292 BACTERIOLOGY FOR NURSES 



fresh corpuscles and begin anew their cycle of development. The 

 typical malarial chill appears just at the time of the freeing of the 

 merozoites (Fig. 45). 



tfot all of the full-grown parasites segment and produce mero- 

 zoites; a certain number become gametocytes or sexual forms. 

 The female cells, the macrogametocytes, are the larger, measuring 

 about 12 fi, and containing coarse grains of pigment; the male 

 cells, microgametocytes, are smaller and stain more faintly. In 





FIG. 45. Malarial Parasite. A, Development of Merozoites; B, Gametocytes. 



the circulating blood of human beings the gametocytes show no 

 further change, but when the blood is shed or after it is swallowed 

 by a mosquito an interesting series of changes may be observed. 



Sexual Phase (Sporogeny). The same phenomena which 

 occur within the body of a mosquito may be observed in freshly 

 drawn infected blood examined under the microscope. In the 

 rounded male cell a vibratory movement of the chromatic granules 

 can be seen and very soon four to eight long flagella-like appendages 

 emerge. These delicate filaments, which represent the sperm cells 



