Opinions of third persons when relevant
—(1) When the court has to form an opinion upon a point of foreign law or of science or art, or as to the identity or genuineness of handwriting or finger impressions, the opinions upon that point of persons specially skilled in such foreign law, science or art, or in questions as to the identity or genuineness of handwriting or finger impressions, are relevant facts.
(2) Such persons are called experts.
The question is whether the death of A was caused by poison.
The opinions of experts as to the symptoms produced by the poison by which A is supposed to have died are relevant.
The question is whether A, at the time of doing a certain act, was by reason of unsoundness of mind, incapable of knowing the nature of the act or that he was doing what was either wrong or contrary to law.
The opinions of experts upon the question whether symptoms exhibited by A commonly show unsoundness of mind, and whether such unsoundness of mind usually renders persons incapable of knowing the nature of the acts which they do or of knowing that what they do is either wrong or contrary to law, are relevant.
The question is whether a certain document was written by A. Another document is produced which is proved or admitted to have been written by A.
The opinions of experts on the question whether the 2 documents were written by the same person or by different persons are relevant.
48. Facts not otherwise relevant are relevant if they support or are inconsistent with the opinions of experts when such opinions are relevant.
The question is whether A was poisoned by a certain poison.
The fact that other persons who were poisoned by that poison exhibited certain symptoms, which experts affirm or deny to be the symptoms of that poison, is relevant.
The question is whether an obstruction to a harbour is caused by a certain sea-wall.
The fact that other harbours similarly situated in other respects but where there were no such sea-walls began to be obstructed at about the same time is relevant.
49. When the court has to form an opinion as to the person by whom any document was written or signed, the opinion of any person acquainted with the handwriting of the person by whom it is supposed to be written or signed, that it was or was not written or signed by that person, is a relevant fact.
Explanation .—A person is said to be acquainted with the handwriting of another person when he has seen that person write, or when he has received documents purporting to be written by that person in answer to documents written by himself or under his authority and addressed to that person, or when, in the ordinary course of business, documents purporting to be written by that person have been habitually submitted to him.
The question is whether a given letter is in the handwriting of A, a merchant in London.
B is a merchant in Singapore, who has written letters addressed to A and received letters purporting to be written by him. C is B’s clerk, whose duty it was to examine and file B’s correspondence. D is B’s broker, to whom B habitually submitted the letters purporting to be written by A, for the purpose of advising him thereon.
The opinions of B, C and D on the question whether the letter is in the handwriting of A are relevant, though neither B, C nor D ever saw A write.
50. When the court has to form an opinion as to the existence of any general custom or right, the opinions as to the existence of such custom or right of persons who would be likely to know of its existence, if it existed, are relevant.
Explanation .—“General custom or right” includes customs or rights common to any considerable class of persons.
The right of the inhabitants of a particular kampong to use the water of a particular well is a general right within the meaning of this section.
51. When the court has to form an opinion as to —
the usages and tenets of any body of men or family;
the constitution and government of any religious or charitable foundation; or
the meaning of words or terms used in particular districts or by particular classes of people,
the opinions of persons having special means of knowledge thereon are relevant facts.
—(1) When the court has to form an opinion as to the relationship of one person to another, the opinion expressed by conduct as to the existence of such relationship of any person who as a member of the family or otherwise has special means of knowledge on the subject is a relevant fact.
(2) Such opinion shall not be sufficient to prove a marriage in prosecutions under section 494, 495 or 498of the Penal Code (Cap. 224).
(a) The question is whether A and B were married.
The fact that they were usually received and treated by their friends as husband and wife is relevant.
The question is whether A was a legitimate son of B.
The fact that A was always treated as such by members of the family is relevant.