Acts 1965, 59th Leg., vol. 2, p. 317, ch. 722. Amended by Acts 1967, 60th Leg., p. 1736, ch. 659, Sec. 13, eff. Aug. 28, 1967.

Amended by Acts 2003, 78th Leg., ch. 390, Sec. 1, eff. Sept. 1, 2003.