact with 

 the mosquito bar while asleep; and mosquitoes 

 bite through the bar and the sleeper may be un- 

 aware of it. It was also found that bars were 

 easily torn, and seldom promptly repaired. In 

 order to make the bars effective, the sanitary 

 department undertook to keep those of canal 

 employees in repair, free of charge. 



After the houses were screened, and the number 



