A bill of health is a document issued by the consul or the public authorities of the port which a ship sails from, descriptive of the health of the port at the time of the vessel's clearance. A ''clean'' bill of health certifies that at the date of its issue no infectious disease was known to exist either in the port or its neighbourhood. A ''suspected'' or ''touched'' bill of health reports that rumours were in circulation that an infectious disease had appeared but that the rumour had not been confirmed by any known cases. A ''foul'' bill of health or the absence of a clean bill of health implies that the place the vessel cleared from was infected with a contagious disease. The two latter cases would render the vessel liable to quarantine.〔Lewis Joel, ''A consul's manual and shipowner's and shipmaster's practical guide in their transactions abroad'', 1879 (text at Google Books )〕