knows that arrests of brain development occasion imbecility, that blows on the head abolish memory or consciousness, and that brain-stimulants and poisons change the quality of our ideas. The anatomists, physiologists, and pathologists have only shown this generally admitted fact of a dependence to be detailed and minute. What the laboratories and hospitals have lately been teaching us is not only that thought in general is one of the brain's functions, but that the various special forms of thinking are functions of special portions of the brain. When we are thinking of things seen, it is our occipital convolutions that are active; when of things heard, it is a certain portion of our temporal lobes; when of things to be spoken, it is one of our frontal convolutions. Professor Flechsig of Leipzig (who perhaps more than any one may claim to have made the subject his own) considers that in other special convolutions those processes of association go on, which permit
