652 FAMILY: TEICHOMONADID^ 



in the stool, and also in cultures in media containing rabbit blood. The 

 presence of included red cells has been advanced as an argument in favour 

 of the pathogenicity of this flagellate, but there is no reason to suppose 

 that they have been taken up by the flagellates anywhere than in the 

 lumen of the gut. In the case of Entamoeba histolytica, it is probable that 

 the red cells are ingested by the amoebae while they are still in the tissues. 



Cultivation. — Several observers have cultivated T. Jioininis. Escomel 

 (1913) stated that he had obtained a culture in a vegetable medium, but 

 there was no evidence that he had done anything more than keep the 

 flagellates alive, as sometimes happens, for many days in the liquid faeces 

 themselves. Lynch (1915a, 1915c) was able to keep T. hotninis, as well 

 as the other human species, alive for some days in acid bouillon. In the 

 case of T. hominis a few subcultures were made, and it seemed evident that 

 multiplication had taken place- Boyd (1918, 1919) was more successful 

 by using a saline suspension of fresh faeces in which T. hominis was taken 

 through seven subcultures during sixty-five days, Ohira and Noguchi 

 (1917) cultivated T. hotninis (? T. elongata) in a mixture of ascitic fluid and 

 Ringer's solution. Active multiplication took place in the deeper parts of 

 this medium and by subculture every forty-eight hours when the tubes 

 were kept at 23° to 27° C, or every twenty-four hours when, at 37° C, 

 the flagellates were kept alive indefinitely. Barret, who has successfully 

 cultivated Balantidium coli and Blastocystis in a 10 per cent, solution of 

 inactivated human blood-serum in 0-5 per cent, sodium chloride solution, 

 informs the writer that he has cultivated T. hotninis in this medium and 

 taken it through thirty subcultures. The writer has successfully cultivated 

 the flagellate and maintained it by subculture in Hogue's egg medium at a 

 temperature of 24° C. Bacterial growth takes place rapidly, and to keep 

 the flagellates alive it is necessary to subculture every week. At higher 

 temperatures subculture must be made more frequently. The culture 

 method has been used for diagnosis purposes by Hegner and Becker (1922) 

 and Reichenow (1923). Boeck and Drbohlav (1925), and Thomson, J. G. 

 and Robertson(1925),have cultivated T. hominis inBoeck's L.E.S. medium. 



Method of Infection. — The question of the method of infection with 

 T. hotninis presents some difficulties. Definite encysted forms have not 

 been discovered in man. If infection occurs from man to man, and if it is 

 true that cysts do not occur, then it must be assumed that infection takes 

 place by ingestion of the active flagellates themselves, which are known to 

 survive for a considerable time outside the body. It was shown by the 

 writer and O'Connor (1917) in Egypt that flies fed on faeces containing 

 T. hotninis deposited in their dejecta live flagellates five minutes later. 

 In this manner, food or drink could readily become contaminated with the 

 living organisms. 



