The patient was a child of 7 years, of good family history, both direct and collateral. No other members of the family suffered from epilepsy, and there was no evidence of syphilis. Somewhat slow in development, she began to walk and speak in her fourth year. About this time she would fall down with loss of consciousness lasting from five to six minutes. Bromide diminished these attacks, but afterwards marked convulsions developed, without aura or cry, with frothing at the mouth, incontinence of urine, marked prostration, and headache. Further symptoms supervened. On examination the patient was found to be well developed and nourished. Each three or four months she suffers from the convulsive attacks previously described. Percussion of the head causes the following phenomena:—A light blow on the scalp or face without warning to the child causes either an immediate fall or sudden and very marked trembling, and movements in the upper limbs are noticed. These bear no relation to the strength of the blow, and any hurt to the body produces no effect. Methodical percussion over the motor areas does not produce any isolated contraction. There is no difference on the two sides of the cranium. Excitement increases the effects. Anæsthesia of a skin area by chloride of ethyl produces no alteration. Electrical stimulation does not influence the condition. After the fall the child arose crying and agitated, the walk was uncertain and hesitating, the arms being used to balance, and she walked zigzag, as if the power of directing herself were lost—almost like a cerebellar gait.