Up to the present time the experimental movement in psychology has been directed chiefly to the study of methods by which mental phenomena may be subjected to exact investigation, and by which they may receive for purposes of comparison some kind of quantitative expression. So far as these methods have been perfected they have been directed mainly to the investigation of general psychological laws, and of the relation of psychological to physiological processes. Comparatively little has been done in the way of application of these methods to elucidate practical questions; little attention has been paid to individual psychology and to the exact nature of the differences which distinguish the various types of normal and abnormal mind. The more theoretical work of experimental psychologists has naturally a great interest for students of insanity, and must affect their conceptions of abnormal mind, but the special question which I intend to consider is of a more direct and practical kind, viz., the possibility of using the methods of experimental psychology to help directly in the study of the problems of insanity.