26 



MALARIA 



marked changes, extruding from three to six flagella 

 often in a few minutes ; each of these flagella breaks 

 loose from the parent body, forming the male gamete 

 (spermatozoon), which in the stomach of the mosquito 

 fertilizes the female gamete, forming the ookinet (also 

 called vermicule), in which stage the wall of the stomach 

 is penetrated and a position is taken up just beneath 

 the membrane forming the outer stom- 

 ach lining. In this position the para- 

 sites grow enormously, forming cysts 

 (Fig. 5) in which many nuclei appear 

 in four or five days ; these give rise to 

 myriads (thousands) of spindle-shaped 

 bodies (sporozoites) which are in from 

 midgut (stomac°htof twenty-four to forty-eight hours more 



Anopheles mosquito, ^ j j t th fc J cavitV of the ITLOS- 



with cysts of malaria J J 



EfZJSSZZ. q uito - Thc sporozoites eventually col- 



Manual") Lab ° ratory ^ ect m tne salivary glands and are 

 injected with the saliva into the cir- 

 culation of the next person bitten. The time required 

 for the sexual cycle is from seven to ten days under 

 favorable temperature conditions. 



With the introduction of the sporozoites into the blood 

 of a human being the asexual cycle begins, and the 

 victim may show clinical symptoms of malaria in ten 

 to twelve days in cestivo-autumnal fever after being 

 bitten, and in five or six days in benign tertian. The 

 red blood corpuscles are at once attacked, the parasites 

 gaining entrance and growing, full asexual growth 



