Among the least cultivated tribes of mankind, the family is wholly adequate to itself, there being no dissimilarity of industrial function, except between the husband and wife. The family builds its own hut, makes its own weapons, kills its own game--in short, provides for all its own needs. What is industrially true of one family is true of all others; there is no division of labor, no exchange of products. They have no accumulated property, no fixed habitation, but wander from place to place, as the attractions of their simple life may lead them. But when population becomes more numerous, and neither hunting nor pasturage is sufficient for their support, the cultivation of the soil is resorted to, and new wants are developed. The division of labor, the differentiation of the industrial function begins. One man cultivates the soil, another works in iron, another in wood, and so on; and these specialities, in their turn, assume new branches. Take agriculture for example: At first every husbandman grows all that he needs for himself and family; after a while he observes that his soil is better adapted to one kind of crop than another, and he devotes himself more exclusively to its cultivation. A similar result with a different crop obtains on a different soil and in a different locality; and thus do the specialities of soil and climate result in the specialization of agriculture. These diversities of occupation with reference to the soil, wood, metals, imply the exchange of products; but this must obtain to a very limited extent while neighbors are remote, and the means of travel and transportation defective. With few roads, and commerce undeveloped, there is little intercommunication, little culture, little civilization. This was the condition of Scotland as late as the middle of the eighteenth century. (Buckle.) England had some external commerce as early as the thirteenth century (Hallam), but did not send a ship of her own into the Mediterranean till the fifteenth. (Robertson.) Think of the difference between then and now!