The Campaign in Havana 235 



ing them to the bites of infected Aedes calopus, in 

 the hope of producing mild attacks of yellow fever, 

 and thus conferring immunity. It was soon found, 

 however, that the severity of the attack could not 

 be controlled, and this work was abandoned. 



The board of army surgeons who verified Dr. 

 Carlos Finlay's theory of the transmission of yellow 

 fever by the mosquito, and made use of Dr. H. R. 

 Carter's observations on time of incubation, had no 

 opportunity to study the natural life history or the 

 possibilities of controlling the Aedes calopus; it 

 was therefore natural that they did not suggest 

 the methods of procedure needful for yellow 

 fever control. 



Cplonel Gorgas decided to ascertain at once 

 the possibility of Aedes calopus destruction on a 

 large scale throughout the city, to determine what 

 could be accomplished along this line. Work 

 of this nature had not been attempted before, and 

 all facts of importance relating to Aedes calopus 

 destruction were collected as the work progressed. 

 He believed that the propagation of this mosquito 

 cotdd be controlled, but few other people at that 

 time believed as he did. It was the general 

 opinion, with few exceptions, that an impossible 

 task had been undertaken. 



The possibilities of the use of oil for purposes 



