Problemas y secretos maravillosos de las Indias (Mexico, 1591)

A physician's book of questions about America, printed at Mexico in 1591 and written before its author was thirty. It asks why the Indies shake, why quicksilver is lost in the silver works, what chocolate and tobacco do to the body, and whether people born in the Indies differ from people born in Europe — answering the ancient doctrine that the torrid zone was uninhabitable with an argument from altitude, rainfall and snow.