Leeches were used in bloodletting, a cure intended to balance the four humours. This tube was used to transport leeches from place to place and may have been used to apply them to the body. Leeches were gathered from streams and sold on by apothecaries. Leeches are a type of worm with suckers at both ends of the body; they suck blood until their bodies are engorged. Leeches are sometimes used today following plastic and reconstructive surgery as they help restore blood flow and circulation