Colo. Const. art. V, § 19
An act of the general assembly shall take effect on the date stated in the act, or, if no date is stated in the act, then on its passage. A bill may be introduced at any time during the session unless limited by action of the general assembly. No bill shall be introduced by title only.
Source: Entire article added, effective August 1, 1876, see L. 1877, p. 40. L. 1883: Entire section amended, p. 21. L. 18: Entire section amended, see L. 19, p. 344. L. 50: Entire section amended, see L. 51, p. 554.