It has long been known that minor symptoms of hyperexcitability of neuromuscular activity, such as twitchings of the muscles, diminution of the threshold of motor nerves, etc., designated under the syndrome of tetany, result from hyperventilation. In 1924, Rosett,1in this country, and, almost simultaneously, Foerster,2in Germany, applied this method of investigation to the study of diseases of the central nervous system, especially to epilepsy. This proved to be a successful conception, as both authors were able to show that hyperventilation in epileptic patients may produce marked symptoms of motor and sensory excitation and even true epileptic seizures. Foerster stated that he observed epileptiform seizures in 55 per cent of his patients. Many subsequent investigations confirmed this interesting observation, and the results were at variance only in respect to the percentage of cases in which epileptic seizures followed forced voluntary hyperventilation. Other clinicians have been unable to