t had not yet been made; but it was in contemplation by the
states of Virginia and Maryland to cede it. It is called the _District
of Columbia_. Its inhabitants are subject to the laws of congress. That
part of the district which was ceded by Virginia, was in 1846,
retroceded _by_ congress to that state. To congress is given, with equal
propriety, exclusive authority over all places purchased "for the
erection of forts, magazines, arsenals, dock-yards, and other needful
buildings."

Sec.10. The last power granted in this section, is the power "to make all
laws which shall be necessary and proper for carrying into execution the
foregoing powers, and all other powers vested by this constitution in
the government of the United States, or in any department or officer
thereof." As it was impossible to enumerate in the constitution every
particular act which congress might find it necessary to perform,
certain powers were expressly granted; and to these powers was added
this general grant of power to pass laws for carrying them into effect.

Sec.11. It is the opinion of eminent statesmen that this clause confers no
additional power. They hold that the power therein granted is
necessarily _implied_ or included in the foregoing powers. For example:
The power "to regulate commerce" includes the power to cause the
construction of break-waters and light-houses, the removal of
obstructions from navigable rivers, and the improvement of harbors; for
in regulating and facilitating commerce, these works and improvements
are absolutely necessary. So the power "to establish post-offices"
implies the power to punish persons for robbing the mail. The doctrine
is, "that wherever a general power to do a thing is given, every
particular power for doing it is included." Hence it is inferred that
congress would have had the power to pass the laws here authorized,
though no express power for that purpose had been given.

Sec.12. Besides the long list of powers contained in the eighth section of
the first article of the constitution, and considered in preceding
chapters, there are sundry other powers of congress in subsequent
articles, which will be noticed in their order.

Chapter XXXVII.

Prohibitions on Congress.

Sec.1. While the constitution confers on congress all the powers deemed
necessary to be exercised for the general welfare, it imposes on
congress certain restrictions, the most of which are contained in the
next sect