No greater mistake could be made, for a prisoner's behaviour has nothing do with to his guilt or innocence. On the whole, fear or distress are far more likely to indicate innocence than they are to denote guilt. This I believe to hold good of all prisoners, not only of those charged with the capital offence. I have failed to observe in prisoners who were undoubtedly guilty the furtive look that is supposed to be peculiar to guilt. I have watched closely and have spoken confidentially to many hundreds, but their eyes met mine as naturally as those of a child. I have been compelled to the conclusion that not only is a bold bearing consistent with the deepest guilt, but also that a natural bearing and a childlike trustfulness are by no means to be taken as signs of innocence. Of the behaviour of innocent people when charged with crime, fortunately, we do not get many opportunities of observation; still, I have seen some, and can bear testimony that they were a great deal more confused, excited, and unreliable than prisoners who were undeniably guilty. Such prisoners often contradict themselves, and sometimes depart from the truth when attempting to defend themselves. It is palpable to everyone that they feel their position, and fear the consequences. I have seen such astounding coolness and presence of mind, coupled with apparent candour and sincerity, among guilty prisoners that when I know of a prisoner exhibiting these qualities I almost instinctively suspect him. An innocent man, in his anxiety, may prevaricate through fear and confusion; but the veritably guilty man is careful in these matters, though he may be sometimes a little too clever.
The psychology of prisoners has, then, for years been a favourite study with me, and a very interesting study I have found it. In my endeavours to discover the state of mind that existed and caused certain prisoners to commit serious crimes, I have sometimes discovered, almost hidden in the dark recesses of the mind, some little shadow of some small thing that to me seemed quite absurd, but which to the prisoner loomed so large, so real, and so important, that he regarded it as a sufficient justification for his deed. To myself the crime and the something in the prisoner's mind appeared to have no possible connection, yet unmistakably, if the prisoners were to be believed, they were cause and effect. Now, from this kind of mania--for such it undoubtedly is--small and ridiculous as it seems--and I have met it too often not to be certain as to its existence--a double question is presented: What is the cause of that little something in the prisoner's mind? and why has it caused the prisoner to commit a certain action? I have never been able to get any light upon these questions, but have had to content myself with the knowledge that the mental equipment of that class of criminals is altogether different to that of ordinary individuals. I am not here speaking of a defined mania that dominates the life, stirs the passions, and leads directly to the perpetration of a crime--cause and effect in such a case are obvious, though, of course, the cause of the cause is still obscure--but I am speaking of silly little somethings that float about in certain minds, that refuse to be ejected, that entail much misery and suffering, and finally crime. Possibly this state of mind may be the outcome of indigestion, even as an extra severe sentence upon a prisoner may be the outcome of indigestion in a judge: for it is quite possible to suppose a case in which judge and prisoner suffered from a like cause; but the one has committed a crime because of it, and the other inflicts unmerited punishment because of it. Two things are very clear to me: first, that our judges and magistrates ought to be in the very best of health when performing their duties; secondly, that pathological causes enter very largely into the perpetration of crime. Ill-health may make a judge irritable and severe, and so distort his judgment, and excuses are made for him; for it is whispered he is a martyr to gout, indigestion, or some equally trying malady. If so, he certainly ought not to be a judge, for health and temper are absolutely necessary for one who has to administer justice and act as the arbiter of other people's fate. But this excuse is not made for prisoners. Yet in hundreds of cases it might honestly be made; for while they may not have been influenced by gout or indigestion, they have been influenced by pathological causes, and the two things are equal.