The Campaign in Havana 241 



ings. The floors of all rooms were swept after 

 each fumigation, and definite evidence obtained 

 of the decrease in the number of Aedes calopus. 

 Having definitely established the possibility of 

 greatly reducing the number of these mosquitoes 

 in Havana, it was easy to foresee that by con- 

 tinued reduction very few of them need exist in 

 the city; and that it was within the bounds of 

 possibility to eradicate them. 



It was found that the tenement house districts, 

 locally called Casas de vicino, were the most 

 difficult to control. In these houses several fami- 

 lies used in common a yard, or patio, in which 

 their water-holding containers were placed. It 

 frequently happened that the owner of a container 

 holding mosquito larvae preferred not to claim 

 ownership through fear of arrest, and at times it 

 was very difficult to prove who was the real owner. 



At one time many tenants hid the red earthen- 

 ware jars {tinajas) containing their day's water 

 supply. The coming of the inspector was signalled 

 along the street and the water containers disap- 

 peared as though by magic. It even became neces- 

 sary to use a list of all water containers in some 

 districts to avoid missing any having larvae, and 

 to save time during inspection. 



The experimental work on the prophylactic 

 16 



