The county treasurer of the county coextensive with such district shall be ex officio treasurer of the health district. He shall attend all meetings of the board when required to do so, shall prepare and submit in writing a monthly report of the state of its finances, and shall pay out its money only upon a warrant signed by the president, or in his absence by the vice president, and countersigned by the secretary. He shall give bond, payable to the health district, in the amount of one hundred thousand dollars. Such bond shall be signed by one or more surety companies of recognized responsibility and authorized to do business in this state. The cost of the bond shall be paid by the health district.