xiii, b, 5 Haughwout: Flagellated and Ciliated Protozoa 239 



the presence of Entamoeba histolytica, and three others were 

 positive for an Entamoeba of an undetermined species. 



Barlow found that indiscretions of diet or the administration 

 of cathartics would invariably cause the appearance of the 

 parasites, and he concluded that the increase in numbers was 

 the result and not a cause of the diarrhoea, and that the augmen- 

 tation was dependent upon more favorable conditions for growth 

 provided by the fluid stools. His study was based on Trichomo- 

 nas, but it apparently was of the tetratrichomonad type, for he 

 described his organism as having four flagella. As he was 

 unable to demonstrate the axostyle in the examination of several 

 hundred specimens, it is barely possible he was dealing with 

 Macrostoma or some other species. 



Woodcock (52) believes that Trichomonas, Lamblia, and Batan- 

 tidium, like Entamoeba histolytica, may occur without causing 

 symptoms, "but on the other hand they are potentially harmful." 

 He describes trichomonad stools as loose or thin diarrhoeal, con- 

 taining sometimes a little mucus and scattered pus cells. In a 

 few of his cases manifestly dysenteric stools contained the para- 

 sites. The great majority of the stools were never of a dysen- 

 teric character, these being cases of pure Trichomonas infection. 

 The diarrhoea, however, was troublesome and chronic and often 

 resisted all treatment. 



Castellani,(6) discussing the intestinal flagellates as a group, 

 thinks that when present in small numbers they are probably 

 harmless, but in large numbers they may give rise to symptoms. 

 Lamblia he regards as the most pathogenic of all. The patient, 

 he says, complains of the diarrhoea, and the yellowish stools may 

 contain a little mucus. He has never found blood nor pus. 



Wenyon(50) is another worker who states his belief that diar- 

 rhoea favors the multiplication of intestinal flagellates. Person- 

 ally I have often seen them in formed as well as in diarrhoeal 

 stools, sometimes associated with Blastocystis or entamoebic in- 

 fections, but more often not. I have seen only two pure infec- 

 tions with Blastocystis. 



All this raises the question as to how the reactions of the 

 environment affect the mode of life of the parasite in regard 

 to nutrition and reproduction. Protozoologists are familiar with 

 the remarkable powers of adaptation shown by both the free- 

 living and the parasitic Protozoa. The changes in mode of life 

 and reproduction that follow the transfer of the malarial para- 

 site from the warm environment of the human blood stream to 

 the cold and otherwise different environment of the gut of 



