The Use of Books.—No witness is allowed to quote from books, or to quote the opinion of other medical men on the subject, but he may refer to facts. Sir Henry Littlejohn, in his papers on Medical Jurisprudence,[2] gives some useful hints on this subject. It appears that a medical witness, in an unguarded moment, stated that his opinion was corroborated by a distinguished member of the medical profession not engaged on the trial. The judge informed the witness that it was most irregular to have other medical men present at the dissection than those mentioned in the warrant, and that, if the witness did not feel qualified for conducting such dissections, he had better resign the post of medical inspector.

In England, at the request of both parties, the medical and scientific witnesses may be excluded from the Court, but as a general rule they are allowed to be in Court, and hear the whole of the evidence of the case. In Scotland they are always excluded, although, by mutual consent, “experts” may remain to hear the general evidence on which they are to express their opinions, but when an expert is giving his opinion the others must leave the Court. In the latter country also, a medical witness who has been in Court cannot be examined on the facts of the case, but only on matters of opinion. A medical man is, however, sometimes allowed, on a special motion, to remain, although he is to be examined as to facts, and withdrawn when other witnesses are to be examined as to facts to which he is to speak. (See case of E. W. Pritchard, H.C. 1865; 5 Irv. 88.)

In giving evidence the witness should—(1) Speak loudly and distinctly. (2) Answer questions categorically—Yes or no. (3) Never use superlatives. (4) Give answers irrespective of results of trial. (5) Express no opinion as to guilt of prisoner; state facts only. (6) Avoid using technical terms. (7) Avoid long discussions, especially theoretical arguments.

When a quotation is made from a book by the examining counsel, the medical witness, before replying to a question based on it, should see that the quotation has been fairly and fully given, due regard being paid to the context. Neglect of this precaution may lead him into considerable difficulty.

A medical witness should remember that he is not retained for a party, but in the cause of justice. He must, therefore, be candid in his manner and simple in his language. Mr. Haslam remarks that, however dexterous a witness may show himself in fencing with the advocate, he should be aware that his evidence ought to impress the judge, and be convincing to the jury. Their belief must be the test by which his scientific opinion is to be established. That which may be deemed by the medical evidence clear and unequivocal, may not impress the judge, nor carry conviction to the jury.

The advice given by Sir W. Blizard may not be out of place here: “Be the plainest man in the world in a Court of Justice; never harbour a thought that if you do not appear positive, you must appear little and mean for ever after; many old practitioners have erred in this respect. Give your evidence in as concise, plain, and yet clear manner as possible; be intelligent, candid, open, and just, never aiming at appearing unnecessarily scientific. State all the sources by which you have gained your information. If you can, make your evidence a self-evident truth: thus, though the Court may at the time have too good or too mean an opinion of your judgment, yet they must deem you an honest man. Never, then, be dogmatic, or set yourself up for judge and jury; take no side whatever, be impartial, and you will be honest. In Courts of Judicature you will frequently hear the counsellors complain when a surgeon gives his opinion with any of the least kind of doubt, that he does not speak clearly; but if he is loud and positive, if he is technical and dogmatic, then he is allowed to be clear and right. I am sorry to have to observe that this is too frequently the case.”

Liability of Medical Men to reveal Professional Secrets.—The question has arisen how far a medical man is bound to reveal the secrets confided to him in his professional capacity as medical attendant. This question was raised by Mr. Cæsar Hawkins in the trial of the Duchess of Kingston (11 Harg. St. Tri. 243), before the House of Peers, and decided by Lord Mansfield thus: “Mr. Hawkins will understand that it is your (the other Peers) judgment and opinion that a surgeon has no privilege, where it is a material question in a civil or criminal course to know whether parties were married or whether a child was born, to say that his introduction to the parties was in the course of his profession, and in that way he came to the knowledge of it. I take it for granted, that if Mr. Hawkins understands that, it is a satisfaction to him and a clear justification to all the world. If a surgeon was voluntarily to reveal these secrets, to be sure he would be guilty of a breach of honour, and of great indiscretion; but, to give that information in a Court of Justice, which, by the law of the land, he is bound to do, will never be imputed to him as any indiscretion whatever.” However objectionable it may be to the medical witness, and be considered by him a breach of professional confidence, to reveal in a Court of Law secrets known but to himself and patient, and regarded as sacred, he has no privilege but to reveal them if demanded as evidence, unless the evidence be such as might incriminate himself. This is not the ruling in most Continental countries, where the medical man claims the same privileges of secrecy as the priest in confessional.

3. EXPERIMENTAL

Under this head will be treated Identity and the examination of the Living and the Dead, Real and Apparent Death, Cause of Death, Exhumations, and Autopsies.

Identity