In the sixteenth century, Jesuit missionaries returning from South America brought home a powder with the power to heal a deadly disease then rampant in Europe No wonder the English memsahibs became so fond of a gin and tonic. In the days of empire, malaria was always a threat, even if your bed was surrounded by mosquito nets. So a dose of quinine – a staple of Indian tonic water – was essential as a deterrent. The quinine you find in drinks is chemically synthesised but its name suggests its source: the term comes from ghina, or quina-quina, a Peruvian name for a medicine coming from the bark of the cinchona tree. And Peruvian bark, better known as Jesuit’s bark, was once the most important remedy for all forms of malaria.That the Jesuits were crucial in discovering a