delivered the opinion of the court.
*4882. Brokers, § 84 * —admissibility of evidence. In an action for brokerage commissions for procuring an exchange of real estate owned by defendant, where it appeared that another broker with whom the property was also listed, consummated the exchange, held that a carbon copy of a letter written by plaintiff to defendant after the exchange had been consummated, in which he stated a history of the dealings and relations of the parties and expressed surprise at the “clandestine" manner in which the negotiations had been carried on, etc., was a self-serving document and apparently written in preparation of making a claim against defendant for commissions, and held that its admission in evidence on behalf of plaintiff tended to prejudice the jury in favor of plaintiff.
3. Brokers, § 99*—when instruction on amount of compensation erroneous. In an action in the Municipal Court for commissions in procuring an exchange of real estate for defendant, where there was no special agreement as to the rate of the commissions, the giving of an oral charge to the jury in which they were told that if they found the issues for plaintiff their verdict must be for a certain sum, which was computed at a certain rate on the trade value, held error where there was testimony that the rate used in computing the sum was the customary charge, but where there was no testimony of the custom on what that rate was figured, whether on the actual or trade value, and where there was testimony as to the custom, whether said rate was figured on the value of the property less the mortgage or not