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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    on patients with the gametids (crescents) in their blood, and showed that the motile filaments were, as usual, extruded in the insects’ stomachs. But I speedily found that, owing to their minute and delicate structure, it was impossible to follow them further, as Manson had suggested should be done. I was therefore obliged to adopt a new procedure of my own. The insects were kept alive after being fed for several days, and were then exhaustively searched for any parasites they might contain. If such parasites were found it was possible that they might be the developed motile filaments ; and the point could be cleared up by subsequent experiments. This method was extremely laborious, but was the only one possible. For more than two years the results were completely negative. Meantime, following the later conjectures of Manson, I tried to infect healthy persons by giving them to drink water in which fed mosquitos had died. By some accident the first case appeared successful; but twenty-one succeeding experi¬ ments practically failed [1896]. For this and other reasons I abandoned this part of Manson’s hypothesis, and began to think that the insects probably carry the parasites from man to man, either depositing them by defaecation on the skin of healthy persons, or inoculating them under the skin after puncture. In August 1896, Mr Appia, Assistant Surgeon of the Civil Hospital at Bangalore, kindly submitted to the suggested experiments. Many Stegomyia and Culex, previously fed on patients, were fed on him a few days later. There was no result—the mosquitos being of the wrong species, and the period between the feedings being too short [1896]. Bignami now criticised Manson’s hypothesis [1896]; but I made a number of experiments in support of it, and showed that the extrusion of the motile filaments is really a living process and not a “death agony” as many had thought [1897]. My repeated failures, however, now persuaded me that I had probably been working with the wrong kinds of mosquitos —
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