The malarial fevers, haemoglobinuric fever and the blood protozoa of man . odium, or Plasmodium falciparum, appears first within theinfected red corpuscle as a round or oval hyalin ring or disk, but even in the 38 THE ETIOLOGY OF THE MALARIAL FEVERS. earliest stage of development of the schizont important differences are to benoted between this and the quotidian species. The young tertian plasmodiaare considerable larger than those of the quotidian species, occupying fromone-quarter to one-third of the infected red cell, which, while smaller thanthe normal cells surrounding it, and greenish in
The malarial fevers, haemoglobinuric fever and the blood protozoa of man . odium, or Plasmodium falciparum, appears first within theinfected red corpuscle as a round or oval hyalin ring or disk, but even in the 38 THE ETIOLOGY OF THE MALARIAL FEVERS. earliest stage of development of the schizont important differences are to benoted between this and the quotidian species. The young tertian plasmodiaare considerable larger than those of the quotidian species, occupying fromone-quarter to one-third of the infected red cell, which, while smaller thanthe normal cells surrounding it, and greenish in color, is not shrunken andwrinkled at this early stage of development as in quotidian infections. Thering forms are irregular in outline, one portion of the ring being broaderthan the remainder, giving rise to the so-called signet-ring appearance,never observed in quotidian infections. The organism is more highly refractiveand sharply outlined, and the amoeboid motion is more sluggish and moreeasily observed. The ring form is often lost, a clear, hyalin disk Fig. 9.—Plasmodium falciparum tertianum. (Aestivo-autumnal tertian.) Two ringforms and two young gametes. Photomicrograph, X 1200. Very rarely is more than one parasite seen in a single corpuscle, except whenintracorpuscular conjugation, a process common to all malarial plasmodia,is present. The changes in the outline of the plasmodium are very marked,and it is much more easily recognized than, is the quotidian plasmodium(see Fig. 9). In the course of from 20 to 24 hours the hyalin forms become pigmented,the pigment occurring in the form of very fine, reddish-brown granules some-what resembling those found in the benign tertian plasmodium. The pigmentis in larger amount than in the quotidian plasmodium, is sluggishly motile, andmakes its appearance while the plasmodia are ring-shaped, being situatedwithin the enlarged area, thus giving the organisms a still greater resemblanceto a signet ring. The organism gr
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