When the reason of a rule ceases, so should the rule itself.
§ 1-3-201, MCA
En. Sec. 4601, Civ. C. 1895; re-en. Sec. 6178, Rev. C. 1907; re-en. Sec. 8739, R.C.M. 1921; Cal. Civ. C. Sec. 3510; Field Civ. C. Sec. 1965; re-en. Sec. 8739, R.C.M. 1935; R.C.M. 1947, 49-102.