The first irritative and then the second paralytic nystagmus are observed after introducing KCl solusion to the tympanic cavity of ginea pigs. This is thought to be induced by the change of K+ consentration delivered through the round window to the labyrinth. By measuring the time course of the K+ activity change in the perilymph using the K+ specific microelectrade method, the following result was obtained: K+ activity of perilymph increased so rapidly to higher degree in 20 minutes after introducing KCl solusion and then decreased gradually to the half of the peak in 120 minues.
