FIG. 101. The Life Cycle of the Malaria-parasite. 1, the organism (sporozoite) in- 

 troduced by the mosquito bite into the human blood ; 2, the same free in the blood ; 

 3-5, changes which it undergoes within the red blood-cells; 6, spores (merozoites) 

 formed by division, with the attendant destruction of the blood-cell ; this cycle 2-6 may 

 be repeated many times, but eventually spores develop in the blood-cells into sexual 

 forms ; 7, 8, 9, development of a macrogamete or female element ; 7a, 8a, 9a, 96, devel- 

 opment of microgamete or male element ; 10, conjugation of the two sexual cells ; 11, the 

 resultant zygote ; 12, zygote that has entered the body of the mosquito and has worked its 

 way to the wall of the latter's stomach, it lies at the base of two cells; 13-16, trans- 

 formation of zygote into an oocyst filled with spores; 17, adult female malarial mos- 

 quito (Anopheles), head of the male below; 19, larva; 20, pupa; 21, stomach of 

 mosquito, showing cysts produced by the parasites ; 22, cross-section of salivary gland 

 of mosquito, showing the cells full of spores which have wandered in from the cysts of 

 21 and are now ready to pass into the blood with the bite of the mosquito. 



