Tex. Const. art. 3, § 44

COMPENSATION OF PUBLIC OFFICIALS AND CONTRACTORS; EXTRA COMPENSATION; UNAUTHORIZED CLAIMS; UNAUTHORIZED EMPLOYMENT. The Legislature shall provide by law for the compensation of all officers, servants, agents and public contractors, not provided for in this Constitution, but shall not grant extra compensation to any officer, agent, servant, or public contractors, after such public service shall have been performed or contract entered into, for the performance of the same; nor grant, by appropriation or otherwise, any amount of money out of the Treasury of the State, to any individual, on a claim, real or pretended, when the same shall not have been provided for by pre-existing law; nor employ any one in the name of the State, unless authorized by pre-existing law. (Feb. 15, 1876.)