Medicinal leeches, two, in glass specimen jar, probably British variety, 19th to early 20th century

Leeches were used in bloodletting – a practice once carried out to treat a wide range of diseases and medical conditions. This jar was used to hold leeches which would have been on sale to medical practitioners. They are a type of worm with suckers at both ends of the body although only the frontal sucker, which has teeth, is used to feed. Once attached to a living body, they feed on blood.

Leeches were such a popular treatment that by 1830 their demand outstripped the supply. Leeches are again being used today following plastic and reconstructive surgery as they help restore blood flow and circulation.