52:2.8

During this age agriculture makes its appearance. The growth of the family idea is incompatible with the roving and unsettled life of the hunter. Gradually the practices of settled habitations and the cultivation of the soil become established. The domestication of animals and the development of home arts proceed apace. Upon reaching the apex of biologic evolution, a high level of civilization has been attained, but there is little development of a mechanical order; invention is the characteristic of the succeeding age.