284 THE PATHOGENIC HEMOSPORIDIA 



thrown out from all sides of the body and again drawn in, great vacuoles 

 appear and disappear, deep incisions cut into the periphery, to be filled 

 in immediately with the restless protoplasm. In short, this living 

 organism is a most changing and fascinating spectacle to watch, and 

 leaves the impression that the parasite is well-named 'vivax.' "^ 



Shortly after this period of activity the organism becomes quiet, 

 spherical, and rapidly undergoes the changes preparatory to mero- 

 zoite formation. The nucleus divides, as stated, by a primitive method 

 of mitosis, but with the continued division all traces of a mitotic pro- 

 cess are lost, and at the end of the second division the process is little 

 more than multiple fragmentation, division being so irregular that a 

 definite plan is excluded. The end result is a number of daughter 

 nuclei, each a small spherical granule of chromatin about which the 

 protoplasm of the parasite divides to form a small reproductive element 

 — the merozoite — while an unused residue containing the pigment and 

 crystals remains behind to be dissolved in the blood plasma and carried 

 to all parts of the system. The many merozoites thus liberated make 

 their way to fresh corpuscles and the simultaneous attack leads to the 

 characteristic symptoms of the disease. 



The young quartan parasite cannot safely be distinguished from 

 that causing tertian fever, save, perhaps, in regard to its relative 

 inactivity, a function which decreases with growth of the merozoite. 

 Its form, therefore, is more regularly spherical than that of Plasmodium 

 vivax (Plate I, Fig. 2). After about ten hours of growth (Ziemann, 

 1906) it contains fine dark brown granules of pigment. At the sixteenth 

 hour it occupies about one-quarter of the volume of the corpuscle, 

 the pigment granules being unevenly distributed about the periphery, 

 while the chromatin is less readily stained than that of the tertian 

 parasite. At the end of two days the containing blood corpuscle 

 remains only as a rim of material about the enlarged parasite, and this 

 shortly afterward disappears, the freed organism being the size of the 

 corpuscle. Characteristic merozoite formation follows, giving rise 

 to what Golgi described as the "marguerite form," due to the regular 

 segmentation of the cell body into from six to twelve merozoites 

 (Plate I, Fig. 2, 12). 



The merozoite of the organism of pernicious malaria is a very 

 minute (1.5 to 2 microns) ring-formed parasite, the rings, according to 

 Xocht, being optical illusions, due to discoid bodies with thickened 

 rims. The chromatin is in the form of a small spherical granule which 

 not infrequently elongates to a rod form and then fragments to form 

 two or three similar chromatin granules (Plate II). Double or multiple 

 infection of blood corpuscles is not infrequent, but union of those 

 separate individuals never takes place, according to Ziemann (liow- 



' Schaudinn Plasmodium vivax G. and F. der ]->reger des Tertianfiebers beiin Menschen. 

 Arb. a. d. Kais. Gesundh., 19:1902:216. 



