Section 14. In prosecutions for forging or counterfeiting notes or bills of the banks or institutions before mentioned, or for uttering, publishing or tendering in payment as true forged or counterfeit bank bills or notes, or for being possessed thereof with intent to utter and pass the same as true, the testimony of the president and cashier of any such bank may be dispensed with, if their place of residence is out of the commonwealth or more than forty miles from the place of trial; and the testimony of any person acquainted with the signature of such president or cashier, or who has knowledge of the difference in the appearance of the true and the counterfeit bills or notes of such banks, may be admitted to prove that such bills or notes are counterfeit.