R. T. Wells 
205 
distinguished two types of intestinal amoebae (i) Entamoeba coli, a 
harmless commensal and (ii) E. histolytica, identified by him with that 
previously described and figured by Jurgens (1902) as the causal 
organism in three cases of dysentery originating in China. Schaudinn 
gave it as his opinion that cultures of parasitic amoebae were not 
obtainable. He insisted on the necessity of consecutive study of the 
morphology and life-cycle of parasitic protozoa in their ordinary modes 
of life. He therefore based the differentiation of these two types on 
the features as observed in the natural surroundings of the amoebae, 
i.e. the intestinal contents and also, in the case of E. histolytica, in the 
intestinal walls of men who had died of dysentery and of experimentally 
infected cats. 
Viereck (1907), Hartmann (1908), and Werner (1908), following 
Schaudinn’s methods of observation, described another species of amoeba 
in the stools from cases of dysentery, .E". tetragena,sX\\e(\. to E. histolytica. 
Viereck (1907) considered that the natural occurrence of pathogenic 
amoebae in water had not been convincingly demonstrated and that 
such amoebae had not been proved to multiply on artificial media; 
on the contrary, he emphasised the fact that amoebae in stools 
appear to die off rapidly after their discharge from the body. Werner 
(1908) attempted to obtain multiplication of parasitic amoebae by 
transferring to fucus-agar-medium fresh stools containing vegetative 
forms of E. histolytica and E. tetragena ; in no case did he see multipli¬ 
cation of these amoebae (the number of observations is not stated); 
on the other hand he found, on the agar medium, growth and encyst- 
raent of what was apparently a different species of amoeba; this 
organism he was inclined to identify with Amoeba Umax (Vahlkarapf), 
a free living form of wide distribution. He showed that, when cysts of 
A. Umax were ingested by house-flies, such cysts passed through the 
alimentary canal apparently unchanged, so that they germinated when 
the faeces of the infected fly were transferred to a suitable medium 
such as the agar used in his experiments. Werner suggested that the 
amoebae appearing in cultures from human faeces might have had a 
similar history. 
In marked opposition to the findings of the above observers are 
those of Musgrave and Clegg (1906, 1907), Lesage (1905), Walker 
(1908), and Noc (1909). 
In 1904 Musgrave, and in 1906 Musgrave and Clegg, using an agar 
medium with an alkalinity of 1 "/o. cultivated amoebae from the stools 
in cases of dysentery inv Manilla, from water, soil and a variety of 
