In a previous communication the subject of training was considered, and the deduction made that a trained act differed from an untrained act in respect of the composition of the excitation processes mediating the act (1). That is to say, though the formula H + L = T can be applied to both the trained and the untrained act, the trained act contains more L and less H than the untrained act. In other words, training adds L and diminishes H (1).