But the roots of criminality are not only deeper than professionalism, they are deeper also than any merely acquired disease. I have frequently had occasion to note the remarkable resemblances between criminals and idiots. There is the same tendency to anatomical abnormalities of the muscles, arteries, bones, etc.; in both the muscular system is weak; there is the same tendency also to small and weak hearts, with valvular defects. There is, again, the same sensory obtuseness, with the same exception in the case of sight, which is remarkably good, with rarity, it seems, of colour-blindness. Criminality, like idiocy, tends to run in the line of the eldest sons, and in both the hereditary influences are frequently bad. Cranial asymmetry is common in idiots as well as among criminals; and while meningitis is a common cause of idiocy, such evidence as we possess shows that it is also common in criminals. Tubercular disease is again common in both. Epilepsy, to which so much importance has of late been attached in connection with criminality, is notoriously common among idiots, being found among nearly 25 per cent.[89] The relations of criminality to idiocy have not yet been sufficiently studied. The criminal is, however, by no means an idiot. He is not even a merely weak-minded person. The idiot and the feeble-minded, as we know them in asylums, rarely have any criminal or dangerous instincts. Another term is frequently used to denote vicious or criminal instincts in a person who is, mentally, little if at all defective; he is said to be “morally insane.” The term “moral insanity” was originated nearly half a century ago by an Englishman, Dr. Prichard, who in his _Treatise on Insanity_ declared that insanity exists sometimes with an apparently unimpaired state of the intellectual faculties; and the conception has been developed by Krafft-Ebing, Maudsley, and many others. The term itself is an unfortunate one; the condition described by no means falls in easily as a subdivision of insanity, and it is moreover frequently of a congenital character. There is now a very general tendency to drop the expression “moral insanity,” and to speak instead of “moral imbecility.”