Insanity may be of congenital origin or slowly developed from early childhood, but usually it indicates a change caused by disease, so that the person alleged to be insane must, as a rule, be compared with himself at some previous time, and not with some ideal standard of mental health which does not exist. Indeed, if we could measure nicely no two of us could be fairly held to precisely the same degree of accountability. The knowledge of right and wrong is not a fair criterion, as many insane men possess that knowledge well enough in the abstract. The ability to distinguish right from wrong in the particular act is possessed by some insane persons whose will and power of self-control have become so limited by disease that they cannot avoid what they know to be crime. Delusion overpowering the mind is sufficient evidence of irresponsibility, but all delusions are by no means so powerful that they cannot be resisted, and many must be classed as simply false beliefs or mistaken views which could be, and should be, controlled. In case, therefore, of alleged delusions not manifestly insane further evidence of insanity is required, and the way in which a man believes or does anything may be more of an indication as to the soundness or unsoundness of his mind than what he believes or does. A crime committed under the influence of maniacal delirium, acute delirious mania, epileptic furor, uncontrollable impulse, alcoholic insanity, or hysterical mental disease will usually explain itself, while a demented insane person is so characteristic an object that his crime cannot well be mistaken for that of a responsible agent. The different conditions of mind grouped under the general terms moral insanity, affective insanity, and impulsive insanity are still the bugbear of jurists, and there is a wide difference of opinion as to the degree of accountability for actions performed under the influence of moral perversion with only slight intellectual impairment; but the degree to which the individual deviates from the path of the law may depend more upon his training and surroundings than upon his disease—points which must always be considered in establishing a definition of insanity in obscure cases. Of two persons whose circumstances in life, in connection with a certain amount of disease, have produced as nearly as possible identical morbid mental states, it now and then happens that the necessary surroundings of the one steady and support him, while the associations and conditions of life throw the other still more off his balance. The one is able to sustain the ordinary relations with the world, the other not.