Preventive Measures 313 



present; to the efficiency of the measures taken 

 by quarantine for the exclusion of yellow fever; 

 and to local conditions of housing. Each locality 

 must establish its own rules in this respect. 



Discussion has arisen at intervals regarding the 

 advisability of destroying water-holding plants 

 such as banana, alocasia, etc. We are inclined 

 to believe that danger from these plants has been 

 greatly overestimated. It is possible that larvae 

 of Aedes calopus may have been found in them, but 

 careful observation in Cuba and on the Isthmus 

 has convinced us that fully developed larvae or 

 pupas of this species seldom occur in these water- 

 holding plants, and that the banana plants are 

 unimportant in producing them. The destruction 

 of ornamental and useful plants causes opposition 

 and we would urge that, before the wholesale 

 destruction of " these plants is undertaken, very' 

 careful observations be made to determine their 

 true importance in the propagation of this 

 mosquito. 



