AbstractOptokinetic nystagmus was examined and registered electronystagmographically in the cases of 21 healthy subjects where the angular speed of optical stimulation was successively increased until the eyes could no longer follow the black and white bands on the optokinetic screen (the “optokinetic fusion limit”, OFL). This limit was also examined under the effect of a small dose of alcohol intravenously 0.8–1.6 g (concentration in serum of up to 5 mg/100 ml). The results showed a statistically significant decrease in OFL (P<0.01). It is pointed out that the effect of small doses of alcohol on the eye movements is similar in certain respects to that of the barbiturates. No information concerning the exact site of action of alcohol on the central nervous system may be implied from those