37 



Removing rank vegetation round the house, cutting 

 down trees close to the windows, and taking away flower- 

 pots from the verandahs, seem often to assist towards the 

 same result I prefer houses to be situated in an open, 

 well-kept " compound," with trees at a distance ; and I 

 always dislike (in the tropics) houses surrounded by fertile 

 gardens full of cisterns, irrigation pools, and the like. 

 Towns in the tropics should contain as little bush, rank 

 vegetation, and long grass as possible. On the other hand, 

 I do not think that there is much objection to a moderate 

 number of large trees ; and experience shows that, if 

 breed ing- waters are carefully excluded, mosquitoes may 

 not exist even in proximity to much vegetation. 



In dealing with mosquitoes then, the first thing to be 

 done is to remove the breeding-grounds. Attempts to kill 

 the adults will not, as a rule, be profitable, because the 

 time taken in making such attempts will generally be 

 better spent in attacking the larvae. 



In some cases, however, notably in houses infected with 

 yellow fever or malaria, it becomes necessary to destroy 

 adult mosquitoes, because it may be safely assumed that 

 many of the insects contain the germs of these diseases. 

 The insects can be easily killed by hand as they sit on the 

 walls ; or can be caught in butterfly nets, or by placing 

 bottles over them when they are seated. But the method 

 most frequently adopted is that of closing the doors and 

 windows and burning some insecticide substance in the 

 house. 



Numerous patent insecticides are in common use for 

 the destruction of green-fly and other pests by fumigation 

 in conservatories, and can usually be obtained from 

 gardeners and chemists. When these are not locally pro- 



