As the plaintiffs introduced testimony to prove that the body of the note, as well as the signature, was in the defendant’s handwriting, and as proof that the former was not his writing was not irrelevant, but had some tendency to prove that the signature was not his, we are all of opinion that he was rightly- permitted to offer testimony that neither was his handwriting. He might properly rebut all the evidence from which the jury could legally infer that he signed the note. The jury were properly instructed, that the question, whether the defendant wrote the body of the note, was of no importance, except as it bore on the question whether he signed it, and that proof that he signed it was sufficient to maintain the action.'
The witness Smith, who was called as an expert, was rightly allowed to give the reasons for the opinion that he expressed. This point was adjudged in Commonwealth v. Webster, 5 Cush. 301. And in Collier v. Simpson, 5 Car. & P. 73, Tindal, C. J. ruled that counsel might ask a witness, who was called to testify as an expert, “ his judgment and the grounds of it.” The value of an opinion may be much increased or diminished, in the estimate of the jury, by the reasons given for it.
We are of opinion that the testimony of Albro was competent, and that its weight and effect were properly left to be judged of by the jury. He had done business with the defendant, and had seen him write, and could form an opinion of his handwriting. There could be no doubt, on the authorities, of the admissibility of this testimony, if the knowledge, which the witness had of the defendant’s handwriting, had not been acquired after the date of the note in question. The objection is, that the defendant, in his business with the witness, and in writing in his presence, may have had this note in mind, and have written differently from his usual manner, for the purpose of making evidence for himself in this case, or that the character of his writing may have changed since the date of the note. All this, however, was for the consideration of the jury.
It has been held that a witness shall not be permitted to testify that in his opinion a signature to an instrument in suit *458is not that of the defendant, when his only knowledge of the defendant’s handwriting is derived from seeing him write his name, for the purpose of showing to the witness his true manner of writing, so that the witness might be able to distinguish it from the signature to an instrument in question. Stranger v. Searle, 1 Esp. R. 14. But we are not aware of any decision, or of any recognized principle of evidence, which would exclude Albro’s testimony. It may have been entitled to very little weight; but its competency is the only question before us. See 2 Phil. Ev. (New York ed. 1849,) 248, 249; Glassford on Ev. 555, 556.
The evidence that was offered of the female’s handwriting, for the purpose of showing that she did not write the note in question, was clearly irrelevant, and was therefore rightly excluded.
Judgment on the verdict.