TRICHOMONAS HOMINIS! VIABILITY 



between the ages of 6 months and 6 years which may 

 have had some influence on the results obtained. Paulson 

 and Andrews (1927) also used fresh stools in their 

 work and obtained an incidence of 4.3 per cent in 210 

 persons in Baltimore which is high when compared with 

 the results reported by Boeck and Stiles. The ease of 

 manipulation and uniformly excellent results obtained by 

 various investigators indicate that the fear expressed by 

 Lynch (1924b) that the culture method in inexpert 

 hands "could only increase the existing confusion" is 

 without foundation. 



Viability of trophozoites. Trichomonas hominis is very 

 resistant in the trophozoite stage in fecal material. Heg- 

 ner and Becker (1922) kept an infected stool in a covered 

 glass container and inoculated culture tubes at intervals 

 for four days ; positive cultures were obtained 79 hours 

 but not 95 or 103 hours after the stool was passed. 

 Smears were positive 37}^ hours but not 47 hours or 

 more after defecation. Pentatrichomonas ardindelteiU, 

 according to Kofoid and Swezy (1924b), will remain 

 alive in liquid stools for 24 days. These flagellates, there- 

 fore, have considerable opportunity to reach the food or 

 drink of man so long as the fecal material remains moist. 

 That high temperatures do not destroy trichomonads in 

 nature is evident from the experiments of Pringault 

 (1920) and Andrews (1926a). Pringault found that T. 

 (intestinalis) hominis dies in 2 hours and 30 minutes 

 at 0° C, in 45 minutes at 50° C, and in 7 minutes at 

 65° C. ; and Andrews showed the thermal death point 

 of Pentatrichomonas ardindelteiU and Trichomonas 



145 



