Gall thrust aside for ever the credulous fancies of the physiognomists; and he has been described, not altogether without reason, as the founder of the modern science of criminal anthropology. He was certainly its most brilliant pioneer. Lavater believed in the homogeneity of the human organism, but he was not a man of science, and he had been content to study the surface of the body; Gall, with true scientific instinct, tried to get to the root of the matter; following the great English anatomist, Willis, who had made some attempt at cerebral localisation, he studied the brain, sought to differentiate the functions of its various parts, and the effects of its varying development on the skull. For Gall the varying development of the brain was the cause of the divergent mental and moral qualities of the individual; he was firmly convinced that all the facts of psychical life are rooted in the physical organisation; he wished to write the natural history of every primitive moral and intellectual force, in health as well as in disease. To the best of his ability he carried out this programme in detail, by an unceasing study of all the varieties of the brain and of the living head that he could find; he pursued his studies throughout Europe, in lunatic asylums and in prisons, as well as among the ordinary population, and he foresaw the extent of the applications of the science he was opening up to medicine and to law, to morality and to education. While his work extended far beyond the borders of what we should now call criminal anthropology,[13] he devoted much attention to the problems of the criminal organisation, and even to its varieties, many of his observations according well with the results of recent investigation. More than this, following Galen and Diderot (who had written, fifty years earlier, “The evil-doer is one whom we must destroy, not punish”), he clearly advocated a method of dealing with the criminal which is now widely regarded as the only right and reasonable method. “There can be no question,” he said, “of culpability or of justice in the severe sense; the question is of the necessity of society preventing crime. The measure of culpability and the measure of punishment cannot be determined by a study of the illegal act, but only by a study of the individual committing it.” In his great work, _Les Fonctions du Cerveau_ (1822), Gall has summed up his conclusions.