842 THE AMERICAN JOURNAL OF SOCIOLOGY
to be sufficient definite knowledge of living civilized man, to become a science, it can only be gained by the study of large numbers of persons.
Conclusions depending on small numbers are useful and instructive, but if they are to carry weight, they must be based upon numerous individuals of all classes.
But the psycho-physical study is not all the work. Of no less importance are the sociological investigations involved, including the gathering of anthropological and medical data. In new work the field is always too large, and therefore it would be imperative at first to study in those parts only which will bring results most useful to society.
INVESTIGATION OF CRIMINAL AND DEFECTIVE CLASSES.
A special and very practical feature of a psycho-physical laboratory would be the study of the criminal and defective classes. As in machinery we must first repair the little wheels out of gear, so in society we must first study the criminal, crank, insane, inebriate, or pauper who can seriously injure both indi- vidual and community. The community is most directly con- cerned, for it pays out millions to catch, try, and care for criminals, but almost nothing to study the causes that lead to crime. Thus in 1890 the expenses of all our penal institutions were more than twelve million dollars. This does not include the cost of criminal or police courts, of the property stolen, or the untold injury to society. A worthless criminal or crank kills a prominent citizen ; the injury from such action is often beyond calculation.
CHILDREN SHOULD BE STUDIED FIRST.
However valuable the results of the investigation of man may be, they will always have an additional value when coming from the study of children. For whatever may be found of a detri- mental character in both mind and body will always have a much better chance of correction in the child than in the adult.
We cannot expect to lessen crime and dangerous forms of abnormality unless we study the causes; this is the first requisite in all rational procedure ; and these causes should be sought out
