The examination of a criminal or person of criminal tendencies should, if possible, be preceded by a careful investigation of his antecedents. Questions put to relatives and friends often bring to light facts relating to his past life, and give an idea of the surroundings in which he has grown up and the illnesses suffered by him during childhood (meningitis, typhus, convulsions, hemicrania, giddiness, _pavor nocturnus_, trauma). The prevalence of disease in the family (parents, grandparents, uncles, cousins, etc.) should be elicited and note taken not only of nervous maladies, but of arthritic, tuberculous, pellagrous, and inebriate forms, including a tendency to morphiomania. Even goitre should not escape notice, since it may indicate cretinism or any other form of degeneration. The existence of criminality in the family is of still greater importance, but it is extremely difficult to obtain any information on this head, either from the patient himself or his relatives. A certain amount of strategy must be used in eliciting facts of this kind, by suddenly asking, for instance, whether a certain individual of the same name, already deceased or confined in such-and-such an asylum or prison, is any relation of the patient. Next should be ascertained whether he is single or married, and in the latter case, whether his wife is still living; also what profession or professions he has exercised. In this connection it should be observed that although criminals are generally successful in everything they undertake, they are incapable of remaining constant to one thing for any length of time. Many persons, cooks, tavern-keepers, confectioners, etc., exercise callings that have a deleterious effect on the nervous centres and encourage an abuse of alcohol; others like bakers, have night work, which is equally harmful. Professions which bring poor men, servants, secretaries, cashiers, etc., into close contact with wealth, are sometimes the cause of dishonesty in those who in the absence of special temptations, would have remained upright; others provide criminaloids with opportunities or instruments for accomplishing some crime, as in the case of locksmiths, blacksmiths, soldiers, doctors, lawyers, etc. The time of the year and other circumstances under which the crime takes place should be elicited, and it should be borne in mind that the vintage season in countries of Southern Europe and extremes of heat and cold are favourable to seizures of an epileptic nature. When the subject under examination is a recidivist, care should be taken to ascertain at what age and under what circumstances the initial offence was committed. Precocity in crime is a characteristic of born criminals, and puberty and senility have their peculiar offences, as have the extremes of poverty and wealth.