184 NATURE OF CAPITAL AND INCOME [Cuae. XI 
tion has a credit as well as a debit side, and that, as to 
income, every interaction is at once a service and a dis- 
service. 
We observed that the method of couples, fully carried out, 
reveals respectively wherein capital and income ulti- 
mately consist. We have seen that such a summation, 
applied to capital, gradually obliterates all partial rights, 
such as stocks and bonds, and leaves as the final result the 
concrete capital wealth of a community; and that when 
the method of couples is applied to income accounts, the 
“Interactions” involved disappear, leaving an uncanceled 
outer fringe of services and disservices. If the method is 
continued as far as possible in the world of objective serv- 
ices, it leaves simply the direct or final services of objec- 
tive wealth as they affect the human organism ; while, 
if the method is pushed one step further, it leaves, as the 
final income stream, simply the pleasant and unpleasant 
experiences of human consciousness. We found as one 
result of our study that so-called cost of production has no 
existence as an element of the objective income stream, and 
that, therefore, the only costs of production which are not 
also elements of income are the subjective labor and trouble 
of those engaged in that production. 
We have seen that capital and income are in many re- 
spects analogous, and are strictly correlative: that all capi- 
tal yields income and that all income flows from capital —at 
least when the term “ capital ” is used in its broader sense, 
which includes human beings. The old proposition of the 
economists, therefore, that capital is that wealth which 
yields income, is correct, although the idea that such a 
statement is restrictive, and applicable only to certain kinds 
of wealth, is incorrect. 
§2 
Since capital and income are so intimately related, it 
becomes necessary to examine in detail what their relations 
are. The chief relations between capital and income are