The Human Malarial Parasites 



SOS 



bite, so that his blood contains two crops of the microparasites, 

 arriving at maturity at different times. This perplexes the clinician 

 through the variety of parasitic forms in the blood and the abnormal 

 frequency of the paroxysms. 



The gametocytes of the parasite remain for some time in the red 

 corpuscles without division, but, finally become free spherical bodies. 

 Two sizes can be made out, the larger, the macrogametocyte or 

 female, the other, the microgametocyte or male. Each has proto- 

 plasm, with a tendency to take a blue-gray color and appear uni- 

 formly granular, except that at some part of the periphery of each 

 there is a circular or semicircular area that is free from granules. 

 This area is larger in the microgametocyte. 



t g h i J 



Fig. i8i. — Parasite of quartan malarial fever: o, J, c, d, enlarging* intracellular 

 parasites; e, f, g, h, segmenting parasites forming a distinct rosette from which 

 the spores separate; i, macrogametocyte; j, microgametocyte; k, sporozoit. 



II. Plasmodium Vivax (Grassi and Feletti,* 1890). — This is the 



Synonyms. — Oscillaria malarias pro parte, Laveran, 1891. Plasmodium var. 

 tertiana, Golgi, 1889. HEemamoeba vivax, Grassi et Feletti, 1890. Hasmamoeba 

 laverani var. tertiana, Labb€, 1894. Plasmodium malariae tertianum, Labb6, 

 1899. Hasmamoeba malaria; var. magna, Laveran, 1900. Hasmamoeba malariae 

 var. tertianse, Laveran, 1904. Plasmodium tertianae pro parte. Billet, 1904. 



most common of the malarial parasites of man, and occasions the 

 "benign" tertian fever. It is a large parasite, the full-grown schiz- 

 ont (meroblast), ready to form merozoits, and the gametocytes all 

 exceeding the size of the red blood-corpuscles. It matures in forty- 

 eight hours, but not with mathematic precision. In single infections 

 the greater number of the parasites are of the same age and present 

 the same appearance, but various shapes and ages may be found 

 together. In double infections, with paroxysms every day, para- 

 sites of different ages may be found. 



The youngest form in which the parasite can be observed is that 

 of a tiny ring in a red blood-corpuscle. The periphery of this 

 ring (when the blood is stained with polychrome methyene blue) 

 is outlined with blue, at one side there is a distinct blue dot, and the 

 center appears colorless and like a vacuole. The dot is usually 



"Centralbl. f. Bakt. u. Parasitenk.," 1890, vii, 396; 1891, x, 449, 481, 517- 



