The name of such drainage district shall constitute a part of its corporate name; for illustration, the board of drainage commissioners of Mecklenburg Drainage District, No. 1. In the naming of a drainage district the clerk of the court, notwithstanding the name given in the petition, shall so change the name as to make it conform to the county within which the district, or the main portion of the district, is located, and such district shall also be designated by number, the number to indicate the number of districts petitioned for in the county. For illustration, the first district organized in Mecklenburg County would be Mecklenburg County Drainage District, No. 1; the name of the second would be Mecklenburg County Drainage District, No. 2; the fifth one organized would be Mecklenburg County Drainage District, No. 5: Provided, that so much of this section as provides for numbering the districts in each county shall not apply to districts in which bonds have been issued and sold prior to the fifth day of March, 1917. (1909, c. 442, s. 19; 1917, c. 152, s. 17; C.S., s. 5338.)