The more material powers of the mind of the criminal frequently elude the examiner and tools which can be too "systematic." This, because the examiner faces cards which the examined instinctively employ every means at their command to euchre. Also, if his limited scope of criminological vision causes him to over-emphasize present emphasis, and to bolt the way-backward trail of his subject, the examiner will remain as half blind to the basic reasons for a given criminal. Cardinal causes for the criminal commonly hark back to remote ancestors. And so, for example, one unacquainted with the early history of the Sicilian people, the events of which changed so many of that people from trustful, mutually helpful sons of the soil, into dagger-thrusting brigands, lunging for the hearts of their blood brothers, has no call to classify the alien Sicilian-Italian who makes America his base of operations. That is essentially so, because the period from bib to puberty is the most impressionable after-birth period, during which a lad will tend to take on much that will aggravate congenital predisposition; predisposition the more fateful for the reason that it lurks in the unconscious, and there constantly presses upon its victim for expression. Hence, psycho-physical research that does not cover the whole field of motive and motion, is comparatively valueless. By the same token, the investigator who is casehardened with technical lore, will be very likely to miscall the turn, especially on the alien and near-alien criminal. Above all else, the psychiatrist must measure the criminal with an absolutely open mind, attuned alike to individual and racial determination; attuned, also, to his own definitions, such as that psychic contagion is "transfer of nervous disease by imitation"; and attuned to the fact that the mode of operating employed with Awasco, the sunny-hearted, comparatively ingenuous "Wop," anxious to help, won't do at all with Hungarian Zynthner the sullen, who is evasive, suspicious, and resentful alike of authority and the personal touch, because he still bristles over hurts visited upon him and his by thick-lipped Hapsburgs. Mental searching of the latter class of criminals usually yields next to nothing that is specifically of capital importance. For want of the master-key to the situation, the operator leaves the tested laughing up their sleeves over having fundamentally over-reached the tester. Needless to add, the master-key is mostly shaped of the metal of foreign soil, and unlocks the far-removed circumstance. First off, the really expert examiner will seek to win the undivided attention, full confidence, and voluntary coöperation of his man, who is to be led only by judicious degrees to the conviction that the questioner is not a mere cog of a "scientific" machine, the purpose of which is to bare the subject's soul, regardless of his feelings in the matter.