Power to admit or call for new evidence for prosecution. Accused's right to adjournment

If it appears necessary before the close of the case for the prosecution, the commissioner may, in his discretion allow the prosecutor to produce evidence not included in the list given to the person accused, or may itself call for new evidence and in such case the person accused shall be entitled to have, if he demands it, an adjournment of the proceedings for seven clear days, before the production of such new evidence exclusive of the day of adjournment and of the day to which the proceedings are adjourned.