Hunter and fisher folk, relying almost exclusively upon what their land produces of itself, need a large area and derive from it only an irregular food supply, which in winter diminishes to the verge of famine. The transition to the pastoral stage has meant the substitution of an artificial for a natural basis of subsistence, and therewith a change which more than any other one thing has inaugurated the advance from savagery to civilization.[108] From the standpoint of economics, the forward stride has consisted in the application of capital in the form of flocks and herds to the task of feeding the wandering horde;[109] from the standpoint of alimentation, in the guarantee of a more reliable and generally more nutritious food supply, which enables population to grow more steadily and rapidly; from the standpoint of geography, in the marked reduction in the per capita amount of land necessary to yield an adequate and stable food supply. Pastoral nomadism can support in a given district of average quality from ten to twenty times as many souls as can the chase; but in this respect is surpassed from twenty to thirty-fold by the more productive agriculture. While the subsistence of a nomad requires 100 to 200 acres of land, for that of a skillful farmer from 1 to 2 acres suffice.[110] In contrast, the land of the Indians living in the Hudson Bay Territory in 1857 averaged 10 square miles per capita; that of the Indians in the United States in 1825, subsidized moreover by the government, 1-1/4 square miles.[111] [Sidenote: Land in relation to agriculture.] With transition to the sedentary life of agriculture, society makes a further gain over nomadism in the closer integration of its social units, due to permanent residence in larger and more complex groups; in the continuous release of labor from the task of mere food-getting for higher activities, resulting especially in the rapid evolution of the home; and finally in the more elaborate organization in the use of the land, leading to economic differentiation of different localities and to a rapid increase in the population supported by a given area, so that the land becomes the dominant cohesive force in society. [See maps pages 8 and 9.] [Sidenote: Migratory agriculture]