If the county commissioners of any such county, by reason of funds on hand, or donations, or otherwise, are able to build and establish a public hospital without issuing bonds as provided in s. 155.04, then such board of county commissioners is hereby authorized and empowered to establish such public hospital and, without any election, to levy an annual tax for the maintenance thereof, such tax not to exceed 5 mills on the dollar and to be collected in the same manner as the tax provided for in s. 155.04.