We should not understand that either social or private objective incomes include only material goods, for many utilities and labor services that never take on a material or money expression are included in either case. Indeed, we are close here to the conception of psychic income which is to be developed more fully. [Sidenote: Money income] Income of money is not often the same as income of things. Usually many of these subtler utilities are overlooked and omitted from the recognized money income. In this day the use of money is so common that we are sometimes led to ignore the value of things to which the money expression is not given. The money income is merely the money expression of the value of currently acquired goods, and it is the only medium through which such varied sources of gratification can be compared. [Sidenote: Gross and net income] 4. _Income in the logical sense must be a net addition, but the term gross income is not without popular and practical meaning._ Gross income is sometimes spoken of in the sense of total receipts, as the total of goods secured; net income is the remainder after deducting expenditures and after replacing the goods employed to secure the income. In order to produce some goods technically, men make use of other goods. While they are storing up a supply of wood or coal it may be looked upon as the income, but they may burn it to help grow hothouse plants. While they gather flowers with one hand, they destroy fuel with the other. Only the net increase in value can be accounted income in the second period. The goods that come into a man's possession in any period are of many sorts: to get some he has destroyed many previously existing goods; while to get others he has not needed to use up the accumulations of the past or to mortgage the future. The one kind is gross, the other net income. [Sidenote: Wealth and income] 5. _An income of consumption goods is a part of wealth, but not the whole of it._ The consumption goods, the "present goods" at the moment available, are the essential part of wealth for the moment's enjoyment. The only essential and immediate conditions of a series of gratifications is a regular series of consumption goods. But many things existing which could be used to secure a gratification are not in fact treated as consumption goods. A crop of corn is not all income. In a time of famine it could be used, but seed-corn was saved from last year, and some must be kept for next year. This is a part of wealth, but not of "present goods" as we understand the term. [Sidenote: Some goods never can become enjoyable goods]