DIFFERENTIATION OF HUMAN AMCEBiE 253 



belli, is almost conclusive evidence of the amojbae being E. coli. It 

 should be remembered, however, that dying or dead E. histolytica may be 

 invaded by bacteria of all kinds, while occasionally a particular type of 

 body, such as the spores of a bacillus, may be taken up by apparently 

 healthy E. histolytica. All the intestinal amoebse of man, as well as the 

 free-living amoebae, are liable to invasion by the vegetable organism 

 Sjphcerita, a name given to it by Dangeard (1886), who saw it in a Heliozoan. 

 It was seen by the writer (1907) in E. muris of mice. It has the 

 appearance of spherical masses of coccus-like bodies which are highly 

 refringent in the 

 living condition. In 

 films stained by iron 

 haematoxylin they are 

 black. They occur in 

 vacuoles in the cyto- 

 plasm (Fig. Ill, 4). 

 A less common para- 

 site of similar appear- 

 ance is one which 

 occurs within the 

 nuclear membrane. 

 It was named Nucleo- 

 fhaga by Dangeard O^ 

 (1896), who saw it 



in the nuclei of free- ^ _ 



living amoebae. Noller 



(19^1) has described Yig. 118. — Btastocystis hominis from Human Faeces fixed 

 its occurrence in the in Sciiaudinn's Fluid and stained with Iron H.ema- 



nuclei of E. nana and toxylin ( x 2,000). (Original.) 



/. biltschlii. ^^ addition to the nuclei the thin layer of cytoplasm surrounding the 



. largecentral vacuole contains dark staining granules of volutin. 



It IS difficult to 1-7, Ordinary forms; 8, dividing form. 



give any rules for the 



separation of amoebae or their cysts from other structures in faeces. Blasto- 

 cystis hominis Brumpt, 1912, is very commonly present, and varies con- 

 siderably in size (Fig. 118). It has a large central vacuole, while the 

 cytoplasm is reduced to a thin layer in which one or two small nuclei lie at 

 each pole of the cyst. Refractile globules of volutin which may be present 

 in the cytoplasm must not be mistaken for the nuclei, which are much less 

 distinct. The organism has a much more delicate appearance, and is 

 generally less refractile than the amoebic cysts. Usually the central vacuole 

 contains non-refractile material; at other times it contains a highly refrac- 

 tile body which may have a yellowish or brownish tint. Blastocystis may 



