If there was any error in admitting, on the first day of the trial, secondary evidence of the contents of the two etters from the witness Wood to the defendant, it was cured by *288the production by the defendant on the second day of jbhe original letters. They were then put in evidence in the place of the secondary evidence of their contents, which thus became immaterial.
The verdict of the jury has rendered the defendant’s exception to the exclusion of the evidence offered to prove the custom of brokers in Boston immaterial, they having found that the defendant was not guilty on the second count.
The findings on the two counts import that there was no order by Wood “to buy stocks on margin,” and therefore the customs offered do not apply to the facts as proved. But if there had been an-order by Wood “to buy stocks on margin,” we think that evidence of the custom contained in the second offer of the defendant would be inadmissible. When a man gives an order to a broker “ to buy stocks on margin,” he employs the broker to act for him and in his interest; the broker has no right to put himself in a position antagonistic to the interests of his employer ; he cannot make himself both buyer and seller, and any custom to this effect, unknown to the employer, is against 'public policy, and illegal. Farnsworth v. Hemmer, 1 Allen, 494.
The defendant further contended that his contract with Wood “was a gambling contract, and was illegal under the statute; and that, even if he had appropriated the margin, he could not be convicted of embezzlement.” There was no evidence that Wood contemplated, or authorized the defendant to enter into, any gambling or illegal contract. If he had, the check or money sent by him would remain the subject of larceny or embezzlement ; and if the defendant fraudulently appropriated it to his own use, it would be no defence to an indictment by the government for embezzlement to show that the property had been entrusted to him for an illegal purpose. Commonwealth v. Smith, 129 Mass. 104.
Exceptions overruled.