Scientific American Supplement, No. 1178, June 25, 1898

Fourth, and finally, those who divide human culture according to the food supply consider that the highest stage is reached through commerce. Commerce brings to all the great centers of human life the food essential to their sustenance. It would be absolutely impossible--obviously so--to have a city like Philadelphia in existence for a month without constant and ceaseless commerce brought here the food for its inhabitants. It is quite likely that, were Philadelphia shut off at once from all connection with the world, within ten days there would be an absolute famine here--so closely do we depend upon our commercial supplies for our subsistence. These supplies are not drawn from any one locality; were we to draw a radius of five hundred miles around our great city of a million inhabitants, we should still find that