When Jupiter was creating man, he instructed Mercury to concoct an infusion of lies and to add a small measure of it to the ingredients used in making tradesmen. Mercury complied, administering an equal portion to each in turn—the tallow-chandler, the greengrocer, the haberdasher, and all the others. When he finally reached the horse-dealer, who was last on the list, he found he still had a considerable quantity of the infusion remaining. So, he poured all of it into him. This explains why all tradesmen are prone to lying to some degree, but none can match the horse-dealer in deceit.