The treasurer of the county in which the drainage district, or the largest portion thereof, is situated, shall be ex officio treasurer of the district for the purposes of collecting and disbursing taxes or assessments. The treasurers of the counties in which the smaller parts of the district shall be situated shall pay over to him any and all funds collected and paid over to them for the benefit of the drainage district, and shall take the receipt of the treasurer therefor in duplicate. The original receipt the treasurer paying the money shall keep for his own protection, and the duplicate shall be filed in the office of the clerk of the county of which the person receiving such money shall be treasurer. It shall be the duty of the treasurer, who is ex officio treasurer of the drainage district, to pay any money in his hands, collected as aforesaid, upon warrants signed by the chairman and attested by the secretary of the board of supervisors of the district, when the same shall be presented for payment.