Volume 1

The prevention of malaria / by Ronald Ross ; with contributions by L.O. Howard [and others].

  • Ronald Ross
Date:
1910
Catalogue details

Licence: Public Domain Mark

Credit: The prevention of malaria / by Ronald Ross ; with contributions by L.O. Howard [and others]. Source: Wellcome Collection.

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    H The matter was reported at once to Government, and the medical press [1897]. Unfortunately no more of the large dapple-winged mosquitos could be obtained, but I found the pigmented cells in a Culex which had been caught feeding on a case of tertian malaria, and also in one of a smaller kind of dapple - winged mosquito. On this I wrote to Manson telling him to expect the full solution of the problem in a few weeks. Next day, however, I was ordered to proceed to Kherwara, a place a thousand miles distant, where there was little malaria at the time. Owing to this interruption I have never been able to identify exactly the two species of dapple¬ winged mosquitos; but from their general characters, the markings on their wings and the shape of their eggs, they were obviously Anophelines. I remained at Kherwara from September 1897 to February 1898, when the Government was good enough to put me on special duty to continue my researches in Calcutta. On arrival there I found it impossible to work with human malaria, chiefly on account of the riots caused by Mr Haffkine’s anti - plague inoculation, and therefore attacked the malaria of birds. According to Manson’s hypothesis, the motile filaments were flagellated spores capable of living in mosquitos’ tissues ; but my pigmented cells contained plasmodin, which cannot exist in spores. The discrepancy was explained by a series of researches made in 1896. Metchnikoff and Simond had found similar motile filaments in Coccidium oviforme of rabbits, and suggested that they are really sperms and not spores [1897] J and a little later MacCallum and Opie in America actually observed, in the case of one of the malaria parasites of birds (Halteridium) and one of those of men, these sperms in the act of fertilising the female cell [1897]. My pigmented cells were therefore the fertilised cells, or zygotes, still carrying the plasmodin which they originally possessed. In March 1908, I found these bodies again in Culex fatigans
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