Cultural historian and curator Mike Jay has made a study of the global role of mind-altering substances. “For me, it’s the most fascinating corner of our relationship with plants. I find it extraordinary in terms of both botany and biochemistry that so many plants contain alkaloids that correspond to our brain neurochemistry and can change the way that we think and feel, our moods and our perceptions. Their use is so universal, and informs so many different areas – botany, anthropology, ethnography, psychology, science, art, literature – it opens a window on to the whole span of human culture.”