220 GNATS UK MOSQUITOES— CHAPTEK VIII 



employment being continuously and systematically kept 

 up, and for the purposes of an initial experiment such as 

 his, or in any case where immediate results are demanded, 

 no other plan is applicable. Sanitation against malaria on 

 radical lines will everywhere require years of continuous 

 and progressive effort, and as long as it remains uncom- 

 pleted we must necessarily depend upon hand to mouth 

 expedients, such as the use of larvicides. But whatever 

 plan be adopted those who hold the purse strings must 

 reconcile themselves to the fact that the prevention of 

 malaria is impossible without considerable outlay, and they 

 must further be prepared to see a great deal of it expended, 

 though not really wasted, in futile attempts, for we shall no 

 more immediately hit upon the best method of dealing with 

 this difficulty than we have in the deodorisation of sewage 

 or any other sanitary problem. For the present, while 

 radical measures should always be kept in view and under- 

 taken as funds and opportunity permit, we must content 

 ourselves with temporary methods, and it is well to remember 

 that though we may not be able even locally to " exter- 

 minate " the carriers of disease, it is always worth while to 

 diminish their numbers. Every breeding pool filled in or 

 otherwise dealt with, means one possible focus for dissemi- 

 nation the less, and a great deal might be soon accomplished 

 by the systematic attention to the immediate neighbourhood 

 of barracks and other dwellings. 



Turning then to measures of this class, it is clear that 

 the insects might be attacked either in the aquatic or the 

 serial stage of their existence, but that they may be far more 

 easily got at in the former. Durmg their adult life, the only 

 period during which much advantage is likely to be gained 

 by attempts to destroy them is that of hybernation, and it 

 has been shown that, in uniformly warm clnnates, they 

 cannot really be said to liybernate at all. Where, however, 

 they do so, their destruction is of the first importance, and, 

 owing to the sluggish condition of the insects, not so 

 impracticable as might be imagined. The impregnated 

 hybernating females are, it must be remembered, the main 

 hope of the race for the generation of the coming year, and 



