By far the largest part of the population of prisons is made up of the insane, feeble-minded, morons, defectives or victims of diseases that seriously influence conduct. This is especially shown by the increased percentage of the clearly defective that are repeaters, over those in prison for their first offense. There is no lack of statistics as to the various groups of defectives, but these figures cannot be reconciled. No two authorities agree as to percentages; the classifications are more or less uncertain; the dividing lines between the different groups are vague, one class easily fading into another. The investigations have largely been made by those not trained for the work, and above all the conclusions as to treatment are at variance, doubtful and necessarily not yet satisfactory. That the clearly insane and the plainly feeble-minded should not be punished would doubtless be admitted by all who speak in public or write for others to read. Many persons speaking in private, acting on juries and connected with the machinery of "justice" say that these should be punished like the rest. Still for a starting point, it may be assumed that most men would agree that these classes should be restrained rather than punished.
The chief difficulty is that between the most violently insane and the least emotional man are infinite numbers of gradations blending so closely that no one can mathematically or scientifically classify all the various individual units. While there are cases of insanity that can be clearly traced to injury or disease, the degree of sanity in most cases is still impossible to determine. Most insane people are sane on some things, generally on most things and are sane a part or most of the time. The periods of sanity and insanity can be distinguished only by conduct. How far any specific insanity may impair the brain and affect the inhibitions, is impossible to foretell.
When it comes to the defective, the problem is still more difficult. No two persons have the same degree of intelligence. Some are clearly lacking in mentality. Others are manifestly intelligent. The great mass range all along between these extremes. Various arbitrary rules have been laid down to aid in classifying different grades of defectives. Generally the feeble-minded can be sorted out. The defectives are supposed, if young, to be two years or more below the normal scholar in development; if older, three or more below. Their standing is fixed by asking certain test questions. Furthermore, a list of questions has been commonly used for an "intelligence test." These queries have nothing to do with the school work of the child, but are supposed to reveal only his native intelligence.