Entamoeba aulastomiNöller

Abstract

1.Entamoeba aulastomiandHexamitasp. fromHaemopis sanguisugahave been cultivated in inactivated horse-serum diluted 1 : 10 in 0·5 NaCl solution + solid sterile rice-starch, and upon an inspissated horse-serum slope covered with the liquid medium + sterile rice-starch. Cysts ofE. aulastomiappeared on or after the 9th day from subcultivation, but cysts ofHexamitahave not appeared in the cultures.2. The amoeboid phase ofE. aulastomidivides by a simple direct method, without the formation of a spindle. There is no equatorial plate. It was not possible to count the number of chromatin granules.3. The mature cyst is quadrinucleate, though occasional octonucleate cysts are found. Chromatoids are present but are absorbed before hatching. A. large glycogen vacuole is present in the uninucleate cyst. The nucleus divides by the formation of a delicate spindle but no chromosomes were found.4.E. aulastomiare not harmed by being kept at 2° C. but they die out in the 2nd subculture if kept at 30° C. and within 24 hours if kept at 37° C. The cysts also are killed at 37° C.5. If treated withN/20 HCl all amoebae are killed in less than 10 min. but the cysts are unharmed.