REMEDIES AGAINST MOSQUITOES 187 



sene after from fifteen to twenty days, in order to render 

 it impossible tliat any adult mosquito can be developed. 

 This period is too short, rather than too long, but it is ab- 

 solutely safe, and in any given locality observations will 

 indicate to what extent it may safely be lengthened. I 

 am quite inclined to believe that, even in tropical regions, 

 seventeen-day intervals will be perfectly safe, if the fuel 

 oil referred to above is used. My own experiments were 

 carried on with illuminating oil, and the fuel oil is more 

 jDersistent. 



The first army orders issued in Cuba (Circular No. 8, 

 Headquarters Department of Western Cuba, October 15, 

 1900) required the treatment of breeding-pools once a 

 month. The second order (General Orders No. 6, Head- 

 quarters DeiDartment of Cuba, December 21, 1900) re- 

 quired the application of kerosene twice a month. The 

 Winchester ordinance, it will be remembered, designates 

 as the times of a^Dplication once ever\^ three weeks, but 

 the mayor suggests that the first and fifteenth days of 

 each month be " oil days." 



As interesting records, the army circular and order are 

 given : 



[^Circular No. S.^ 



Headquarters Department of Western Cuba, 

 QuEMADOS, October 15, 1900. 



The following communication from tlie Chief Surgeon is \n\h- 

 lished for the information and guidance of couuiiandiug officers 

 in this department. The necessary action will be taken as tliere- 

 in recommended. 



