A very small proportion of prisoners are persons of unsound mind, and in most cases the mental unsoundness is the result of their own misconduct. In Scotland there is no difficulty in freeing insane persons from prison. By section 6 of the Criminal and Dangerous Lunatics (Scotland) Amendment Act, 1871, it is provided that "When in relation to any person confined in a local prison in terms of the Prisons (Scotland) Administration Act, 1860, it is certified on soul and conscience by two medical persons that they have visited and examined such prisoner, and that in their opinion he is insane, it shall be lawful for the sheriff, on summary application at the instance of the administrators of such Prison, by a warrant under his hand, to order such prisoner to be removed to a lunatic asylum." The matter practically rests with the prison surgeon, for the prison commissioners on his report never raise any objection to the transfer of a convicted prisoner who is found to be insane. Yet the same persons return again and yet again. The warrant for detention in an asylum expires with the period of the sentence of imprisonment, and the asylum authorities must obtain new certificates before they can continue to keep the patient. When the degree and kind of mental unsoundness is very marked there is no difficulty in getting the necessary documents; but when the patient has been benefited to the extent of being able to behave and speak no worse than many of his fellow-criminals, it is different. He is sent for examination to a man who is not acquainted with him. The doctor has to state facts observed by himself as a ground for certification; quite properly he is not permitted to ensure the detention of anybody on evidence that is second-hand. The patient is quiet and on his guard, and his examiner can make nothing of him. Accordingly he goes back to his haunts and his vices, impatient of restraint, and is soon in the hands of the police again. Clearly there is need of some modification in the law or its administration to permit of such persons being dealt with. Insane offenders may be divided into two classes: those whose wrongdoing is the result of their insanity; and those who have been sound enough to begin with, but who have become insane, just as they have contracted physical diseases, as a result of vicious indulgence and its treatment. Of the first-named class there may be one in about a thousand admissions. The crimes charged are of all kinds and degrees of gravity, as the following examples will show:--