Section 18. The assessors shall include such assessment in the tax list and warrant committed by them to the collector of taxes for that municipal year, and it shall be included in the next annual tax bill, or if the estate so assessed is otherwise exempt from taxation, it shall be rendered as a tax bill. Such assessment shall be a lien upon the estate, and shall be levied, collected, reassessed, paid, apportioned, and bear interest and become payable, in the same manner as, and shall be a part of, the tax for that year on such estate; but in cities the assessors shall make no abatement thereof except upon the recommendation of the board or officer by whom the list was certified to them.