By way of summary of what has gone before, the following general definitions of commerce may be given.

In County of Mobile v. Kimball40 the court declare: "Commerce with foreign countries and among the States, strictly considered, consists in intercourse and traffic, including in these terms navigation and the transportation and transit of persons and property, as well as the purchase, sale, and exchange of commodities."

In Gloucester Ferry Co. v. Pennsylvania41 the court say: "Commerce among the States consists of intercourse and traffic between their citizens and includes the transportation of persons and property and the navigation of public waters for that purpose, as well as the purchase, sale, and exchange of commodities."