Licence: In copyright
Credit: The prevention of malaria. Source: Wellcome Collection.
Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.
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![reproduce by simultaneous sporulation ; that the febrile paroxysm in the patient commences at the moment when these spores are liberated (just as Rasori had divined); and that the parasites of quartan and mild tertian fever are morphologically different [1886]. A little later, Canalis, and Marchiafava and Celli dis- covered similar facts regarding the malignant parasites, and showed that they differ from the quartan and mild tertian parasites ; and Marchiafava and Bignami suggested that they are of two varieties, the malignant tertian and the quotidian. In 1885 Danilewsky discovered similar parasites in birds and several other animals; and subsequently Marchiafava, Celli, Bignami, Mannaberg and others, made many careful studies of the parasites, and of their effects in human beings ; Romanowsky found the proper way to stain them; and many observers verified these researches in various parts of the world—the literature amounting to some hundreds of publications. 4. Speculations regarding the Mode of Infection.—But the question now arose—an all-important question in connection with the prevention of the disease—How do these parasites manage to effect an entry into the blood of men and animals ? Most observers, remembering that the disease often abounds in the neighbourhood of marshes, assumed at once that Laveran's parasites must be capable of living in a changed form in stagnant water; and some actually sought them there. Thus Grassi and Calandruccio suggested that a free living amoeba is really the external stage of the organism. On the other hand, experiments to infect healthy persons by water from marshes, made by Marchiafava and Celli [1885], Marino [1890], and especially Agenore Zeri [1890] failed entirely. Zeri gave marsh water to nine persons to drink in doses from 1*5 to 3 litres a day for a number of days. To another five persons he gave the water by clyster ; and to sixteen by spray inhalation—yet no paludism followed. Like all negative results, his are not absolutely con- clusive—since the failure may have been due to some unforeseen](https://iiif.wellcomecollection.org/image/b21351600_0034.jp2/full/800%2C/0/default.jpg)
