The presiding judge properly ruled that the burden of proof was on the plaintiffs to show that the price of the goods sold was due and payable at the time of instituting the present action. The further ruling, that the plaintiffs were not entitled to offer additional evidence as affirmative proof of their original case, after the evidence of the defendants had been closed, furnishes no legal gfound for exceptions. If admitted at all, it is a matter within the discretion of the court, and is admissible under peculiar circumstances requiring it. Its rejection furnishes no cause for exception. Morrison v. Clark, 7 Cush. 213. York v. Pease, 2 Gray, 282. Exceptions overruled.