Mosquito brigades and how to organise them / by Ronald Ross.

Date:
1902
Catalogue details

Licence: In copyright

Credit: Mosquito brigades and how to organise them / by Ronald Ross. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    I do not recommend this procedure. The fact is that the large majority of the puddles can each be obliterated, temporarily at least, by a stroke or two of the pick and shovel, and a few basket loads of gravel. It is necessary only to set the gang at work straight away, and they will probably clear out most of the stagnant water in a few months. A formal drainage scheme had better be aban- doned until simpler methods have at least been tried and have failed. But in order to obtain the best results the superin- tendent must proceed with method. He should be guided by the following important principle : Attack first those collections of water the obliteration of which will remove the largest number of mosquitoes for the least amount of money. Thus, it is quite useless to drain stagnant water simply because it is stagnant water. The superintendent should first assure himself that it does actually contain larvae, and, better, that it constantly contains them. As already mentioned, some pools are too large, others are too small, and others are subject to scouring ; and, though these conditions often change at certain seasons, when, for instance, large pools dry up, yet some pools appear to be habitually unsuited to the larvae.* It is useless to spend much money over these. Again, it is not advisable to attack without discrimination even the pools which do contain larvae. Some contain many more larvae than others do ; and, in my experience, while larvae do occur in some con- siderable bodies of water, such as marshes or ponds, they * On revisiting Freetown after two years’ absence, I was struck by finding the larvae in exactly the same pools, however small ; while other pools pre- viously negative, remained negative. The most insignificant puddles seem to be much more permanent than would be thought possible, and year after year fill up with rain and breed mosquitoes.