LIFE HISTORY OF THE MALARIA PARASITE 483 



patient recovers or succumbs. Some of the parasites undergo 

 certain changes which differentiate them into sex cells. Since all 

 the parasites were injected into the blood at approximately the 

 same time, and since it takes each one just so long to grow, form 

 spores, excrete wastes, and escape from the corpuscle, all, with 

 their wastes, are ejected into the blood stream at one time. 

 Therefore, the chills and fever occur at intermittent periods. 



When a mosquito bites a patient, it takes in the malarial 

 patient's blood with the plasmodia which developed into two 

 types of sex cells. These undergo divisions and changes. Study 

 the diagram (p. 484) and note that some cells take different forms. 

 Some of them become male cells, others, female cells. Fertiliza- 



anopheles mosejuito 



Culex, the house mosquito, differs in appearance from Anopheles, the malarial mosquito. 

 Compare the different stages of growth in the life of these two insects. 



tion occurs in the stomach of the mosquito by the union of the 

 male and female plasmodia. The fertilized cells bore into the 



