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I] The former is male, the latter female. The protoplasm of the male parasite stains more deeply, and its nucleus is larger than that of the female parasite.

The more immature forms of the crescent are said to begin to be recognizable in the spleen and bone marrow about the fourth day after a subtertian malarial attack commences. At first, according to Bastianelli and Bignami, they are minute, highly refringent amœboid bodies. They are rarely encountered in peripheral blood; there the crescent body does not begin to show itself till it approaches maturity, about a week after the first crop of amœboid parasites associated with the fever paroxysm has appeared.

Fig. 7.—Evolution of the flagellated body from the crescent.

Formation of the flagellated body.— Ordinarily, if a number of crescent bodies are kept for a time under observation on the microscope slide a certain proportion of them will be seen slowly, or more rapidly, to undergo change of shape, gradually becoming converted into squat crescents, then into oval bodies, and then into spheres (Fig. 7, a, b, c), whilst the remains of the enclosing blood corpuscle fall to pieces or melt away. The remains of the blood corpuscle are often seen as a small, slightly hæmoglobin-tinted globule lying in contact with or near the parasite. The crescent-derived spheres are of two types in correspondence with the sex of the particular crescent from which they originate, some—the male—having hyaline, others—the female having