EMBADOMONAS INTESTINALIS 619 



resembles those of Chilomastix mesnili, but is smaller. Quite recently the 

 writer has examined cysts of E. intestinalis, which have been fixed in osmic 

 acid vapour and stained by Leishman stain. In these preparations there 

 is a central red granule surrounded by a blue ring, which undoubtedly 

 represents the nucleus and its karyosome. The two lines which extend 

 the whole length of the cyst probably represent the margins of the cyto- 

 stome, and not the nuclear membrane. The dumb-bell-shaped structures 

 mentioned above may have been dividing karyosomes. 



In one of the two infections seen by the writer and O'Connor (1917) 

 in Egypt, E. intestinalis persisted for one and a half months. Though the 

 flagellates were seen in diarrhoeic conditions, there was no evidence that 

 they were the actual cause of the trouble. 



Hogue (19216) reports the successful culture of E. intestinalis in a 

 medium made by cooking the white of one egg with 100 c.c. of 0-7 per cent, 

 solution of sodium chloride. During heating, the mixture is constantly 

 shaken. It is then filtered and placed in test-tubes, after which it is 

 autoclaved. By subculture every other day, the flagellate was kept alive 

 for over eight weeks at a temperature of 35° C. In the cultures the 

 flagellates multiply by binary fission, and also produce the typical cysts. 

 The writer (1921a) has succeeded in cultivating E. intestinalis as also 

 forms from the guinea-pig, rat, tortoise, and frog, not only in Hogue's 

 egg medium, but also in a soft rabbit blood-agar medium. The cultures 

 were maintained both at 24° and 30° C. 



Faust and Wassell (1921) described as E. sinensis a flagellate seen 

 by them in nine cases of diarrhoea in North China. A further account 

 of the organism has been published by Faust (1922). The average size is 

 given as 14 by 4-2 microns, but longer forms up to 20 microns were seen. 

 From the description and figures it appears that the two flagella are of 

 equal length and thickness (Fig. 255, 20-22). The encysted forms, how- 

 ever, correspond in shape and size with those of E. intestinalis. In a case 

 of E. intestinalis (that of Broughton-Alcock and Thomson noted above) 

 which the writer had an opportunity of studying, flagellates up to 17 microns 

 in length were seen. The larger forms were more frequently encountered 

 in cultures. The statement made by Faust and Wassell that the flagella 

 of their species were ec^ual in length and thickness requires confirmation, 

 for in all the forms examined by the writer (man, guinea-pig, rat, tortoise, 

 frog) the cytostomal flagellum has been thicker and shorter than the 

 other. It seems to the writer that it is exceedingly doubtful if E. sinensis 

 is a distinct species from E. intestinalis, especially as the encysted forms 

 are alike. The flagellate described as Enteromonas Bengalensis by Chaterjee 

 (1919) may be E. intestinalis (see p. 307). 



