§ 231. Pari-mutuel betting on horse races legalized. In the exercise of the authority vested in it by section nine of article one of the state constitution, as amended by vote of the people at the general election in November, nineteen hundred thirty-nine, the legislature prescribes that pari-mutuel betting on horse races shall be lawful in this state if conducted in the manner and subject to the conditions and supervision provided by this chapter, notwithstanding the provisions of any other law, general, special or local, prohibiting or restricting lotteries, pool-selling or bookmaking, or any other kind of gambling; it being the purpose of this chapter to derive from such betting as herein authorized a reasonable revenue for the support of government and to promote agriculture generally and the improvement of breeding of horses particularly in the state. Such pari-mutuel betting shall only be conducted within the grounds or enclosure of a racetrack on races at such track and on such dates when racing at such track shall have been authorized pursuant to this chapter; provided, however, that nothing in this section shall be deemed to prohibit off-track pari-mutuel betting in a municipality pursuant to article five, five-A or six of this chapter.