10 PARASITIC AMOEBAE OF MAN. 



all be considered in this contribution, the data con- 

 cerning each being given so far as it is on record. 

 The most important new species was described by 

 Viereck in 1906, who found an amoeba, differing from 

 any heretofore described, in cases of dysentery, to 

 which he gave the name Entamoeba tetragena. His 

 observations have been confirmed by Hartmann, 

 Prowazek and myself, and there can be no doubt but 

 that this is a distinct species of pathogenic amoeba. In 

 the same year I described another species of amoeba 

 possessing both a flagellate and an amoeboid cycle 

 of development to which the name " Par amoeba 

 hominis" was given. In 1904 Prowazek described a 

 species occurring in the mouth to which he gave the 

 name Entamoeba buccalis. 



In addition to the species just mentioned several 

 others have been described, i.e., Entamoeba tropicalis, 

 studied by Lesage in 1908; Entamoeba minuta, de- 

 scribed by Elmassian in 1909; and Entamoeba nip- 

 ponica, described by Koidzumi in the same year. In 

 addition to these there are a few so-called species 

 which possess little interest or scientific value by 

 reason of imperfect observation or description. 



From this summary of the history of the develop- 

 ment of our knowledge regarding the parasitic 

 amoebse of man it will be noted that it has been of 

 slow growth, over fifty years having elapsed since 



