Mo. Rev. Stat. § 89.040
Such regulations shall be made in accordance with a comprehensive plan and designed to lessen congestion in the streets; to secure safety from fire, panic and other dangers; to promote health and the general welfare; to provide adequate light and air; to prevent the overcrowding of land; to avoid undue concentration of population; to preserve features of historical significance; to facilitate the adequate provision of transportation, water, sewerage, schools, parks, and other public requirements. Such regulations shall be made with reasonable consideration, among other things, to the character of the district and its peculiar suitability for particular uses, and with a view to conserving the values of buildings and encouraging the most appropriate use of land throughout such municipality.
§ 89.040, RSMo
RSMo 1939 § 7414, A.L. 1959 H.B. 493