Tropical diseases : a manual of the diseases of warm climates / by Sir Patrick Manson.
- Patrick Manson
- Date:
- 1907 (repr. 1912)
Licence: In copyright
Credit: Tropical diseases : a manual of the diseases of warm climates / by Sir Patrick Manson. 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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![centre of the parasite, though sometimes nearer one end ; and a bow-like and exceedingly delicate line that, springing from a point somewhat inside the rounded-oflF tips of the horns of the crescent, bridges Its concavity. Manifestly this bow represents the outline of the remains of the blood corpuscle in which the joarasite had developed. In many in- stances, especially in stained specimens, the con- tinuation of the red blood corpuscle can be dis- tinctly traced around the convexity of the crescent. This circumstance, together with the fact that the materia] included by the bow and also occasionally seen as a delicate, sometimes slightly jagged fringe around the convexity of the crescent, gives the staining reactions of hsemo- globin, proves that this form of the malaria parasite, like the ordinary amoeboid bodies already described, is also in- tracorpuscular. Slight differ- ences, particularly as regards the sharpness or obtuseness of the horns, occur; but, on jf\„ R u< ^ ■ ■> whole, the crescents are iig. 6.—Malaria parasite: -j: ■ twill crescents. Very uniiorm m appearance. Very rarely twin or double crescents—that is, two crescents in one corpuscle are encountered (Fig. 6). Crescents differ in appearance accordingtotheirage; in some the hsemozoin granules are scattered through- out the parasite, in others they are concentrated, and in a third class the protoplasm shows vacuolation and other signs of degeneration. The first, it is believed, are young and immature, the second mature, and the third effete parasites. In the first, the h^mozoin rods sometimes exhibit slight translation as well as vibra- tory movements; in the two latter the ha-mozoin is quiescent. The first, or younger, type of crescent stains uniformly ; but in the second type the staining, in many instances, is markedly bipolar, a clear, unstained area occupying the middle of each horn, whilst a zone of stained protoplasm forms the](https://iiif.wellcomecollection.org/image/b21360352_0038.jp2/full/800%2C/0/default.jpg)
