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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    iB HISTORY [Sect. Also about the same time, during his famous studies on cholera in India, R. Koch had the same notion ; but he mentioned it only in his lectures to students [Nuttall, 1899, p. 77, and Ross 1905, p. 73]. Ten years later, and some years after I had commenced my studies of the subject, P. Manson supported the mosquito hypothesis in a rather short paper [1894]. But he added a new and a stronger argument to those already given. In the blood of man the parasites of malaria consist chiefly of forms which reproduce themselves indefinitely by spore formation ; but in addition to these there are other forms which appear to possess no function in the human body, but which, shortly after the blood containing them is drawn from the patient’s finger, often emit long and actively motile filaments which may break away from the parent cell, and wriggle about rapidly in the fluid under the microscope. For a long time these bodies had been the subjects of discussion. Some observers, chiefly of the Italian school, held that they represent only the dying struggles of the parasite; others, including Laveran and Danilewsky, thought that they are really living bodies; and Mannaberg even suggested that they may be connected with the life-history of the parasites outside the human body—though he did not explain how this could be. Manson now offered an explanation. He thought that when a mosquito sucks the blood, these parasites enter its stomach with the blood, and there, in a few minutes, emit their motile filaments just as they do under the microscope. The motile filaments, he thought, were flagellated spores, which next pass through the walls of the mosquito’s stomach and take up their abode in its tissues, where they must develop further. Two years later he repeated this hypothesis [1896] with the assistance of my preliminary researches, but added some conjectures as to the future fate of the “flagellated spores.” He still thought that mosquitos die on the surface of water a few days after laying their eggs in it. The malaria germs
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