Report of the malaria expedition of the Liverpool School of Tropical Medicine and Medical Parasitology / by Ronald Ross, H.E. Annett, E.E. Austen ; with supplementary reports by G.M. Giles and R. Fielding-Ould.
- Ross, Ronald, Sir, 1857-1932.
- Date:
- 1900
Licence: In copyright
Credit: Report of the malaria expedition of the Liverpool School of Tropical Medicine and Medical Parasitology / by Ronald Ross, H.E. Annett, E.E. Austen ; with supplementary reports by G.M. Giles and R. Fielding-Ould. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![(7.) Embankments favour malaria.— They also favour the formation of surface puddles. (8.) Towns are Inimical to malaria.—Stagnant surface puddles are not likely to be as numerous in crowded, well-drained cities, as in rural areas. (9.) Cultivation and surface drainage tend to remove malaria.-- They also tend to remove waste water suitable for Anopheles and lying on the ground. (10.) Malaria is not particularly; connected with large bodies of water. Gnats do not often breed in such. (11.) Malaria occurs on ships.—Gnats, including Anopheles., visit ships. (12.) It is particularly dangerous to sleep in malarious places, especially at night.—Gnats easily bite sleeping persons, and usually feed at night. (13.) Ground floors are most dangerous.- Gnats seem to remain near the ground. (14.) Mosquito-nets protect from malaria.—They protect also from gnats. (15.) Warmth favours malaria.—It favours also gnats, and the Haemamoebidas within them. In the remarkable work [i] which seems to be the first published exposition of the gnat- theory of malaria. King suggested many of these striking analogies—and indeed based his theory on them. Laveran, Manson, Bignami, and others have also independently entertained the same ideas—which may well occur to anyone who considers the subject at all. But it is now necessary to make an important correction in these views. King—and indeed other observers -seems to have thought that all gnats rise from swamps. A close student of the bionomics of gnats, however, might have almost shattered the whole argument at the outset by remarking that many of the commonest gnats do not rise from swamps at all, but from tubs, pots, etc., in the vicinity of houses ; and are indeed most prevalent in the heart of large cities and in other places where there is little or no malaria. It is clear, then, that King's arguments can apply only to certain species of Culicidre, namely, those which breed only in pools on the ground. King also employs other analogies which seem to be less sound. Accepting the popular views, he considers that both malaria and gnats can be blown long distances, as to the summits of hills. It is probable that in many such cases the gnats really breed close at hand ; though the observer, under the influence of the popular superstition, prefers to think that his malaria comes from the nearest marsh, although that marsh mav be miles distant. King also suggests that white men are more susceptible than black men, because gnats can see the former more easily. As a matter of fact, it is always observed that gnats prefer to settle on dark surfaces ; while the susceptibility of white men is more probably due to comparative absence of immunity than to more frequent infection. 22. Are other Insects besides Anopheles hospitable to the Human Haema- mcebidae?—Returning to the subject just touched upon, it will be readily perceived that out of the fifteen analogies given in the last paragraph, no less than nine (the first nine) can apply only to insects which breed in pools of water on the ground. For instance, they will not apply to species of gnats which usually breed in vessels of water. Such gnats cannot be said to have a localized distribution, because they are to be found in the neighbourhood of almost every dwelling](https://iiif.wellcomecollection.org/image/b21458674_0045.jp2/full/800%2C/0/default.jpg)
