274 SPOROZOA. 



Plasmodium malarias, Minchin, 1903, pp. 243, 267 ; 1912, p. 358. 

 fThe Quartan Parasite, Row, 1917, p. 392, pis. xviii, xix. 



Plasmodium malarise, Castellani & Chalmers, 1919, pp. 512-13 ; 

 Muhlens, 1921, pp. 1499-502, pi. xxxi, figs. 9-19 ; pi. xxxii, 

 figs. 16-25 ; pi. xxxiii, figs. 1, 3 ; Hegner & Taliaferro, 1924, 

 pp. 326-7, 330, 331, pi. ii, figs. 1-8 ; Craig, 1926, pp. 419-31, 

 figs. 72, 73 ; Wenyon, 1926, pp. 942-4, pi. xiii, figs. 1-15 ; 

 Hehir, 1927, pp. 162-4, pi. ix, figs. 1-3 ; pi. xi, figs. 58-75. 

 ■^Plasmodium, maJarisR, Knowles, 1927, pp. 12-14, pi. ii, figs. 1-22 ; 

 1928, pp. 389-92, pi. xii. 



Plasmodium malarise, Reichenow, 1929, pp. 1004-6, fig. 975, m-p, 

 987-90; Kudo, 1931, p. 287, fig. 121, o-m ; Calkins, 1933, 

 pp. 238, 406-10, fig. 124 ; pi. i, figs. 7-12 ; Brumpt, 1936, 

 pp. 424-30, pi. ii, figs. 19-36; Coatney & Roudabusb, 1936, 

 p. 339. 



The Cycle in Man. — The cycle in man is very similar to 

 that of Laverania malarias and Plasmodium vivax. " Rings " 

 are of the same size as of P. vivax and have a diameter of about 

 one-third to a half that of the red blood-corpuscle. Cytoplasm 

 is denser and stains more deeply, and shows little amoeboid 

 activity during growth. Pigment granules are coarse and of 

 a darker brown colour. The organism often shows a tendency 

 to be stretched as a band across the diameter of the corpuscle. 

 These " band forms " are more frequently seen in this species. 

 The band may be narrow or almost as broad as long. The 

 infected red corpuscle is no larger, and may even be smaller 

 than the normal corpuscle, and may also be deeper in colour 

 in stained films ; and as a rule no Schiiffner's or Maurer's dots 

 are found. Schizont reaches its full size in about sixty 

 hours and schizogony occurs every seventy-two hours. The 

 fully grown schizont is circular in outhne, and almost com- 

 pletely fills the corpuscle, the dark pigment granules forming 

 a central mass. Schizogony results in the production of six 

 to twelve merozoites that are arranged ia a single ring or 

 " rosette." All phases of schizogony take place in the peri- 

 pheral blood. The gametocytes are oval or spherical in outHne, 

 and completely fill the red blood- corpuscles. The distinguishing 

 characteristics of microgametocytes and macrogametocytes 

 are similar to those in P. vivax, the female staining more deeply 

 blue and having a more compact nucleus. The pigment 

 granules are scattered irregularly in the cytoplasm. 



The Cycle in the Mosquito. — The development in the Ano- 

 phehne mosquito is very similar to that of P. vivax, but the 

 various stages can be distinguished from those of P. vivax 

 by the pigment being dark brown or black. In this respect 

 they resemble those of Laverania malarias. 



Remarks. — Two " rings " or partially developed tropho- 

 zoites may sometimes be found in the same corpuscle, but are 

 less common than in P. vivax infections. Two mature 

 gametocytes in an enlarged cell, as also a gametocyte and a 

 schizont, have also been found to occur in the same corpuscle. 



