Eugenio Espejo, Reflexiones acerca de las viruelas (Quito, 1785)
A Quito physician's argument, first printed in 1785, that a town can be preserved from smallpox by deliberate inoculation, and that doing so is a patriotic and a Christian act rather than a presumption against providence. The Spanish physician Francisco Gil, whose own dissertation on the same problem had appeared the year before, printed Espejo's text as an appendix to his second edition.
Why this wins its question: The standard telling of smallpox in Spanish America starts at Jenner in 1796 and jumps to the Balmis expedition of 1803, which leaves out the twenty years in which the argument was actually had - and had partly by American writers. Espejo is the clearest case: a Quito author whose 1785 text a Madrid physician thought worth binding into his own second edition, arguing against an official Spanish tribunal that called the practice dangerous. This object states the disagreement between Espejo and Gil rather than merging them, records the Protomedicato's opposition as its own claim, and marks where its two sources contradict each other over Narino instead of choosing a side silently. Its main limitation is stated too: the scholarly literature reachable here treats the 1785 Quito printing only in passing, so the bibliographic claims are carried below 0.85.
Claims
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Espejo's Reflexiones acerca de las viruelas appeared in a first edition at Quito in 1785, fourteen years before Jenner's vaccine reached the Spanish empire and while the question at issue was still inoculation with smallpox itself.
Espejo's case for inoculation is civic rather than merely clinical - he presents it as a patriotic act directed at the conservation and propagation of the human race, so that the inhabitants of a nation come through unharmed.
He met the religious objection head on, arguing that inoculating was a Christian proceeding. That the argument had to be made at all indicates the shape of the opposition he was answering.
The Spanish physician Francisco Gil had published in 1784 a Disertacion fisico-medica prescribing a sure method to preserve the towns from smallpox until its complete extinction throughout the kingdom - a stated goal of eradication, not of treatment.
Gil's debt to Espejo was large enough that he inserted the Quito author's work as an appendix to the second edition of his own book - a metropolitan Spanish physician reprinting an American colonial writer inside his own treatise.
Gil and Espejo did not agree. Gil argued for inoculation carried out with measure and prudence, enumerated its risks at length, promoted Robert Sutton's refined English technique of minimal scarification, and wanted the practice confined to state hospitals on the outskirts of cities - a narrower proposal than Espejo's.
Spanish medical officialdom was against them. The Real Tribunal del Protomedicato regarded inoculation as an ineffective and dangerous method, on religious grounds alongside medical ones. The institutions of the empire held both positions at once, and the argument for inoculation was a minority one inside them.
In New Granada the same problem was being worked on through epidemics in 1782, 1783, 1785 and 1801, with Jose Celestino Mutis promoting preventive measures, and it was resolved by the state rather than by any individual - Josep Salvany, second in command of the Royal Vaccine Expedition, reached Santafe de Bogota on 17 December 1804 carrying the vaccine in two children.
A contested case sits beside Espejo's. Antonio Narino wrote to the viceroy on 30 July 1802 claiming that after 47 days of work he could present a boy in whom a pustule had taken with every appearance of true vaccine. Moreno and Moreno treat this as a product of his reading; Vanegas holds it highly improbable that a vaccine could have been created in Narino's prison conditions without access to bovine lymph, and concludes he most likely mistook an unrelated lesion for a success.