The verdict shall be written, signed by the foreman and read by the clerk to the jury, and the inquiry made whether it is their verdict. If any juror disagrees, the jury must be sent out again; but if no disagreement be expressed, and neither party requires the jury to be polled, the verdict is complete and the jury discharged from the case. If, however, the verdict be defective in form only, the same may, with the assent of the jury, before they are discharged, be corrected by the court.