And when we remember the enormous number of crimes and offences which are not punished, for lack or inadequacy of evidence, and the frequency of trials which are based solely on circumstantial hints, it is easy to see the practical utility of the primary connection between criminal sociology and penal procedure.
The practical application of anthropometry to the identification of criminals, and to the question of recidivism, which was begun in Paris by M. Bertillon, and subsequently adopted by almost all the states of Europe and America, is too familiar to need description. It will be sufficient to recall the modifications of Bertillon's system by Anfosso, with the actual collection of anthropometric data, and their inclusion in the ordinary records of justice.
Thus the sphygmographic data on the circulation of the blood, which reveal the inner emotions, in spite of an outward appearance of calm or indifference, have already served to show that a person accused of theft was not guilty of it, but that he was on the contrary guilty of another theft, of which he had not been so much as suspected. On another occasion they established the innocence of a man condemned to death. We shall have more speaking and frequent illustrations when these inquiries have been placed regularly at the service of criminal justice.
The sphygmograph may also be useful in the diagnosis of simulated disease, after the example set M. Voisin in the case of a sham epileptic in Paris, ``whose sphygmographic lines have no resemblance to those of true epileptics before and after a fit, and only resemble those produced by normal persons after a violent gesticulation.''
As for the possible utilisation of hypnotism, we must be cautious before we draw any legal conclusions from it; but it cannot be questioned that this is a valuable source of scientific aid in the systematic collection of criminal evidence.
But, for the present, the most certain and profitable aids in the collection of evidence are those afforded by the organic and psychical characteristics of criminals. In my study on homicide I reckoned up many psychological and psycho-pathological symptoms which characterise the murderer, the homicidal madman, and the homicide through passion. And in my professional practice I have often found by experience that there is a great suggestive efficacy in these psychological symptoms in regard to the conduct of a criminal, before, during, and after a crime; and it is important to bring this knowledge scientifically before detectives and judges.
These data are not applicable to accused persons exclusively. When we remember the enormous importance of oral evidence in the chain of criminal proof, and the rough traditional empiricism of the criteria of credibility, which are daily applied in all trials to all kinds of witnesses, by men who regard them, like the prisoners, as an average abstract type--excluding only the definite cases of inability to give evidence, which are defined beforehand with as much method as the cases of irresponsibility-- the necessity of calling in the aid of scientific psychology and psycho-pathology is manifest.
For instance, not to dwell on the absurd violation of these traditional criteria of credibility, when police officers are admitted as witnesses (often the only witnesses) of resistance to authority or violence, wherein they are doubly interested parties, how often in our courts do we give a thought to the casual imaginations or credulity of children, women, weak-nerved or hysterical persons, and so on? Counsel for defence or prosecution who desired to know if any particular witness is or is not hysterical would bring a smile to the face of the judge, very learned, no doubt, in Roman law or legal precedents, but certainly ignorant in physiology, psychology, and psycho-pathology. Yet the tendency to slander in hysterical cases, which M. Ceneri urged so eloquently in a celebrated trial or the tendency to untruth in children, which M. Motet has ably illustrated, are but manifest and simple examples of this applicability of normal, criminal, and pathological psychology to the credibility of witnesses. And, under its influence, how much of the clear atmosphere of humanity will stimulate our courts of justice, which are still too much isolated from the world and from human life, where, nevertheless, prisoners and witnesses come, and too often come again, living phantoms whom the judges know not, and only see confusedly through the thick mist of legal maxims, and articles of the code, and criminal procedure.