The pre-erythrocytic stage of Plasmodium ovals

Details of the blood and mosquito cycle of a Liberian strain of Plasmodium ovale are given, and a special form of schizont present in the blood during relapses, is described. Sporozoites derived from this strain infected a volunteer from whom a piece of liver was obtained 9 days later. Pre-erythrocytic schizonts (17) were found in sections of this piece of liver, and were roughly classified as fifth- and ninth-day forms. The fifth-day form was characterized by the exceptionally large size of the nuclei. The ninth-day form reached 85μ. in length, had an irregular lobulated contour, and when mature contained about 15,000 merozoites.