As the patterns of culture change, the problems concerning man's food supply also change. It seems rather quaint to read in Thomas Hobbes' philosophical treatise Leviathan (Hobbes 1651b) that "the Nutrition of the Commonwealth consisteth in Plenty ... conveyed by convenient conduits . . . from the two breasts of our common Mother, Land and Sea." "The Matter of this nutriment," he continued, "consisteth in Animals, Vegetals and Minerals . . . layd . . . before us, in or near the surface of the earth" and to acquire them "there needeth no more but the labor and industry of receiving them." In a similar vein, John Locke (1690), the physician-philosopher-political theorist, said that anyone could have as much of nature's food products as he could use "to any advantage of life." Whatever he could acquire by his labor would be removed from common use and would become his private property. Both Locke and Hobbes were aware that food could become the focus of intense concern and controversy among individuals and nations. Although Locke justified the acquisition of land and things through labor, he added that a person could rightly acquire only as much as he could consume "before it spoils," since "nothing was made ... for man to spoil or destroy." Indeed, whatever is beyond what one can use before it spoils "is more than his share and belongs to others." There must be "enough and as good left in common for others." That, said Locke, is what distributive justice requires. Hobbes pointed to a darker side of human nature: