The way in which independent living beings build such an organic machine may be defined as “division of labor.” Every organism is a union, founded on the division of labor, between a multitude of kindred individuals which thus combine their isolated forces. But a large mass of individuals cannot merge at once into an all-embracing entity. This result can only be reached by a series of higher and lower intermediary units, each defined by its particular share of the total labor. A closer study of the organisms will show that they all without exception are composed in this way. The cells in any organism in nature combine into higher and higher units as follows: The primary unions of the cells are the tissues, where all the cells perform the same function in the same way. Of these tissues is formed the nearest higher unit, the organ. As the tissue was a union of cells, the organ is a union of tissues. Then we have a system of organs. To each such higher system a more comprehensive function is assigned. By distributing the total labor among the different systems these merge into the organism which unites the whole cell-mass into one well-organized community of working cell-individuals. Human society is similarly composed. The difference is only that in one case the citizens are cells, and in the other they are men. Of an organism in nature we only see the members and organs, but not the cells; in human society, on the other hand, we only observe the cells or the human individual, but not the body of society. The cells combine into a solid body; humanity is spread over a surface. Human individuals, because of their greater perfection, move in space more freely and independently of each other than do the cells in their realm. These and other differences do not, however, disturb the general organic structure. This has everywhere the same fundamental qualities. Society is essentially only a vastly enlarged copy of the same model that man traces in his own bodily organism. Through a similar division of labor the work of the community is split into trades, corresponding to the tissues in the natural organism. As the cells in one tissue, so the men in one trade are incessantly occupied with the same work. Out of several trades are formed the social organs. A social organ consequently is a certain community or district performing a certain part of an industry. This has been called “territorial division of labor.” Several such communities make up an organ-system or an industry. A few such larger units merge into the single unit, the entire mass of human individuals as a whole.