Out With The Old and in With the Euro

There are few things more banal and downright grubby than paper money and small change. In an era of electronic commerce, serious capital — the stuff that buys shares in companies, builds factories or pays a mortgage — flits unseen from one bank account to the next.

The cash in your pocket is for groceries and train tickets, for a schoolchild's spending money or a handout to a beggar. It gets rolled up for snorting drugs, or lost for years under sofa cushions. Shop clerks and bank tellers at the end of the day have to scrub...