The Incas had no written language and their chroniclers say little about their surgery and nothing about their methods for relieving the pain it caused. It is possible that they did have some form of anesthesia. Available plants that had central effects include maize (which they used in different ways to prepare an alcoholic beverage called chicha), Datura, espingo, tobacco, San Pedro cactus, and coca. The Incas used chicha to induce unconsciousness during minor surgical operations and it was still being used in those regions in the 19th century to perform female circumcision. Datura, espingo, tobacco, and San Pedro cactus can produce a deep trance and, in all probability, anesthesia. There is evidence that they used Datura as a total or partial anesthetic. The Incas chewed coca leaves with lime and swallowed the resulting juice, and this allowed them to work long hours without eating or drinking. Modern-day Peruvian Indians say that coca only numbs the mouth, though it was observed in the 19th century that coca leaves placed in wounds provided pain relief. It is possible that the Incas used chicha - probably in combination with another narcotic - to achieve the total or partial anesthesia needed for their surgery. A decoction of coca leaves may have been used as a topical anesthetic.