The medical cultures of New Spain are the result of a particular confluence of discourses. These discourses could, in theory, be mutually illuminating; in practice, the contact of medical cultures sometimes led to confusion and misunderstanding.2 Whether through mutual comprehension or misinterpretation, however, the meetings of medical cultures almost always created something new: hybrid or mestizo medical knowledge and therapeutic practices.3 Texts that give us a good sense of the wide variety of beliefs about disease-for example, how diseases were spread and might be prevented-are quite rare. That is why the Relaciones Geográficas de Indias-alluded to in the preceding chapter by Morales and examined in greater detail here-are so exciting. The Relaciones Geográficas (henceforth RGs) are a corpus of texts generated in New Spain during the second half of the sixteenth century, and they provide a nearly unique glimpse of a cross-section of the society of the period. The RGs not only cause us to reconsider our estimates of the number of medical cultures at work, but also they demand we reexamine our understanding of the hierarchy of medical cultures, as we shall see. But first it will be helpful to get a better understanding of the RGs and their characteristics.