SECTION 1. Subsection (b) of section one of Act Numbered Fifteen hundred and thirty-seven, as amended by section one of Act Numbered Fifteen hundred and ninety-nine and section one of Act Numbered Eighteen hundred and four, is hereby further amended by adding at the end thereof the following:
"Provided, That the Philippine Antituberculosis Society is permitted to hold horse races, with betting, for charitable purposes, on the second Sunday of March, the third Sunday of June, and the third Sunday of October of the year nineteen hundred and thirty-three only: Provided, further, That during the remainder of the year nineteen hundred and thirty-two, the Antituberculosis Society may hold horse races on the third Sunday of October and the third Sunday of November: Provided, further, That all profits from the holding of such races, after deducting the expenses, not to exceed fifteen per centum of the gross earnings plus the prizes for the horses, which shall not exceed those usually given for races of this kind, shall accrue exclusively to the funds of the Philippine Antituberculosis Society: And provided, finally, That said Society shall be exempt from the payment of municipal and insular taxes for holding said races."