Before recounting the general data of criminal anthropology, it is necessary to lay particular stress upon a remark which I made in the original edition of this work, but which our opponents have too frequently ignored. We must carefully discriminate between the technical value of anthropological data concerning the criminal man and their scientific function in criminal sociology. For the student of criminal anthropology, who builds up the natural history of the criminal, every characteristic has an anatomical, or a physiological, or a psychological value in itself, apart from the sociological conclusions which it may be possible to draw from it. The technical inquiry into these bio- psychical characteristics is the special work of this new science of criminal anthropology. Now these data, which are the conclusions of the anthropologist, are but starting-points for the criminal sociologist, from which he has to reach his legal and social conclusions. Criminal anthropology is to <p 6>criminal sociology, in its scientific function, what the biological sciences, in description and experimentation, are to clinical practice. In other words, the criminal sociologist is not in duty bound to conduct for himself the inquiries of criminal anthropology, just as the clinical operator is not bound to be a physiologist or an anatomist. No doubt the direct observation of criminals is a very serviceable study, even for the criminal sociologist; but the only duty of the latter is to base his legal and social inferences upon the positive data of criminal anthropology for the biological aspects of crime, and upon statistical data for the influences of physical and social environment, instead of contenting himself with mere abstract legal syllogisms. On the other hand it is clear that sundry questions which have a direct bearing upon criminal anthropology--as, for instance, in regard to some particular biological characteristic, or to its evolutionary significance--have no immediate obligation or value for criminal sociology, which employs only the fundamental and most indubitable data of criminal anthropology. So that it is but a clumsy way of propounding the question to ask, as it is too frequently asked: ``What connection can there be between the cephalic index, or the transverse measurement of a murderer's jaw, and his responsibility for the crime which he has committed?'' The scientific function of the anthropological data is a very different thing, and the only legitimate question which sociology can put to anthropology is this:--``Is the criminal, and in what respects is he, a normal <p 7>or an abnormal man? And if he is, or when he is abnormal, whence is the abnormality derived? Is it congenital or contracted, capable or incapable of rectification?''