Mental powers that may be sufficient to enable a man to work and live in conformity with the law in one social position may be quite inadequate to enable him to support himself in another. There are men holding positions and discharging the duties required of them to the satisfaction of their employers, who would sink to a very low level if cast adrift. Any fixed standard of mental capacity is irrational, since it leaves out of account the conditions under which the person examined has to live. The question is: Is the person by reason of mental defect unable to bear the stress of life under the social conditions in which he is placed? Is he fit to take care of himself and abstain from offending against the laws? Whatever may be the view of lawyers on the matter, no business man expects the same conduct from a boy as from a man; nor will he trust a young man to the same extent as an old man. The younger man may possess more knowledge, but there is a difference between knowledge and experience, and a man may know right from wrong without having the experience of life that enables him to discount his passions and follow his knowledge. A person who is mentally defective, and who has the additional misfortune to be born into a family of poor people and brought up in a slum, if he transgress the law can only be dealt with as though he were as fully endowed as his neighbours. If he is not mentally unsound to such a degree as to justify his certification as insane, there is only the prison for him; with the prospect of hardships on liberation and imprisonment when he offends, till he is sufficiently mad, or his record and his condition combined are bad enough, to enable him to be placed under the treatment he ought to have received from the first. This is not necessarily the fault of those who administer the laws. The police are not justified in permitting offences to be committed; and whether the person who offends is sane or mentally defective it is their duty to arrest him. The medical men who may see him can only certify if they find him insane from their examination of him. Even if he is sent to an asylum the medical superintendent cannot detain him if his condition improves so far that he behaves sanely there; and out he goes to the old struggle that he is quite unfit to face, with no one to help him or to exercise authority over him when he has a wayward turn.