Berger has demonstrated the value of certain electrical signs of brain function which can be obtained from electrodes placed across the head—from forehead to occiput. The electro-encephalogram taken in this manner has been considered for the brain as analogous to the electrocardiogram for the heart. Abnormal brain potentials were found to accompany various pathologic processes which caused gross disturbances in the function of the entire cortex or of regions so located between the electrodes that they made their activity apparent in the composite picture thus obtained. Berger1reported a case in which slow waves could be picked up with one electrode directly over a tumor in the central part of the head, even though the electro-encephalogram from the forehead-occiput leads appeared normal. In a case of dementia paralytica in which there were periodic spasms of clonic twitching of the right arm and hand he2obtained large seizure waves