Pedro Arias de Benavides, Secretos de Chirurgia (Valladolid, 1567)
A surgeon back from fifteen years in the Indies printed at Valladolid a book whose title page advertises "the manner in which the Indians cure sores and wounds and other afflictions in the Indies". Inside, experience beats authority: he rates maguey above the fashionable American drug wood, credits an indigenous healer with curing a viceroy his physicians had given up on, and says he kept his best remedy to himself because the physicians of Mexico had interests in the other one.
Why this wins its question: The sixteenth-century medical books of New Spain that reach an English reader are Monardes, Hernández and the Cruz-Badiano herbal; Arias de Benavides is a footnote in Spanish-language history of medicine and effectively absent in English. This object reads the 1567 Valladolid imprint itself - the British Museum copy, page by page - and quotes what is actually on the leaves: the title page selling indigenous therapeutics to Spain, the maguey steam cure on folio 43 in the first person, the admission on folio 40 that he told nobody because the physicians of Mexico had interests in the alternative, and the indigenous healer on the purge leaf who cured Viceroy Antonio de Mendoza after the physicians failed. It pairs those leaves with a 2026 peer-reviewed study, and where that study's English rendering and the printed page diverge, it says so and follows the page.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The book was printed at Valladolid in 1567 by Francisco Fernández de Córdoba, printer to the royal household, with privilege, priced on the title leaf at "real y medio en papel" and dedicated to prince don Carlos. The author names himself there as "el Doctor Pedrarias de Benauides vezino y natural dela Ciudad de Toro". The copy digitised and read for this object is the British Museum one, carrying a contemporary reader's marginalia in the outer margins.
Indigenous practice is advertised on the title page as part of what the buyer is getting, and as useful back home. The full title runs: "Secretos de Chirurgia, especial de las enfermedades de Morbo galico y Lamparones y Mirrarchia, y assi mismo la manera como se curan los Indios de llagas y heridas y otras passiones en las Indias, muy vtil y prouechoso para en España y otros muchos secretos de chirurgia hasta agora no escriptos." The claim of novelty - "hasta agora no escriptos" - is the author's own sales line and is reported here as such.
He wrote from a long American practice rather than from reading. Born at El Toro, Zamora, around 1521, he crossed to the Indies between 1545 and 1550, worked in Santo Domingo, Honduras, Guatemala and Mexico City, and spent several years at the Hospital del Amor de Dios - the pox hospital, also called de las Bubas - in Mexico City in roughly 1554-1562. The cited study notes that little is known of his professional life in Spain and that his exact date of return is unclear.
The plant he rates above all others is maguey, and he says he learned its use where it was already in use: on folio 40 he writes that "todos los indios cercanos a Mexico siembran alrededor de sus labranças este maguey", and describes it as a thistle-like plant as big as a cartwheel, of great utility "para curar enfermedades delas bubas y dolores de junturas". The cited modern study reports that he called maguey the greatest treasure of the Indies and knew no plant in the world with as many virtues.
He describes the cure as something he watched and then performed himself. On folio 43: where there was neither sarsaparilla nor guaiacum, "en su lugar curauan con ello las enfermedades de bubas, tomauan ellos (y yo ansi lo he hecho) vn grumo de aquel maguey, y hazia lo pedaços menudos, y hechaua lo en vna holla de agua grande", sealed with a plate and luted with dough so no vapour escaped, boiled three or four hours, carried to the patient and uncovered so that he received the steam and began at once to sweat. The eighteenth chapter heading in the table of contents promises the same plant for bubas and for joint pains caused by cold.
He also records that he did not share it, and says why. On folio 40: the maguey "tiene muchos prouechos que yo experimenté, y a nadie lo quise descubrir, porque los medicos de aquella tierra no están bien con él, a causa de sus interesses y prouechos" - the physicians of that land are not well disposed toward it because of their interests and profits - adding that when he discussed it with them they asked why he made so much use of it, since if a cure went wrong he would have nothing written to defend himself with, the thing being unknown. The cited modern study renders the same passage as though nobody else was willing to investigate the plant; the 1567 leaf read for this object says rather that he chose to reveal it to no one, and the imprint is followed here.
He gives a named indigenous practitioner credit for a cure European medicine had failed at. On the leaf carrying the account of purges he writes that the purges of the indio were stronger than his own because of the strength of the root, that they purged every fifteen days and so healed by evacuation, and that "este fue el indio que curó al virey don Antonio de Mendoça, no le pudiendo ya curar los medicos, y lo lleuo de alli donde estaua catorze leguas" - the viceroy being ill of a mirarchia, which he says is difficult to cure in those parts. The printed folio number on that leaf is cropped in the scan, so the claim is bound to the leaf as imaged rather than to a folio citation.
He was sceptical of the American drug that Europe was actually buying. The cited study reports his verdict on guaiacum, the palo de las Indias then sold across Europe as the cure for the pox: "I believe diet cures more than the Wood of the Indies." He recommended mercury with theriac, sarsaparilla water, and mercury with sarsaparilla, and attributed the severity of the disease in the Indies to heat, humidity and the patient's own conduct and temperament - humoral reasoning adapted to a new place, not abandoned.
The surgery is in the book too, described in the first person. Folio 123, in the section "De cabeça", treats a head wound in which the medullary substance was rising and coming level with the cranium: he records treating it with an emplaster of egg yolks, oil of camomile and linseed and flowers of camomile as a mitigant against the apostema of the pericranium, and with lentil flour laid on a small silk patten so that its weight compressed the swelling, continuing until the wound would cicatrise. What the leaf establishes is the practice and the language, not the outcome.
The cited authors put firm limits on what he achieved, and they are part of the honest case for him. He was a surgeon in a hierarchy that placed surgeons beneath university-trained physicians and, in their words, "lacked the theoretical tools to effectively contest the dogmatic principles upheld by university-trained physicians", so he argued by anecdote - the newly arrived doctor who ate anything and died of his own theory, the physicians fooled by urine reddened by prickly pear. His book was far less read than Francisco Hernández's cataloguing or Monardes's histories, and the authors decline to call him a precursor of the Scientific Revolution, concluding only that he was among the first surgeons whose practical experience in the New World challenged scholastic principles.
The crediting and the extraction are the same act, and the title page says so without embarrassment: the manner in which the Indians cure is offered as "muy vtil y prouechoso para en España". Knowledge taken from Nahua practice is named as such, then valued by what it is worth to the metropolis - and by his own account on folio 40 the author withheld his best American remedy from colleagues rather than publishing it in New Spain. Crediting a source and appropriating it were not alternatives here.