1920] Kofoid: Nomenclature of Human Intestinal Flagellates 147 



DISCUSSION 

 Cebcomonas Not as Yet Proved to be a Human Parasite 



This genus was originally described by Dujardin (1841) for free- 

 living flagellates from infusions. It was characterized by the posses- 

 sion of one anterior flagellum and a posterior prolongation. It wa.s 

 therefore natural that human parasitic flagellates in which there was 

 seemingly one anterior flagellum and a caudal process should be 

 referred to this genus. In the clinical literature to the present day, 

 this genus is a convenient catchall for most inadequately determined 

 flagellates of man. This reference results in part from the fact that 

 the first flagellate to be described from the intestine of man was called 

 Cercomonas by Davaine (1854). 



The genus Cercomonas, however, has not been critically established 

 as a parasite of man by any of the many extensive surveys of the 

 protozoan intestinal fauna which have been made in recent years in 

 connection with the World War. No competent protozoologist has 

 described, figured, and critically discu.ssed any Cercomonas as an 

 undoubted parasite of man in connection with these tens of thousands 

 of stool examinations. There are, however, many reports of occurrences 

 of Cercomonas and of Cercomonas hominis, and some of C. parva and 

 C. crassicauda, but they all fall, in my opinion, into some one of the 

 following categories. 



1. ITncritieal allocations to Cercom-onas of some flagellate not 

 assignable to Trichomonas or Giardia. In most cases, if not all, the 

 organism present and thus reported was Chilomastix davainei 

 Moquin-Tandon, a name which we adopt in lieu of C. mesnili 

 (Wenyon). This conclusion rests upon statistical evidence such 

 as that of Matthews and Smith (1919) who compile the results of 

 23,024 stool examinations of 4068 persons^ mainly dysenteries, with 

 669 infections of Giardia intestinalis, or 16.4 per cent, 148 of Chilo- 

 mastix mesnili, or 3.6 per cent, and 29 of Tricliomonas intestinalis, or 

 0.7 per cent; and that of Kofoid (1920), who compiles the results of 

 3218 examinations of 2876 soldiers, with 168 Giardia intestinalis, or 

 5.9 per cent, 117 Chilomastix mesnili or 4.1 per cent, 6 Tricliomonas 

 intestinalis or 0.2 per cent, and 4 occurrences of Embadomonas intes- 

 tinalis, and 8 of Tricercomonas intestinalis. It thus appears that, 

 according to statistical probabilities, any flagellate in addition to 



