Brown A-G CJ:

The facts and arguments appear sufficiently from the judgment.

The two appellants were convicted under s. 4(c) of the Common Gaming Houses Ordinance of assisting in carrying on a public lottery. The evidence was that in the course of a Police raid a third accused person was arrested with 50 slips of paper in her hand. These had writing on them, and were put in evidence as Exh. P3. She was arrested on a staircase leading to the first floor. And in a room on the first floor the two appellants were found seated at a table with pencils in their hands. On the table in front of them were four pieces of paper. Each document was divided into 144 squares, and in each square several numbers were written in pencil. A fifth piece of paper was also on the table. It too was divided into squares containing Chinese characters and symbols. These five documents were put in evidence collectively as Exh. P4.

The question was whether Exh. P4 included any "account, memorandum or record of stakes or wagers in or relating to a lottery", so as to raise the presumption contained in s. 9 of the Ordinance. Upon this question the prosecution called as an expert witness a Police officer from the Gambling Suppression Branch, who stated that he had three years experience as an assistant to a Chap Ji Ki promoter.

It was conceded by Mr. Bezboruah on behalf of the appellants that this witness was properly called under ss. 49 and 99 of the Evidence Ordinance. But Mr. Bezboruah contended that the effect of this witness's evidence upon the material question, viz. whether the documents contained an account or record of stakes of a lottery, amounted to no more than an expression of his expert opinion, which the learned Magistrate accepted as conclusive.

The responsibility for the determination of this question, as in the case of every question upon which expert evidence is called, rested upon the Court and not upon the expert. The business of an expert witness is to draw upon the store of his knowledge and experience in order to explain some matter which his experience should qualify him to understand. He is quite entitled to express his opinion, which indeed is the natural corollary of his explanation. But a bare expression of his opinion has no evidential value at all. Unless he gives an explanation which supplies the understanding of the subject which the Court lacks, the Court is in no better position than it was before to determine the question which it is its duty to determine, and if the Court acts upon a bare expression of the expert's opinion the determination of the question becomes that of the expert and not of the Court.

In this case the witness, after stating his qualifications to be regarded as an expert, explained how a Chap Ji Ki lottery is operated. He said that the public could choose two numbers out of the first 12 numbers, which are used twice giving 144 chances. He explained that the person making a stake writes out the two numbers of his choice and the amount of his stake on a slip of paper called a staking slip. He then passes his staking slip (with the stake money) to the collector, who compiles a schedule or record slip from the staking slips which he receives and sends the schedule to the promoter. The witness then said: "Exhibit P3 consists of 50 staking slips value $171.18. Exhibit P4 consists of four schedules and an all record slip." And in cross-examination he said: "the record slip is written in Chinese characters and symbols denoting the value of the currency used i.e. ten cents, $1, etc." It would undoubtedly have been better if the expert witness, instead of making the two flat statements "Exh. P3 consists of 50 staking slips. Exhibit P4 consists of four schedules and an all record slip", had explained the purport of the squares and the numbers in the light of the explanation which he had previously given of the role which the staking slips and the schedules play in the operation of a Chap Ji Ki lottery.