THE MALARIA PARASITE 



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form crescents, and the flagellated bodies (h), which are 

 rarely seen, are developed from large pigmented parasites. 

 (2) Benign, or spring, tertian fever (Fig. 63 ; Plate 

 XXIV. a). The benign tertian parasite (Plasmodium vivax) 

 completes its asexual life- cycle in forty- eight hours, an 

 attack occurring every other day, or, reckoning the day 

 of the previous attack, every third day. In the early 

 stage it resembles the quartan, but shows much more 



FIG. 63. The benign tertian parasite : a, b, c, d, amcebulae ; 

 e, sporocyte ; /, free spores ; g, female gametocyte with so- 

 called polar bodies ; h, male gametocyte. (After Rees.) 



active amoeboid movement. The pigment-granules are 

 also finer than in the quartan, and incessantly change 

 their position. The parasite finally invades the whole 

 corpuscle, which becomes enlarged and pale. Enlarge- 

 ment of the corpuscles is a marked feature in the benign 

 tertian infection (d). 



Segmentation takes place, but is unsymmetrical (e), 

 resulting in the formation of a grape-like cluster of twelve 

 to twenty spores (/). As in the quartan, no crescentic 

 bodies are developed, and the gametocytes (g, h) are 

 similar to, but larger than, the quartan (Plate XXIV. b). 



(3) The cestivo-autumnal, malignant, pernicious, or sub- 

 tertian, fevers (Fig. 64). This parasite (Laverania malarice) 

 (or parasites, for it has been divided into three species 



