corpuscular parasites prior to the formation of spores, may sometimes be seen to slip out from their enclosing corpuscles (Fig. 9, b, e). If these free parasites are watched, in some instances the hæmozoin they contain is seen to indulge in violent dancing movements, the body of the parasite being at the same time agitated and jerked about. Finally, "flagella" (microgametes) may be suddenly projected from the periphery (Fig. 9, c, f), very much in the same way as they are projected from the periphery of the crescent-derived sphere. Manifestly, these large
Fig.—9. a, b, c, Evolution of the flagellated body in tertian fever; d, e, f, evolution of the flagellated body in quartan fever
spherical parasites and the flagellated bodies arising from some of them correspond to the crescent-derived sphere and crescent-derived flagellated body.
Conditions favouring and retarding eruption of microgametes.—Ross has shown that, provided the blood containing the crescent body be prevented from coming in contact with the air, as can be secured by pricking the finger through vaseline, evolution does not proceed. He has further shown that if the droplet of blood be exposed to the air for a minute or two before being mounted on a slide, the eruption of microgametes is markedly encouraged. Similarly, Marshall has shown that it is also favoured by mixing the blood with a trace of water. I find that by combining these methods—namely, exposure to the air with slight aqueous admixture, as by breathing on the slip before applying the cover-glass—it is generally easy to procure quickly, from crescent-containing blood, specimens of the flagellated body. Probably, although I have not experimented with this object in suitable cases, the eruption of microgametes will be favoured in the non-crescent-forming parasites by similar means.
