The reliability of prisoners' statements--Deceit or misunderstanding?--Frankness and knowledge required on the part of the investigator--The prisoner's statement should form the basis of enquiry--Information and help obtained from former friends--The diffusion of knowledge so obtained--The prevention of crime and the accumulation of knowledge. Any study of the criminal based on observations made when he is in prison must of necessity be partial and misleading. It is like writing a Natural History from a study of caged birds. Parts will be right, but the whole will be wrong. Advantage might be taken of his presence there to find out something of the antecedents of the prisoner. The opinions of experts may be of value with regard to him, but they are not nearly so useful as his own opinions on how he comes to be in prison, nor are they more reliable. Prisoners are no more truthful than other people, but they are not generally purposeless liars. When a man is in trouble and is called on to give an account of himself he makes the best of his case; but people who have never been in prison have been known to make no disclaimer when praised for qualities they do not possess, preferring to let time correct any false impression that may be to their advantage. It is not reasonable to expect any higher standard of behaviour from a prisoner than we look for from others. Much of what is harshly called lying on the part of prisoners is due to misapprehension on the part of their questioners. Most of them do not waste lies. If the truth will serve, it is easier to tell it, to put the matter at its lowest; but they are frequently worried with questions they do not understand, put by persons whom they distrust, with the result that they leave an impression of stupidity and untrustworthiness that is not deserved. I remember a gentleman who considered himself a very acute observer, informing me with regard to a certain prisoner whom he had been questioning, that the man was weak-minded. I had very good reason for holding another opinion, but wishing to find out how the visitor had arrived at this conclusion, I interviewed the prisoner, and after some talk approached the subject of his recent examination. A smile overspread his face as he explained that he had been asked all sorts of questions by the stranger and had not been allowed to answer in his own way, so he got tired and let the other have it as he wished. His opinion of his examiner I obtained as a personal favour, for as he put it, "It's no for the like o' me to say onything aboot the like o' him--at least no here." I cannot print his words, all of them. He said, "He's a ---- of a flat." Each had a poor opinion of the other, and how far each was right others may judge. The incident suggests several reflections.