THE MOSQUITO THEORY OF MALARIA. 45 



the habits of the various species of mosquito and as regards the 

 capacity of each for carrying malaria, is not complete. All I can 

 now say is that if my anticipations be realized — if it be found that 

 the malaria-beariug species of mosquito multiply only in small 

 isolated collections of water which can easily be dissipated — we 

 shall possess a simple mode of eliminating malaria from certain 

 localities. 



I limit this statement to certain localities only, because it is 

 obvious that where the breeding pools are very numerous, as in 

 water-logged country, or where the inhabitants are not sufficiently 

 advanced to take the necessary precautions, we can scarcely expect 

 the recent observations to be of much use — at least for some years 

 to come. And this limitation must, I fear, exclude most of the rural 

 areas in India. 



Where, however, the breeding pools are not very numerous, 

 and where there is anything approaching a competent sanitary es- 

 tablishment, we may, I think, hope to reap the benefit of these 

 discoveries. And this should apply to the most crowded areas, such 

 as those of cities, towns and cantonments, and also to tea, coffee, 

 and indigo estates, and perhaps to military camps. 



For instance, malaria causes an enormous amount of sickness 

 among the poor in most Indian cities. Here the common species 

 of mosquitoes breed in the precincts of almost all the houses, and 

 can therefore scarcely be exterminated; but pools suitable for the 

 spotted-winged varieties are comparatively scarce, being found only 

 on vacant areas, ill-kept gardens, or beside roads in very excep- 

 tional positions where they can neither dry up quickly nor contain 

 fish. Thus a single small puddle may supply the dangerous mos- 

 quitoes to several square miles containing a crowded population: 

 if this be detected and drained off — which will generally cost only 

 a very few rupees — we may expect malaria to vanish from that 

 particular area. 



The same considerations will apply to military cantonments 

 and estates under cultivation. In many such malaria causes the 

 bulk of the sickness, and may often, I think, originate from two 

 or three small puddles of a few square yards in size. Thus in a 

 malarious part of the cantonment of Secunderabad I found the 

 larvae of spotted-winged mosquitoes only after a long search in a 

 single little pool which could be filled up with a few cart-loads of 

 town rubbish. 



In making these suggestions I do not wish to excite hopes which 

 may ultimately prove to have been unfounded. We do not yet 

 know all the dangerous species- of mosquito, nor do we even pos- 

 sess an exhaustive knowledge of the haunts and habits of any one 



