Two monographs on malaria and the parasites of malarial fevers : I. Marchiafava and Bignami. II. Mannaberg.

Date:
1894
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Licence: Public Domain Mark

Credit: Two monographs on malaria and the parasites of malarial fevers : I. Marchiafava and Bignami. II. Mannaberg. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    bodies or in crescents ; tbe bodies in tbis case only remained alive for a short time, but did not increase in number. After all these unsuccessful attempts, it appears to be more and more probable that the malarial parasites do not exist in the external world as saprophytes, hut must live as parasites either in animal or vegetable organisms. Laveran’s supposition that possibly the gnats are the hosts of the parasites is disproved by Grassi and Calandruccio [ioo] on account of the negative experiments in feeding which were made by Calandruccio. These investigators have occupied themselves with a thorough investigation of the question as to the existence of the malarial parasite in the external world, and they believe that they are justified in drawing the conclusion from their investigations that certain species of amoebae—especially the Amoeba guttula (or gracilis)—may be regarded as their extra - parasitic form. Grassi and Calandruccio start with the assumption that the malarial parasites are to be sought amongst those Rhizopoda which are found in all malarial districts. Therefore they investigated marsh water, moist soil, rice fields, macerated hemp and linen, in a word all possible malarial seats, for Rhizopoda, and found in all of them species of the genus Amoeba and of those genera nearly related to them—the Hyalodiscus (Bactylosphserium)—present in great numbers. They imagined that the infection of men and animals occurred by the encysted amoebae being inhaled in consequence of their imponderability and presence in the air currents. They were also able, although very rarely, to prove the presence of amoeboid cysts in dew ; further they discovered them in the nasal secretion of pigeons which they had exposed for several nights to the evaporation from marshes or from malarial earth. They explain the impossibility of cultivating the parasites taken from the blood of men or animals back to the amoebas of the external world by stating that the parasites of the animal organism have been, so to say, “ spoilt,” so that they lose their capacity to again return to an independent mode of life. The most weighty objection which can be raised against Grassi and Calandruccio-’s hypothesis is this, that the amoebae mentioned by them are more widely distributed in the world than malaria itself. The weight of this objection is recognised by both authors themselves, and they reply to it that it is the greater number of the amoebae which causes the malarious regions to be such plague spots.
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