On being called, the medical witness enters the witness-box and takes the oath. This is very generally done by uplifting the right hand and repeating the oath (Scottish form), or by kissing the Bible, or by making a solemn affirmation.

1. He may be called to give ordinary evidence as a common witness. Thus he may be asked to detail the facts of an accident which he has observed, and of the inferences he has deduced. This evidence is what any lay observer might be asked.

2. Expert Witness.—On the other hand, he may be examined on matters of a technical or professional character. The medical man then gives evidence of a skilled or expert nature. He may be asked his opinion on certain facts narrated—e.g., if a certain wound would be immediately fatal. Again, he may be asked whether he concurs with opinions held by other medical authorities.

In important cases specialists are often called to give evidence of a skilled nature. Thus the hospital surgeon, the nerve specialist, or the mental consultant may be served with a subpoena to appear at court on a certain date to give evidence. The evidence of such skilled observers will, it is supposed, carry greater weight with the jury than would the evidence of an ordinary practitioner.

Skilled witnesses may hear the evidence of ordinary witnesses in regard to the case in which they are to give evidence, and it is, indeed, better that they should understand the case thoroughly, but they are not usually allowed to hear the evidence of other expert witnesses.

In civil cases the medical witness should, previous to the trial, make an agreement with the solicitor who has called him with reference to the fee he is to receive. Before consenting to appear as a witness the practitioner should insist on having all the facts of the case put before him in writing. In this way only can he decide as to whether in his opinion the plaintiff or defendant is right as regards the medical evidence. If summoned by the side on which he thinks the medical testimony is correct, then it is his duty to consent to appear. If, however, he is of opinion that the medical evidence is clearly and correctly on the opposite side, then he ought to refuse to appear and give evidence; and, indeed, the lawyer would not desire his presence in the witness-box unless he could uphold the case.

Whether an expert witness who has no personal knowledge of the facts is bound to attend on a subpoena is a moot point. It would be safer for him to do so, and to explain to the judge before taking the oath that his memory has not been sufficiently 'refreshed.' The solicitor, if he desires his evidence, will probably see that the fee is forthcoming.

A witness may be subjected to three examinations: first, by the party on whose side he is engaged, which is called the 'examination in chief,' and in which he affords the basis for the next examination or 'cross-examination' by the opposite side. The third is the 're-examination' by his own side. In the first he merely gives a clear statement of facts or of his opinions. In the next his testimony is subjected to rigid examination in order to weaken his previous statements. In the third he is allowed to clear up any discrepancies in the cross-examination, but he must not introduce any new matter which would render him liable to another cross-examination.

The medical witness should answer questions put to him as clearly and as concisely as possible. He should make his statements in plain and simple language, avoiding as much as possible technical terms and figurative expressions, and should not quote authorities in support of his opinions.

An expert witness when giving evidence may refer to notes for the purpose of refreshing his memory, but only if the notes were taken by him at the time when the observations were made, or as soon after as practicable.

There are various courts in which a medical witness may be called on to give evidence:

1. The Coroner's Court.—When a coroner is informed that the dead body of a person is lying within his jurisdiction, and that there is reasonable cause to suspect that such person died either a violent or unnatural death, or died a sudden death of which the cause is unknown, he must summon a jury of not less than twelve men to investigate the matter—in other words, hold an inquest—and if the deceased had received medical treatment, the coroner may summon the medical attendant to give evidence. By the Coroners (Emergency Provisions) Act of 1917, the number of the jury has been cut down to a minimum of seven and a maximum of eleven men. By the Juries Act of 1918, the coroner has the power of holding a court without a jury if, in his discretion, it appears to be unnecessary. In charges of murder, manslaughter, deaths of prisoners in prison, inmates of asylums or inebriates' homes, or of infants in nursing homes, he must summon a jury. The coroner may be satisfied with the evidence as to the cause of a person's death, and may dispense with an inquest and grant a burial certificate.

Cases are notified to the coroner by the police, parish officer, any medical practitioner, registrar of deaths, or by any private individual.

Witnesses, having been cited to appear, are examined on oath by the coroner, who must, in criminal cases at least, take down the evidence in writing. This is then read over to each witness, who signs it, and this forms his deposition. At the end of each case the coroner sums up, and the jury return their verdict or inquisition, either unanimously or by a majority.

If this charges any person with murder or manslaughter, he is committed by the coroner to prison to await trial, or, if not present, the coroner may issue a warrant for his arrest.

A chemical analysis of the contents of the stomach, etc., in suspected cases of poisoning is usually done by a special analyst named by the coroner. If any witness disobeys the summons to attend the inquest, he renders himself liable to a fine not exceeding £2 2s., but in addition the coroner may commit him to prison for contempt of court. In criminal cases the witnesses are bound over to appear at the assizes to give evidence there. The coroner may give an order for the exhumation of a body if he thinks the evidence warrants a post-mortem examination.

Coroners' inquests are held in all cases of sudden or violent death, where the cause of death is not clear; in cases of assault, where death has taken place immediately or some time afterwards; in cases of homicide or suicide; where the medical attendant refuses to give a certificate of death; where the attendants on the deceased have been culpably negligent; or in certain cases of uncertified deaths.

The medical witness should be very careful in giving evidence before a coroner. Even though the inquest be held in a coach-house or barn, yet it has to be remembered it is a court of law. If the case goes on for trial before a superior court, your deposition made to the coroner forms the basis of your examination. Any misstatements or discrepancies in your evidence will be carefully inquired into, and you will make a bad impression on judge and jury if you modify, retract, or explain away your evidence as given to the coroner. You had your opportunity of making any amendments on your evidence when the coroner read over to you your deposition before you signed it as true.

By the Licensing Act of 1902, an inquest may not be held in any premises licensed for the sale of intoxicating liquor if other suitable premises have been provided.

The duties of the coroner are based partly on Common Law, and are also defined by statute, principally by the Coroners Act of 1887 (50 and 51 Vict. c. 71). They have been modified, however, by subsequent Acts—e.g., the Act of 1892, the Coroners (Emergency Provisions) Act, 1917, and the Juries Act of 1918.

The fee payable to a medical witness for giving evidence at an inquest is one guinea, with an extra guinea for making a post-mortem examination and report (in the metropolitan area these fees are doubled). The coroner must sign the order authorizing the payment, and should an inquest be adjourned to a later day, no further fee is payable. If the deceased died in a hospital, infirmary, or lunatic asylum, the medical witness is not paid any fee. Should a medical witness neglect to make the post-mortem examination after receiving the order to do so, he is liable to a fine of £5.

In Scotland the Procurator Fiscal fulfils many of the duties of the coroner, but he cannot hold a public inquiry. He interrogates the witnesses privately, and these questions with the answers form the precognition. More serious cases are dealt with by the Sheriff of each county, and capital charges must be dealt with by the High Court of Justiciary. In Scotland the verdicts of the jury may be 'guilty,' 'not guilty,' or 'not proven.'

2. The Magistrate's Court or Petty Sessions is also a court of preliminary inquiry. The prisoner may be dealt with summarily, as, for example, in minor assault cases, or, if the case is of sufficient gravity, and the evidence justifies such a course, may be committed for trial. The fee for a medical witness who resides within three miles of the court is ten shillings and sixpence; if at a greater distance, one guinea.

In the Metropolis the prisoner in the first instance is brought before a magistrate, technically known as the 'beak,' who, in addition to being a person of great acumen, is a stipendiary, and thus occupies a superior position to the ordinary 'J.P.,' who is one of the great unpaid. In the City of London is the Mansion House Justice-Room, presided over by the Lord Mayor or one of the Aldermen. The prisoner may ultimately be sent for trial to the Central Criminal Court, known as the Old Bailey, or elsewhere.

3. Quarter Sessions.—These are held every quarter by Justices of the Peace. All cases can be tried before the sessions except felonies or cases which involve difficult legal questions. In London this court is known as the Central Criminal Court, and it also acts as the Assize Court. In Borough Sessions a barrister known as the Recorder is appointed as sole judge.

4. The Assizes deal with both criminal and civil cases. There is the Crown Court, where criminal cases are tried, and there is the Civil Court, where civil cases are heard. Before a case sent up by a lower court can be tried by the judge and petty jury, it is investigated by the grand jury, which is composed of superior individuals. If they find a 'true bill,' the case goes on; but if they 'throw it out,' the accused is at liberty to take his departure. At the Court of Assize the prisoner is tried by a jury of twelve. In bringing in the verdict the jury must be unanimous. If they cannot agree, the case must be retried before a new jury. At the Assize Court the medical witness gets a guinea a day, with two shillings extra to pay for his bed and board for every night he is away from home, with his second-class railway fare, if there is a second class on the railway by which he travels. If there is no railway, and he has to walk, he is entitled to threepence a mile for refreshments both ways.

5. Court of Criminal Appeal.—This was established in 1908, and consists of three judges. A right of appeal may be based (1) solely on a question of law; (2) on certificate from the judge who tried the prisoner; (3) on mitigation of sentence.

Speaking generally, in the Superior Courts the fees which may be claimed by medical men called on to give evidence are a guinea a day if resident in the town in which the case is tried, and from two to three guineas a day if resident at a distance from the place of trial, this to include everything except travelling expenses. The medical witness also receives a reasonable allowance for hotel and travelling expenses.

If a witness is summoned to appear before two courts at the same time, he must obey the summons of the higher court. Criminal cases take precedence of civil.

A medical man has no right to claim privilege as an excuse for not divulging professional secrets in a court of law, and the less he talks about professional etiquette the better. Still, in a civil case, if he were to make an emphatic protest, the matter in all probability would not be pressed. In a criminal case he would promptly be reminded of the nature of his oath.

A medical man may be required to furnish a formal written report. It may be the history of a fatal illness or the result of a post-mortem examination. These reports must be drawn up very carefully, and no technical terms should be employed.

No witness on being sworn can be compelled to 'kiss the book.' The Oaths Act (51 and 52 Vict., c. 46, § 5) declares, without any qualification, that 'if any person to whom an oath is administered desires to swear with uplifted hand, in the form and manner in which an oath is usually administered in Scotland, he shall be permitted to do so, and the oath shall be administered to him in such form and manner without further question.' The witness takes the oath standing, with the bare right hand uplifted above the head, the formula being: 'I swear by Almighty God that I will speak the truth, the whole truth, and nothing but the truth.' The presiding judge should say the words, and the witness should repeat them after him. There is no kissing of the book, and the words 'So help me, God,' which occur in the English form, are not employed. It will be noted that the Scotch form constitutes an oath, and is not an affirmation. The judge has no right to ask if you object on religious grounds, or to put any question. He is bound by the provisions of the Act, and the enactment applies not only to all forms of the witness oath, whether in civil or criminal courts, or before coroners, but to every oath which may be lawfully administered either in Great Britain or Ireland.

A witness engaged to give expert evidence should demand his fee before going into court, or, at all events, before being sworn.

With regard to notes, these should be made at the time, on the spot, and may be used by the witness in court as a refresher to the memory, though not altogether to supply its place. All evidence is made up of testimony, but all testimony is not evidence. The witness must not introduce hearsay testimony. In one case only is hearsay evidence admissible, and that is in the case of a dying declaration. This is a statement made by a dying person as to how his injuries were inflicted. These declarations are accepted because the law presumes that a dying man is anxious to speak the truth. But the person must believe that he is actually on the point of death, with absolutely no hope of recovery. A statement was rejected because the dying person, in using the expression 'I have no hope of recovery,' requested that the words 'at present' should be added. If after making the statement the patient were to say, 'I hope now I shall get better,' it would invalidate the declaration. To make the declaration admissible as evidence, death must ensue. If possible, a magistrate should take the dying declaration; but if he is not available, the medical man, without any suggestions or comments of his own, should write down the statements made by the dying person, and see them signed and witnessed. It must be made clear to the court that at the time of making his statement the witness was under the full conviction of approaching or impending death.