Until comparatively recent years the fact that what was called psychology did not even pretend to be of any practical value in affairs was tolerated by its professors and regarded as more or less in the nature of things. The science, therefore, outside a small class of specialists was in very dismal reputation. It had come to comprise two divergent schools, one which busied itself with the apparatus of the experimental physiologist and frankly studied the physiology of the nervous system, the other {70} which occupied itself with the faded abstractions of logic and metaphysics, while both agreed in ignoring the study of the mind. This comparative sterility may in a broad way be traced back to the one fundamental defect from which the science suffered—the absence of an objective standard by which the value of mental observations could be estimated. Failing such a standard, any given mental phenomenon might be as much a product of the observing mind as of the mind observed, or the varying degrees in which both of these factors contributed might be inextricably mixed. Of late years the much-needed objective standard has been sought and to some extent found in two directions. What I have called “human” psychology has found it in the study of diseases of the mind. In states of disease mental processes and mechanisms which had eluded observation in the normal appear in an exaggerated form which renders recognition less difficult. The enlightenment coming from the understanding of such pathological material has made it possible to argue back to the less obtrusive or more effectively concealed phenomena of the normal and more or less to exclude the fallacies of the observing mind, and, at any rate in part, to dissipate the obscurity which for so long had successfully hidden the actual mental phenomena themselves.