The problem with private banks issuing notes is that there would periodically be banking crises when the banks failed to pay on their notes and they couldn't pay out the gold that was demanded--that was required.

私有银行发行纸币的问题在于,当它们没法用要求的金子-规定的金子数量,支付它们发行的纸币时,它们将周期性的,陷入银行业危机。

耶鲁公开课 - 金融市场课程节选

They basically all failed and were taken over by foreign banks after the Mexican Crisis, so that's a sign of how things can go amiss.

他们已然全数破产并于,墨西哥银行业危机,之后被外国银行接管,这正是事态发展恶劣程度的标志

耶鲁公开课 - 金融市场课程节选

People were pulling money out of banks because they feared that if the bank failed, then they would lose their money; it created a huge crisis in 1933.

人们纷纷从银行提取现金,因为他们担心,万一银行破产,他们就会血本无归,这种情况导致了1933年经济危机

耶鲁公开课 - 金融市场课程节选