A research into the production, life and death of crescents in malignant tertian malaria, in treated and untreated cases, by an enumerative method ; The leucocytes in malarial fever : a method of diagnosing malaria long after it is apparently cured / by David Thomson.
- Thomson, D. (David)
- Date:
- 1911
Licence: Public Domain Mark
Credit: A research into the production, life and death of crescents in malignant tertian malaria, in treated and untreated cases, by an enumerative method ; The leucocytes in malarial fever : a method of diagnosing malaria long after it is apparently cured / by David Thomson. Source: Wellcome Collection.
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![It is, however, the second stage (sexual stage) of the parasite that I wish to consider. Less is known concerning it than of the first and second periods. No one can demonstrate how the sexual forms are produced, nor how long they live; and no effective method of killing them has been found. Research regarding this obscure stage is therefore necessary, and of great importance. When we know how to destroy the sexual malarial parasites, or how to prevent their production, we will have another powerful weapon whereby we can exterminate the disease. In this article I shall call the sexual parasites ‘crescents,’ as I have dealt only with cases of P. falciparum. The accompanying table has been compiled from the cases studied by the enumerative method used in this research. Some of the results have already been mentioned in the previous paper referred to above. THE PRODUCTION OF CRESCENTS From the figures given regarding the forty-two cases of P. falctparum studied, it is clearly noticeable that the production of crescents is extremely irregular. Certain paroxysms of fever result in a numerous brood of crescents even up to 7,000 per c.mm. of the patient’s blood. Other paroxysms produce very few or none at all. Thirty-one, or 74 per cent. of the cases, showed crescents at some time during the period of examination. Eleven, or 26 per cent., showed no crescents at any time while under observation. A. HOW ARE CRESCENTS PRODUCED AND WHERE ARE THEY DEVELOPED? All malarial experts seem agreed that the crescents are developed from the ordinary asexual spores or merozoits of the parasite. Mannaberg [1894] stated his belief that they were produced from the conjugation of two asexual parasites within a’ red corpuscle. If this is so, then the more numerous these asexual forms are, the greater is the likelihood of two or more finding their way into a red cell, that is according to the theory of probability. In Case 13 where there were 300,000 asexual parasites per c.mm. of blood, many of the red cells contained more than one parasite. In Case 18 asexual parasites were few and difficult to find (1,860 per c.mm.), and no doubly infected corpuscles could be detected; yet](https://iiif.wellcomecollection.org/image/b33445059_0004.jp2/full/800%2C/0/default.jpg)
