Effects of diethyl ether at room temperature (75[degree] F) potentiated diethyl ether (at 100[degree] F) and bis(trifluoroethyl) ether (Indoklon) administered to mice at several intervals following training on a single-trial avoidance problem were compared. Temperature of ether was found to be a critical factor. No memory impairment was found if ether was administered at room temperature, but memory was impaired with potentiated-ether treatment administered as much as 24 hr. subsequent to training. Indokion was found to have interfering effects when administered as much as 4 hr. posttraining. Results support a consolidation theory of memory and indicate that severity of treatment may extend duration of amnesic effect.