The court is of opinion that the verdict in this case is not against law, nor against evidence, nor manifestly against the weight of evidence. It cannot therefore be set aside on either of these grounds.
Nor can it be set aside on account of the alleged inability of the juror, Tilton, by reason of a severe headache, and other illness, fully to understand the evidence. There is no legal evidence in support of this allegation. The practical inconvenience would be so great, to allow parties, or their counsel, to interrogate jurors as to the grounds of their verdict, or their understanding of the evidence, or the charge of the judge, and then to make a supposed error in any of these particulars the ground of a motion for a new trial, that, upon these subjects, the law has wisely closed the mouths of jurors, by declaring them incompetent to be witnesses to impeach their own verdict. “The modern practice,” says Shaw, C. J., “has been uniform, not to entertain a motion to set aside a verdict on the ground of error, mistake, irregularity or misconduct of the jury, or any of them, on the testimony of one or more jurors; that this practice rests on sound considerations of public policy.” Chadbourn v. Franklin, 5 Gray, 312.