Lectures on the malarial fevers / by William Sydney Thayer.

Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on the malarial fevers / by William Sydney Thayer. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    are rarely seen excepting in the blood of internal organs, the spleen, liver, hone marrow, brain. Both these observers noted, in this type of fever, the presence of the crescentic and ovoid bodies originally described by Laveran, and recognized the fact that they develop from the small hyaline forms, both asserting that they do not appear until the clinical symptoms have lasted for some days or weeks. The interpretation of the significance of these bodies offered by Canalis and Marchiafava and Celli differs considerably. Thus Canalis distinguishes two distinct cycles in the life history of the parasite : (1) A more rapid cycle similar to that above described, and lasting, he believes, not less than two days on the average, though it may be as short as twenty-four hours. (2) A slower cycle associated with the development of crescentic bodies, in which he believes he has made out seg- menting forms; an observation which, however, few succeed- ing students have been able to confirm. This cycle lasts a much longer time, varying, he believes, in different cases. The period elapsing from the beginning of the amoeboid stage to the appearance of the crescents is not less than three or four days. Marchiafava and Celli, on the other hand, considered that the cycle of existence of the parasite from the youngest forms to the segmenting bodies lasted a varying length of time be- tween twenty-four and thirty-six hours. In some instances, with very rapid development, the parasite undergoes early segmentation before the accumulation of any pigment. They have never observed evidences of segmentation in the cres- centic bodies. A large number of confirmatory observations have been