We do not need a prophet nor a doctor to tell us that sickness affects the mind. We know that dyspepsia, gout, or sluggish liver makes us peevish, stupid, jealous, suspicious, and despondent. We know that illness or weariness turns a sweet temper sour, makes a patient man impatient, a grateful man ungrateful. We know how trying are the caprices and whims of an invalid, and we commonly say of such, "he cannot help it: he is not himself to-day." But we do not know, as doctors know, how searching and how terrible are the effects of some diseases on the brain. Dr. Lydston, in _The Diseases of Society_, says: The old adage, _mens sana in corpore sano_, is too often forgotten. Especially is it ignored by the legislator and penologist. A normal psychic balance and a brain fed with blood that is insufficient in quantity or vicious in quality are physiologic incompatibles. The nearer we get to the marrow of criminality, the more closely it approximates pathology. 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. I quote again from Dr. Lydston: 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: