'In sixty-one individuals electroencephalographic studies were obtained applying a new technique with a recording from the base of the brain. Thirty-six patients were suffering with headache, and there were twenty-five normal subjects. The basal brain activity found has been arbitrarily divided into three grades: I, low-voltage symmetric type; II, higher voltage, seven to fourteen waves per second, usually asymmetric, dominant in the left side; III, when the latter activity becomes intermingled with sharp waves or spikes. Both grades