It was formerly held that an objection to a witness was waived, by permitting him to be sworn. (1 Ld. Iiaym, 780.) But the modern practice of Westminster hall to swear the witness in chief in the first instance, and then to take the objection during the trial, if eventually he should appear to be interested, is founded in sound sense and reason. This mode has obtained “princpally for the convenience of the court, and it is for the furtherance of justice. ” (1 Term Bep. 719.) The same practice has been adopted by our courts, and we think the exception has been taken in due time. Though a witness has been examined an hour together at law, if in any part of his evidence it appears that he was a party interested, the court will direct the jury that he is no witness, nor any regard to be had to his testimony. 2 Vein. 161. 1 Equ. Ca. Ab.^l. 12 Vin. 12.

The plaintiffs hereupon suffered a nonsuit.