The real introductory function which deposit banks at first perform is much more popular, and it is only when they can perform this more popular kind of business that deposit banking ever spreads quickly and extensively.

This function is the supply of the paper circulation to the country, and it will be observed that I am not about to overstep my limits and discuss this as a question of currency.

In what form the best paper currency can be supplied to a country is a question of economical theory with which I do not meddle here.

I am only narrating unquestionable history, not dealing with an argument where every step is disputed.
And part of this certain history is that the best way to diffuse banking in a community is to allow the banker to issue bank-notes of small amount that can supersede the metal currency.

This amounts to a subsidy to each banker to enable him to keep open a bank till depositors choose to come to it.