some industries the tendency is one way, and in some the other. In still others it is merely a question of how much of the work each contributor shall do. Shall the iron-master buy his iron in the bar, in the pig, or in the ore? Shall the woolen manufacturer buy his wool in the crude web, in the yarn, or in the fleece? Fifty years ago it was quite common for the same family to rear and shear the sheep, wash the fleece, card it, spin it, weave it, color it, and make it into clothing—though different members of the family attended to different parts of the work. That was a combination of the second form. At present wool-growing and woolen-manufacturing are separated. Sometimes the spinning and weaving are separated. As a rule, the weaving and making are separated.
It is into this third form of combination that what is called exchange enters. Exchange is so important a phenomenon that political economy is often called the science of exchanges. This definition, as we now see, narrows its field. The real subject-matter of political economy is the mutual helpfulness of human beings in making a living. Exchange is only one of the ways of making this helpfulness effective. None the less, persons between whom exchange is hindered or prohibited are to that extent kept from helping one another to make a living. The wool-grower and the sheep-shearer are just as truly engaged in the production of cloth as the weaver. If the wool-grower is prohibited from furnishing wool to the weaver, it is plain that both are hindered in their joint work.
4. In the fourth form of combination, also, exchange prevails as a prominent feature. But here we take leave of one feature which has thus far characterized all forms of combination. It is unity of product. Each party now completes his product, ready to enter into the living of a fellow-being. One hunts and the other fishes, and the hunter trades game for fish. Each then has for his supper a variety consisting of game and fish. Rarely, indeed, is the exchange so simple as this. In civilized societies it is highly complex, and its problems baffle the best of brains. If we sit down to a meal, we find that one set of men have furnished us the table, another set the table-cloth, another the dishes, another the silver, another the bread, another the butter, another the pepper, another the salt, another the sugar, another the coffee, another this, and another that, until a score of groups and thousands of persons might be counted, all of whom have helped us to get our dinner—to make our living.
5. There is a fifth form of combination, more simple than the third or fourth, and yet in one sense more complex. In this the service rendered on one side is direct, and on the other indirect. There is no exchange of products, and, in fact, generally no product. The physician, the minister, the lawyer, the teacher, and the housemaid, all help us in making a living. They do not help us by making some material thing and sending it to us. They help us personally and directly. We in
