Mo. Rev. Stat. § 50.060

50.060. County commission may borrow money — amount (first and second class counties). — The county commission of counties of classes one and two may borrow money in anticipation of the collection of taxes and revenues for the current fiscal year. The amount of such loans shall at no time exceed ninety percent of the estimated collectible taxes and revenues for the year yet uncollected. The county commission shall determine the amount and terms of such loans, and shall execute and issue warrants of the county for all money so borrowed to the lenders thereof as evidence of such loans and of the terms of the county's obligation to repay the same; and immediately before their delivery to such lenders such warrants shall be registered in the office of the clerk of the county commission, and upon delivery shall also be registered in the office of the county treasurer by entry upon the books provided pursuant to section 50.220 , correctly stating the date, amount, serial number, in whose favor drawn, by whom presented and the date presented to the treasurer for registration, and such warrants so issued and registered in connection with such loans shall have preference and priority in payment, from the date of their registration by the treasurer over all warrants subsequently issued, and over all prior issued and then unregistered warrants.

(RSMo 1939 § 10930, A.L. 1945 p. 603, A. 1949 H.B. 2007)