The Leech House, Aiskew, North Yorkshire
This leech house was built in the late 18th century. It is a rare example of a building by a river designed for a doctor to house leeches, for use in his profession. Leeches were used to remove blood from a patient as part of a process to "balance" the "humors". The humors, according to Galen, must be kept in balance in order for the human body to function properly. They were used to treat a whole range of diseases.
