Francisco Hernández expedition (1570–1577)

Among some of the most important achievements of the expedition were the discovery and subsequent introduction in Europe of a number of new plants that did not exist in the Old World, but that quickly gained acceptance and become very popular among European consumers, such as pineapples, cocoa, corn, and many others.

Expedition

In 1570 Hernández was appointed Archiater physician for the New World and commended by the King to embark on a scientific expedition to study the region's medicinal plants. Hernandez set sail for the New World in August 1571, taking along his son, and landed in February 1572 in Veracruz. For three years he toured Mexico and Central America together with a geographer, painters, botanists and native doctors, collecting and classifying botanical specimens. He also studied the culture and medical achievements of the native Nahua peoples, taking notes and preparing numerous illustrations assisted by three indigenous painters who had been baptized as Antón, Baltazar Elías and Pedro Vázquez.

Among the plants the expedition encountered and described were pineapples, cocoa (known by the locals as Cacahuatl), corn, Guaiacum officinale, Smilax regelii, Strychnos nux-vomica (known by the locals as Mahuatl Quauhtlepatli), sweet granadilla, passionfruit, and several plants with hallucinogenic properties used in rituals such as peyote, maguey, and Datura or devil's weed.

From March 1574 until his return to Spain in 1577, Hernandez lived in Mexico, where he carried out medical tests using the plants he had gathered, put together a large botanical collection, and studied local medicinal practices and archeological sites. The result was an impressive work, composed of 24 books on plants, one about the fauna, one on minerals, and ten volumes of paintings and illustrations that were brought to Spain to be published. José de Acosta calculated that the total cost of the expedition represented about 60,000 ducats, an enormous sum at the time.

During the 1576 outbreak of the epidemic known as cocoliztli, Nahuatl for "pest", during the colonial-period population decline of the Aztecs, Hernández performed autopsies in the Hospital Real de San José de los Naturales in collaboration with surgeon Alonso López de Hinojosos and physician Juan de la Fuente. Hernandez described the gruesome symptoms with clinical accuracy. These included high fever, severe headache, vertigo, black tongue, dark urine, dysentery, severe abdominal and thoracic pain, large nodules behind the ears that often invaded the neck and face, acute neurologic disorders, and profuse bleeding from the nose, eyes, and mouth, with death frequently occurring in 3 to 4 days.