Figure 12-6 pulls together in a simplified way the main elements of income determination. Without saving and investment, there would be a circular flow of income between business and the public: above, business pays out wages, interest, rents, and profits to the public in return for the services of labor and property; and below, the public pays consumption dollars to business in return for goods and services.
Realistically, we must recognize that the public will wish to save some of its income, as shown at the spigot Z. Hence, businesses cannot expect their consumption sales to be as large as the total of wages, interest, rents, and profits.

8th ed., 1970, p. 218 - Economics (1948-2009)