Volume 1

Some experiments on larvicides / Ronald Ross and E.S. Edie.

  • Ronald Ross
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Some experiments on larvicides / Ronald Ross and E.S. Edie. Source: Wellcome Collection.

    3/10 page 385
    [Reprinted from the ‘Annals of Tropical Medicine and Parasitology,’ Vol. V, No. 3, December, 1911} 385 SOME EXPERIMENTS ON LARVICIDES BY SiO RiWROSS)K..C:BieF- Ri S:, AND Pee Noe eC. (Receeved for publication 17 July, 1911) At present the substance in most general use as a larvicide is petroleum, which acts by forming a thin film on the surface of the water, thereby drowning the larvae when they rise to the surface to breathe. In the case of enclosed bodies of water, such as wells and tanks, this usually acts admirably at first, but in the course of a short time the film, unless very thick, gets broken. This happens much more readily in pools or stagnant places on river banks where mosquitos breed. The film of petroleum in these cases soon gets broken or blown to one side sufficiently to allow the mosquitos to lay their eggs, and the larvae to develop into mosquitos. Moreover, the presence of grass or weeds on the banks of these pools prevents the formation of an unbroken film over the whole surface, and this permits the reproductive processes to go on more or less uninterruptedly. : | | Petroleum has other disadvantages arising from its inflammability and its liquid nature, which render it less convenient for transit. An ideal larvicide would appear to be a solid substance which kills larvae even when used in the form of an extremely dilute solution. This would be convenient for use, as no great weight of material would have to be carried from place to place. The solution, when diluted to the maximum point at which it will still kill larvae in a reasonable time must also be harmless to men and domestic animals if the water is liable to be used for drinking purposes. Should there be no chance of the water being drunk, however, a stronger solution may be used, and the larvae killed more quickly. We have tried a number of solutions as larvicides, and an
    digitised image 1
    digitised image 2
    digitised image 3