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6 but in addition be able to diagnose the infection as benign tertian, quartan, or sub-tertian.

In benign tertian the red corpuscle containing the parasite is enlarged and very pale; the parasite shows very active amœboid movement for the first twenty-four hours; pigment then begins to appear in fine granules and of a lighter hue than in quartan; by full growth the pigment has acquired a coarser appearance and darker hue. The pigment granules also show active vibration. Movement gradually ceases as maturity approaches. The full-grown parasite is about the size of a normal red corpuscle. Just before or during a rigor, sporocytes form in the red corpuscles containing 15 to 20 spores, arranged irregularly around the central pigment. The gametes are spherical in shape and occur free in the plasma, having escaped from the red corpuscle before sporulation occurred. In benign tertian, and only in this type of malaria, the infected corpuscles show Schüfner's chromophilic dots.

In quartan the ring-form is smaller than the benign tertian at the same stage, and tends to assume an oblong form, lying across the corpuscle and slightly altering its shape;