Opinion of expert on point of science, or art, or foreign law

(1) Where there is a question as to any point of science or art, the opinion upon that point of a person specially skilled in the science or art is admissible in evidence. (2) That person is hereinafter called “an expert”. (3) The words “science or art” include all subjects on which a course of special study or experience is necessary to the formation of an opinion and, amongst others, the examination of handwriting. (4) Where there is a question as to a foreign law, the opinion of an expert, who in his profession is acquainted with that law, is the only admissible evidence thereof, though the expert may produce to the court books which he declares to be works of authority upon the foreign law in question, and those books, the court having received all necessary explanations from the expert, may construe for itself. (5) It is the duty of the judge to decide whether the skill of any person in the matter on which evidence of his opinion is offered is sufficient to entitle him to be considered as an expert. (6) The opinion of an expert as to the existence of the facts on which his opinion is to be given is inadmissible unless he perceived those facts himself.