HAEMOSPORIDIA 493 



almost exclusively found in the capillaries of internal organs; as 

 schizonts mature Maurer's dots appear in the infected erythrocytes; 

 when about Sju in diameter, nucleus divides repeatedly and 8-24 or 

 more small merozoites are produced ; haemozoin granules dark brown 

 or black and usuall}^ in a compact mass; infected erythrocytes are not 

 enlarged. Gametocytes: Mature forms sausage-shaped ("crescent"), 

 about 10-12 fjL by 2-3iu; appear in the peripheral blood. Macro gameto- 

 cytes stain blue and contain a compact nucleus and coarser granules, 

 grouped around nucleus; microgametccj'tes stain less deeply blue or 

 reddish, and contain a large lightly staining nucleus and scattered 

 smaller haemozoin granules. 





# 



^ f g h J 



Fig. 229. Plasmodium falciparum, X 153.3 (Original), a, three ring-forms 

 in an erythrocyte; b, a somewhat grown schizont in an erythrocyte with 

 Maurer's dotes; c-f, growng and schizogonic stages, g, h; merozoite for- 

 mation; i, macrogametocyte; j, microgametocyte. 



The subtertian fever is widely- distributed in the tropics. In the 

 subtropical region, it is more prevalent in late summer or early 

 autumn. It is relativel}^ uncommon in the temperate zone. The 

 malignancy of the fever brought about by this parasite is attributed 

 in ]3art to decreased elasticity of the infected erythrocytes which be- 

 (•( me clumped together into masses and which adhere to the walls of 

 the capillaries of internal organs especially brain, thus preventing the 

 circulation of blood through these capillaries. 



P. malariae (Laveran) (Fig. 230). The ciuartan malaria parasite; 

 schizogony in 72 hours and paroxysm every fourth day. Ring forms: 

 Similar to those of P. vivax. Growth -period: Less amoeboid, rounded; 

 in about 6-10 hours haemozoin granules begin to appear; granules 

 are dark brown; in 24 hours, schizonts are about 1/2 the diameter 

 of erythrocytes Avhich remain normal in size; schizonts often 

 stretched into "band-form" across the erythrocytes; no dots com- 

 parable with Schiiffner's or Maurer's dots. Mature and segmenting 



