Monozigotic twin-girls 6 8/12 years old, one right-handed girl and the other left-handed, present petit mal seizures, appeared contemporaneusly when the twin-girls were 5 years old. The Eleccal tracing of petit mal with these troencephalogram shows a typicaracteristics: in the left hemisphere of the right-handed girl and in the right of the left-handed girl there is a preponderance of attivity.
One sister of the twis-girls, 8 years old, has a tracing with epilectical activity spike-wawe 3 per second of high voltage; she never had clinical seizures.
The mother's, 34 years old, present a tracing on activation, with teta activity 7 per second of low voltage.
The tracing of the father, 33 years old, is negative.
The tracing of the maternal-grand mother, 67 years old, present on activation, a light dysrithmia in the Pa O. right seat.
The AA take from these dates some considerations about the question of the heredity in the Epilepsy and conclude on the base of their researches that they could favour the conception that existe in the epilepsy a functional miopragie of the brain, on hereditary base. These miopragies are, probably, connected with one functional differentiation deficiency of determined structures of the central-nervous-system.