That is to say that the sound mind depends largely on the sound body; that a brain fed with diseased blood, or with too little blood, cannot work healthily and well; and that the more we know of crime the closer do we find its relation to disease.
Despite the scant and conflicting testimony of cerebrologists with reference to the brain defects of criminals, there is so much clinical evidence of the aberration of morals and conduct from brain disease or injury that we are justified in believing that brain defects of some kind affecting the mental and moral faculties is the _fons origo_ of criminality. This defect, as already seen, may be congenital or acquired, and may consist of a lack of development due to vicious environment and faulty education, mental and physical.
The fountain from which crime arises, says this authority, is some form of disease, or defect of the brain. And such disease or defect may be inherited, or may be caused by bad environment: by improper teaching, food, and exercise. To feel the full force of this statement we must bear in mind that "children are not born with intellect and conscience, but only with capacities for their development."
Therefore, if the capacities for intellect and morals are _not_ developed, we cannot expect to find the intellect and morals.
In other words, we have no right to hope nor to expect that the neglected child will grow up into the good and clever man.
Neither is it reasonable to hope for a cure by pumping moral lessons into a brain in which no moral sense has been developed.
That epilepsy has a bad effect on morals, and that epileptics are often untruthful, treacherous, and dangerous is as well known as that epilepsy is a form of degeneracy, and is often caused by improper feeding and neglect in childhood.
Hysteria also affects the moral nerves of the brain. Dr. Lydston says:
Hysterical women often bring accusations of crime against others. The victim is generally a man, and the alleged crime, assault. Physicians recognise this as one of the dangers to be guarded against in their work. Hysterical women in the primary stage of anaesthesia, sometimes imagine themselves the victims of assault. In one well-known case the woman accused a dentist of assault while he was administering nitrous oxide to her. Her husband was in the room during the imaginary assault.