Ewald's second law re-evaluated.

Patients and experimental animals (cats) with one functioning horizontal semicircular canal were tested with precise rotatory stimuli. Nystagmus responses were quantified with EOG and a laboratory digital computer. After large-magnitude stimuli there was a statistically significant difference between the maximum slow component velocity of nystagmus induced by ampullopetal endolymph flow and that induced by ampullofugal endolymph flow in all patients and cats.