Medical report / Federated Malay States.

  • Federated Malay States. Medical Department.
Date:
[1914]
Catalogue details

Licence: Public Domain Mark

Credit: Medical report / Federated Malay States. Source: Wellcome Collection.

    34/34 (page 30)
    Is VTURALIZATION. To keep such creatures as millions alive by nursing them is one thing, to get them to breed while under protection is another (and in both of these we can congratulate ourselves on our success) but to get them to naturalize themselves, to look after themselves, and survive the competition of the natural world is quite another matter. Each creature, it may be trite to remark, is so finely adapted to his environment—in fact is the complement of his environment—That the chances are that he will not survive if taken out of the environment to which he is complementary. However, we must remember that notable instances of the chances of survival of a creature being enhanced have occurred after importation into a fresh environment. The rabbit was an importation into Australia, and the lady-bird insect into California. Each has flourished exceedingly, and I may mention here that although there were local species of lady-bird in California, which were ineffective in stopping the scale disease of plants yet the imported lady-bird not only flourished exceedingly, but was effective in eradicating the scale disease. The first stage of our experiment with the millions, therefore, was to nurse them and to get them to breed, and the next stage has been to try to colonize them in the “ natural waters ” of the country. In this stage up to date we have, I think, had a notable success in the culture on Midlands Estate. Here the fish are not fed or protected in any way from natural enemies, in fact “ big fish ” are constantly being caught in the reservoir yet they have increased from 80 to many thousands. This place is just such a one in which “ millions ” will be placed for anti-malarial work in the future and the outlook is therefore very cheerful. Moreover, if the “millions ” have reappeared in the Seremban swamp a great success will have been achieved, for there are hundreds of thousands of acres of similar swamp in this country in which the fish could be placed. We have chosen a very good place at Ayer Angat for an experimental culture in a swamp, and when the situation has been prepared for the fish we will be enabled to proceed a stage still further in our courses. The swamp at Puchong would, I think, offer a further suitable breeding place for the fish. Altogether the chances seem to me to be very rosy that this little fish will, with care, become one of the indigenous creatures of Malaya. Whether it will be as successful as was the lady-bird in .California when it comes to eradication of disease remains to be seen. Millions as Larva Destroyers. When I came back from Morib on 2nd September I found two of the aquarium tanks (four feet square) swarming with mosquito larvae. I then put five “ millions ” in each of the tanks, and by 10th September I could not find a single larva remaining. Each fish must have eaten countless numbers. Therefore, it is certain that if we can colonize these fish, that they must do some good, even if they only eat one larva each during their lifetime. And when, as Sir Eonald Eoss, has shown mathematically, it is not necessary to do more than destroy a certain proportion of larvae in order to completely eradicate malaria, I think the chances that they will prove efficient malaria-preventers are decidedly hopeful where they can be used for that purpose. \\ To summarize, we have very good evidence that we will be able to naturalize this fish, and ipso facto they will be efficient anti-malarial agents. C. STEICKLAND, Travelling Medical Entomologist, F.M.S.