[Amphizoic stage of free amoebae, myth or reality (could oxygen be the limiting factor?)].

We did not succeed to show of true free living amoebic parasites in stools of 207 micromammals from Finistere area, while on the other side 17 stool cultures were positive. To explain this failure, we exposed A. culbertsoni to oxygen: the trophozoit stage offers astonishing resistance during 1 to 6 hours and under 1 to 36 ATA pressures. Thus the lack of intestinal amphizoic free living amoebae could be explained by their very high affinity for oxygen and their lack of growth in a medium without this gas.