“The human body is full of fluids. Up to 60 percent of it is made up of water, nearly three-quarters in the brain and heart, more in the lungs, muscles and kidneys; even our bones are 30 percent water. As well as a container for around 5 litres of blood, our bodies are houses for mucus, milk, semen, bile, and gastric fluids and expel up to 2 litres of urine per day and half a kilogram of excrement, as well as sweat, phlegm, earwax, saliva, and tears. In order to produce these fluids, the human body needs to ingest between 2 and 3 litres of water per day, and cannot normally survive more than a few days without it. Bodily fluids, then, are a fundamental and vital part of our biology: they need to be carefully regulated to keep us healthy, and we need to keep a close eye (and sometimes nose) on the fluids that enter our body, as well as the ones that leave it. The body’s orifices—mouth, nostrils, ear canals, tear ducts, nipple ducts, and the pores of our skin, as well as the vagina, urinary tracts, and anus —regulate those fluids and function as barriers, both potent and vulnerable, that control the physical and social integrity of the body. As well as governing our basic survival, it is little surprise that these fluids and their functions lie at the very heart of socialised behaviour, intersecting closely with approaches to gender, sexuality, emotions, and morals. “