MALARIA 



79 



of the mosquito, leaving there probably by the blood, and ultimately 

 reaching the three lobed salivary glands which communicate with the 

 base of the proboscis by means of a long duct. The parasites may be 

 seen in the cells of the salivary glands and in 

 the ducts. The parasite is now ready to enter 

 man when the mosquito bites him. 



SUMMARY OF COMPLETE LIFE-CYCLE. 



Sporozoites enter human blood corpuscles, 

 where they exhaust the Hb., form pigment, 

 become mature, and develop into either — 



(i) Schisonts, which are the segmented 

 and rosette forms. 



. Section of the stomach of an 



The hfemozom concentrates, mero- Anopheles, wiih cysts (oocysts) 



zoites form, burst the red cell and ofthe malignant tenian parasite, 



(After Grassi.) 



enter fresh ones, only to begin again 



the endogenous life-cvcle. This is k'nown as the asexual stage 

 of schizogony. 

 (2) Gaiuetes. These are crescents 

 in the subtertian form, 

 spherical bodies in the ter- 

 tian and quartan forms. 

 There are male and female 

 sexual cells, which become 

 dififerentiated in the mos- 

 quito. Microgametes break 

 ofif from the male and im- 

 pregnate tb.e female cell or 

 macrogamete. This impreg- 

 nated female is now the 



ay got e 



It begins to move 



and is now an ookinet. It 

 rests in tiie stomach wall, 

 forms a capsule, and is now 

 an oocyst. It divides into 

 daughter cells and residua' 



Four dififerent sporulation stages of malarial 

 parasites from Anoplieles tiiacu/ipeittiis, much 

 magnified, a-c, of the malignant tertian 

 parasite ; a, four lo fcur and a half days afier 

 sucking ; b and c, five to six days after suck- 

 ing ; d, of the tertian parasite, eight days 

 after sucking. (After Grassi.) 



bodies. The daughter cells 



produce around themselves needle-like bodies, perhaps io,ooa 



in one cysf, which become sporosoites. 



The oocyst ruptures, the sporozoites reach the bod\- cavitv, and 



ultimately the salivary glands, and are injected into man along the 



proboscis. These become schizonts in his blood, and renew the 



endogenous cycle of sporogony. 



It is suggested, but not proved, that the mosquito mav live in 



