518 



A MANUAL OF BACTERIOLOGY 



the blastophores disappear, leaving its capsule packed with 

 large numbers (" thousands ") of free zygotoblasts. The 

 capsule then ruptures, and the zygotoblasts are poured 

 into the body-cavity of the mosquito. The " blasts " 

 measure 12-16 JUL in length, taper at each extremity, and 



The 

 Mosquito Phase 



Exogenous 

 ,or Sexual Cycle 



FIG. 61. Diagram of the asexual and sexual cycles of the 

 malaria parasite. 



possess a central nucleus (Fig. 60, e), and they make their 

 way to all parts of the body of the host, and accumulate 

 in the salivary or poison glands, whence they are dis- 

 charged by the middle stylet (hypopharynx) of the pro- 

 boscis, when the insect " bites," into the circulation of a 

 fresh vertebrate host. Here, presumably, the blasts be- 

 come attached to erythrocytes and develop into amcebulse. 



