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. <p 169> 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. Apart from these examples, which prove the importance of what M. Sarraute justly called ``judicial applications of criminal sociology,'' the fundamental reform needed in the scientific preparation of criminal <p 170>evidence is the creation of magisterial experts in every court of preliminary inquiry. In a question of forgery, poisoning, or abortion, the judge has recourse to experts in handwriting, chemistry, or obstetrics; but beyond these technical, special, and less frequent cases, in every criminal trial the basis of inquiry is or ought to be formed by the data of criminal biology, psychology, and psycho-pathology. So that, over and above the knowledge of these sciences which is necessary to judges, magistrates, and police officers, it is most important that an expert, or several experts in criminal anthropology should be attached to every court of criminal inquiry.