“This was an action on the case brought by the plaintiff against the defendant in the Circuit Court of the District of Columbia, upon a contract in writing, entered into between the plaintiff and defendant, for the sale of bank stock of the Central Bank of Georgetown. At the time that this contract was entered into, each party had a counterpart of the contract, and the plaintiff alleging the loss of his, he gave notice to the defendant to produce, upon the trial, the one which he, the defendant, had; but the defendant declined producing it, stating that he had lost his also. In consequence of these losses, the plaintiff, upon the trial of the cause, offered to prove, by a person who was witness to the contract, and had subscribed it as such, the contents of the contract, and to entitle himself to give this testimony.”