LOESCHIA 



E..minuia, which is to-day generally considered to be a stage of 

 L. histolytica. 



In 1911 there appeared a valuable paper by Walker, in which he 

 distinguished only L. coli and L. histolytica, but the latter was 

 considered to have ' a tetragena stage,' a fact accepted to-day. 

 He said that L. histolytica was hyaline, feebly refrangent, with active 

 motility, feebly staining cytoplasm, and an indistinct nucleus, 

 with a relative paucity of chromatin, which was present as a barely 

 perceptible layer on the inner surface of the nuclear membrane, 



Fig. 53. — Diagram of the Life-Cycles of Loeschia histolytica Schaudinn. 



(Constructed from Hartmann's drawings in the Archiv fiir 

 Schiffs- und Tropen-Hygiene.) 



I, Fully grown parasite; 2-6, stages in encystment and nuclear division. 



with or without a few fragments scattered in the nuclear network 

 (histolytica stage), or as a more extensive but loose peripheral 

 granular layer and a loose central karyosome (tetragena stage). 

 All cysts were quadrinucleate. 



In the same year Whitmore and Akashi published contributions. 



In 1912 Hartmann came to the conclusion that there really was 

 only one pathogenic amoeba in man, and that this was E. tetragena, 

 the morphology and development of which he studied. 



This was the view which we adopted in our second edition, and 

 Hartmann's observations may be gathered from the following 

 account: — 



