Okla. Stat. tit. 21, § 1151
Every person has the right to direct the manner in which his body shall be disposed of after his death, and to direct the manner in which any part of his body which becomes separated therefrom during his lifetime shall be disposed of. The provisions of this article do not apply where such person has given directions for the disposal of his body or any part thereof inconsistent with these provisions.
R.L. 1910, § 2446.