682 THE AMERICAN JOURNAL OF SOCIOLOGY
and in investigating the classes which are not criminal, but from which the criminals come. At various points throughout there have been suggestions of the way in which the psychological tests have suggested social factors or have supplemented the data secured through them. The ascertainment of a condition, such as defective hearing or taste, has stimulated inquiry which has revealed methods of living, habits, disease, etc., and almost all the tests have suggested the need of a more complete investi- gation. Association of ideas, the respiration curves, reading and hearing tests, and those for memory have thrown valuable light upon mental faculties and their operation ; respiration tests sensibility to pain, precision and reaction time tests have been of great suggestive value in the emotional nature, which the criminal has so well developed. Thus psychology and sociology are indispensable in scientific research in criminality.
Psychology makes possible a quantitative sociology. This is a step in advance of statistical sociology. The psychological method applied to sociological data renders them more accurate, more definite. Two things a.e needed in a study of criminal sociology : such a presentation of facts as shall make possible a more rational, helpful attitude upon the part of the non-criminal class ; legislation which shall be compelled to recognize these facts, and not revert to the precedents of the Middle Ages for its initiative. The needs are such as to press into the service of social investigation any science which renders it more trust- worthy and liberal, and which relieves it from the charge of mere theorizing.
Frances A. Kellor.
The University of Chicago.
