AMGEBJE OF THE INTESTINAL TRACT. 



tinguished as a deep violet or almost black mass, 

 lying in contact with the nucleus. In stained speci- 

 mens the cytoplasmic body is always very small as 

 compared with the nucleus. 



The Encysted Stage. For the observation of 

 the process of encystment it is necessary to examine 

 fresh preparations as the cysts do not stain well. 



The organisms which are about to encyst are 

 generally smaller than the average amoebae, measur- 

 ing from 15 to 18 microns in diameter, and appear 

 more granular in structure. Amreboid motility is 

 absent and the ecto- and endoplasm are indistinguish- 

 able. If one of these organisms be watched it will 

 be observed that it suddenly begins to rotate quite 

 rapidly and that this rotation may last for an hour 

 or more, although it generally ceases within fifteen 

 minutes. The rotation is in one direction and during 

 this process the cyst wall is formed, for when it has 

 ceased it will be observed that the organism is sur- 

 rounded by a double-outlined, refractive capsule, 

 which sometimes appears slightly mammillated. Dur- 

 ing rotation the organism contracts somewhat, most 

 of the cysts measuring about 15 microns in diameter. 



In the early stage of encystment the nucleus can 

 be distinguished, situated to one side of the centre 

 of the organism, and the cytoplasmic body may also 

 be visible, lying in contact with the nucleus. Both 



