GENUS: CRAIGIA 295 



the amrebso and the flagellates were of the dimensions given by this 

 observer for the corresponding stages of C. hominis. In these pre- 

 parations no other Protozoa were present, so it seems probable that these 

 had been regarded as C. hominis. When Barlow's description of Craigia 

 appeared, the writer asked him for preparations, but was informed that none 

 was available, and the films he had prepared were so poorly stained that he 

 had not been able to recognize the nature of the organism, but that Craig, 

 to whom he had sent the films, had been able to convince himself that 

 Craigia was present. At the writer's request Dr. Newham, during a recent 

 visit to Honduras, made films from a number of cases showing intestinal 

 flagellates. The writer has examined these, and could find only the well- 



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1 Z 3 



Fio. 139.—Craigia migrans (x ca. 3,000). (After Kofotd and Swezt, 1921.) 



1. Rounded type of flagellate. 2. Elongate type of flagellate. 3. Encysted form. 



known forms. In several of the films Chilomastix was present. This flagel- 

 late, which is evidently quite common in Honduras, was not identified by 

 Barlow, so it is not improbable that he mistook this organism for C. hominis. 

 The extensive investigations made during the war have cleared up 

 many doubtful points in connection with the intestinal Protozoa of man, 

 but neither C. hominis nor C. ynigrans has been rediscovered. The 

 writer has long held the opinion that no such parasites of the human 

 intestine exist, and in this conclusion he is in agreement with Dobell 

 (1919). Kofoid and Swezy (19216), as stated above, have claimed to have 

 observed cases of infection with both species of Craigia. The parasite 

 seen by these observers does not in its amoeboid phase resemble E. coli in 

 any way, while in the flagellated stage the flagellum is an exceedingly fine 

 structure which is difficult to detect, and does not show the least resem- 

 blance to the tail -like processes figured by Craig. The organism corre- 



