Notwithstanding the many ingenious hypotheses advanced to explain epilepsy, it still must be assumed that it is a disease of unexplained etiology. In the present state of information, it might be best regarded as the result of an increased irritability of the cerebral cortex, occurring as an expression of organ inferiority, with the seizures as responses of this cortex to stimuli of exogenous or endogenous origin. The fact that most patients at first have nocturnal fits, then nocturnal and diurnal ones, and that there is a tendency toward an increase in the number of seizures, might best be explained on the principle that every nervous activity is enhanced by each preceding one; in other words, each epileptic seizure predisposes to the following one. While it takes considerable time for the highly irritable cortex to respond to the stimuli, when once it has responded, it is much easier for the following