PARASITIC AMOEBAE OF MAN. 



soon disappear, however, and the cyst becomes filled 

 with refractive granules due to the division of the 

 cytoplasmic body and the nucleus. At a later stage 

 of development the cysts appear to be crowded with 

 small spherical bodies, which are refractive and some- 

 times appear to move about within the cyst wall, but 

 this motion may be molecular in nature. At the very 

 latest stage of development within the cyst, the out- 

 line of the young flagellates may be distinguished, 

 most of them appearing spherical in shape and a 

 dull gray in color, but the flagellum cannot be dis- 

 tinguished while they are still contained within the 

 cyst. 



The Flagellate Stage. I have not been able to 

 observe the escape of the young flagellates from the 

 mother cyst, but groups of these organisms are fre- 

 quently observed, surrounded by the ruptured cyst 

 wall and arranged in spherical masses corresponding 

 in size with the original cyst. It is very evident that 

 these organisms have developed within the cyst and 

 they very soon assume the typical appearance 

 presented by the flagellate stage of the parasite. 



In the youngest stage of development, i.e., just 

 after liberation from the cyst, the swarm-spores do 

 not appear to possess a flagellum; they are very 

 small, measuring from 3 to 6 microns in diameter, 

 are spherical in shape, and have a finely granular 



