
    Brown and another against Downing and others.
    
      Friday, October 16.
    In ERROR.
    The grantor it! a deed is a competent witness to when he executedit he
    ERROR to the Court of Common Pleas of Cumberland county.
    One who has Fandinhisown name, hutas trustee of anothereto whom he afterwards conveyed the good witness * to prove the
    
      John Downing and others, the defendants in error,
    who were plaintiffs below, claimed the land for which this ejectment was brought, by virtue of an application, in the name.of J°?m Downing, their ancestor, dated July 25th, 1767, and a survey thereon of 150 acres, and allowance on 9th May, 1769. Pbe defendants derived their title, through several mesne conveyances, from Alexander Power to John Korne^u, and J J . 1 , from Kornegy to themselves. In the course or the trial, the plaintiffs called Alexander Shortis, as a witness. He was objected to by the defendants’ counsel, who produced a deed, dated November 6th, 1811, from Shortis to John Kornegy, ^or laud question, and insisted, that he was incompetent to impeach a title which he had conveyed. To obviate this objection, the plaintiffs then offered him to prove, on the v0{re dire, that he had purchased the land, at a commission-7 c 7 er’s sale for taxes, at the request of Kornegy, and as a trustee for his use. To this, also, the defendants’ counsel excepted, on the ground, that he was not a witness to prove his own agency, and that at all events, the evidence, if true, would not remove his incompetency. The Court over-ruled both exceptions, and having first heard the witness on the voire dire, permitted him to be sworn in chief.
    
      The Court verse a judgment for er-inferior^fourt may commit, in the course of a preliminary examination of a witness, which is totally unnecessary to his admission.
    
      
      Metzgar and Watts, for the plaintiffs in error,
    contended, that to permit a man to destroy a title which he had himself conveyed, was contrary to policy and immoral, because the evidence which he was called upon to give, shewed that he was not worthy of credit, and the maxim, nemo allegans turpitudimen suam audiendus est, applied with as much propriety to a witness as to a party. Such evidence had never received the sanction of' this Court. A grantor who has given no warranty and who consequently is not interested, is a good witness to support a title conveyed by himself. Lessee of Gratz v. Ewalt. But that was a totally, different case from this, in which the witness was called to overturn what he had been instrumental in setting up. The case of Stewart v. Richards on,
      
       in which the law was stated clearly to be, that a vendor cannot by declarations made subsequent to his deed, invalidate or impeach the title he has created; and that of Drum v. Lessee of Simpson,
      
       where it was held, that the declarations of the grantor to the grantee after the execution of a deed of trust, but before the acceptance of the deed by the grantee, and therefore before the title was complete, were evidence to alter or .contradict the trust, go very far to shew, that the testimony of Shortis ought to have been excluded. He had made an absolute conveyance of the title to one under whom the defendants claimed, and if the declarations of the grantor, subsequent to the deed, are not admissible. to invalidate his own acts, on what principle can this be done, by the testimony of the grantor himself?
    If the witness was incompetent, independently of the alleged trust, he ought not by his own testimony, to have been permitted to prove himself a trustee, and thus render himself competent. In commercial cases an agent is often allowed, from necessity, to prove the authority under which he acted; but the rule is by no means universal, and in the case of An-
      Her son v. Hayes,
      
       the Court refused to admit such evidence, declaring, that in general it would be highly dangerous to permit an agent to establish his authority by his own oath, and that there would he no security against bad men, if so broad a principle were adopted. The rule, however, is confined to mercantile cases, and does not extend to sales of lands. Lessee of Nicholson v. Mifjlin.
    
    
      Carothers, for the defendants in error,
    answered, that whether Shortis was to be viewed in the light of a trustee for Kornegy or not, he was a perfectly good witness. He was not called in order to contradict his deed, to which alone he was incompetent, but to prove, that he had not a good title when he executed it, and for this purpose, he would have been competent, provided he was willing to be sworn, even if he had given a general warranty, because he would have been swearing against his own interest. The point now raised, is neither new nor difficult. The exclusion of a witness, whose testimony tends to destroy an instrument to which he has affixed his hand, has been repeatedly decided to be confined to negotiable instruments. In Baring v. Shippen,
      
       the assignor of a bond was permitted to prove, that he had obtained it fraudulently. In the Lessee of Thompson v. White,
      
       the Court received the evidence of the grantor in a deed, to shew a breach of trust and a fraud in law in his immediate grantee, to whoxn the land had been conveyed in confidence, that he would dispose of it in a particular manner, which he failed to do ; and in England, the very point now in controversy was decided by Chief Justice Holt, in the case of Title v. Grevett.
      
       It is an objection which goes to the credibility of the witness merely. Thill. Ev. 33, 34.
    Even if the Court below were wrong in the opinion, that Shortis was a proper witness to prove his own agency, it is not the subject of a bill of exceptions ; because, being competent to establish the main point, independently of his character of trustee, no injury could have arisen from the supposed erx-or. But their opinion on that point was correct. A witness may testify to a verbal power given him, but he cannot, by his own evidence, prove a written power. Thill. Ev. 96.
    
      
      
        ZBinn. 95.
    
    
      
       2 Teates, 91,
    
    
      
       6 Binn. 47?.
    
    
      
       2 Yeates, 95.
    
    
      
       2 Yeates, 38.
    
    
      
      
        % Binn* 1H
    
    
      
       1 Dali. 425.
    
    
      
      
        LcL Baym, 1008.
    
   The opinion of the Court was delivered by

Gibson J.

It did not require the preliminary evidence of the witness, on his voire dire, to get rid of the exception to . his competency. The maxim, that a person alleging his own turpitude is not to be heard, does not apply to witnesses. r ’ r{ J . , Approvers and accomplices, are constantly witnesses, although they inevitably implicate themselves in the guilt they are called to fix on the accused ; and their avowed participation in moral turpitude goes, not to their competency, but their credibility. In civil actions, the principle is the same-. A witness to the execution of a will may be received to prove the insanity of the testator, at the time of signing. Wright, dem. Clymer v. Little, 3 Burr.1244. Lowe v. Joliffe, 1 Bl. Rep. 365. The attesting a will, under such circumstances, certainly involves the witness in as great dishonesty as can fairly be imputed to a man voluntarily appearing to disprove a title he had conveyed. But the very case was decided in Title v. Grevett, 2 Ld. Raytn. 1008. In fact, the doctrine of estoppel has never been applied to witnesses, except in the solitary instance of a person putting his name to a negotiable instrument, and thereby giving it credit with the public. Although the eminent Judge, to whom that rule owes its existence, professed to found it, as well on the civil law maxim, as the protection of negotiable papers, yet the latter is the ground on which it is sustained in Pennsylvania, and those states in which it is still retained, and accordingly we find it restrained to securities strictly negotiable. In England it is exploded altogether. In transactions strictly mercantile, where credit performs the office of money, there is sound reason for protecting paper, that approaches very near to a circulating medium ; but the protection ceases with the reason on which it is founded. Undoubtedly, a witness voluntarily appearing in a court of justice to attest facts, that at once evince his turpitude and destroy his credit, is a sad and disgusting spectacle ; yet I do not know, that on that account merely, a party ought to be deprived of the benefit of his testimony, when the interests of justice may be subserved by it.

With respect to the second point, even if it were the subject of error, I am of opinion the Court below were right. Whether or not, in buying in the land, Shortis were the agent of Kornegy, was totally immaterial. His getting rid of the objection to his competency, even if well founded in the first instance, did not depend on the establishing of an agency under Kornegy. The witness was admitted to prove he purchased as a trustee for Kornegy, and with his assent ;• and that although by his deed he transferred the legal title, yet, that he never had a beneficiary interest in the land. But as Shortis was unquestionably a witness, without the aid of the matters disclosed on his voire dire, no errors the Court might have committed, in the course of a preliminary examination, totally unnecessary to his admission, and therefore irrelevant, could be assigned here, because those errors could prejudice no one. A judgment will not be reversed because the Court gave an erroneous instruction to the jury on an immaterial point. Murrel v. Johnson’s administrator, 1 Hen. & Munf. 451; nor for admitting illegal evidence, unless the plaintiff in error could possibly have received some injury from it; as where incompetent evidence of a fact has been admitted, but the same fact has been conclusively proved by a verdict and judgment between the same parties, in which the fact was litigated and put in issue. Preston v. Harvey, 2 Hen. & Munf 55. Here the inquiry of the witness having purchased as an agent or trustee, was altogether unnecessary to the decision of the question of competency; and, therefore, if it had been conducted erroneously, the rule would apply. Was Shortis, at all events, a witness ? If he was, the plaintiff in error cannot complain of the manner of his admission.

Judgment affirmed.  