/ff 



FIG. 273. Life history of malaria parasite, Laverania falciparum. I, sporozoite, intro- 

 duced by mosquito into human blood; the sporozoite becomes a schizont. 2, young schi- 

 zont, which enters a red blood corpuscle. 3, young schizont in a red blood corpuscle. 4, 

 full-grown schizont, containing numerous granules of melanin. 5, nuclear division prepara- 

 tory to sporulation. 6, spores, or merozoites, derived from a single mother-cell. 7, young 

 macrogametocyte (female), derived from a merozoite and situated in a red blood corpuscle. 

 7a, young microgametocyte (male) derived from a merozoite. 8, full-grown macrogameto- 

 cyte. 8a, full-grown microgametocyte. In stages 8 and 8a the parasite is taken into the 

 stomach of a mosquito; or else remains in the human blood. 9, mature macrogamete, 

 capable of fertilization; the round black extruded object may probably be termed a "polar 

 body." pa, mature microgametocyte, preparatory to forming microgametes. gb, resting 

 cell, bearing six flagellate microgametes (male). 10, fertilization of a macrogamete by a 

 motile microgamete. The macrogamete next becomes an ookinete. n, ookinete, or 

 wandering cell, which penetrates into the wall of the stomach of the mosquito. 12, 

 ookinete in the outer region of the wall of the stomach, i.e., next to the body cavity. 13, 

 young oocyst, derived from the ookinete. 14, oocyst, containing sporoblasts, which are to 

 develop into sporozoites. 15, older oocyst. 16, mature oocyst, containing sporozoites, 

 which are liberated into the body cavity of the mosquito and carried along in the blood 

 of the insect. 17, transverse section of salivary gland of an Anopheles mosquito, showing 

 sporozoites of the malaria parasite in the gland cells surrounding the central canal. 



1-6 illustrate schizogony (asexual production of spores); 7-16, sporogony (sexual pro- 

 duction of spores). 



After GRASS: and LEUCKART, by permission of Dr. Carl Chun. 



249 



