In a Spain that was still emerging from the rigid orthodoxy of the Counter Reformation, the slightest quarter given to scientific empiricism was considered a materialist threat. Among the few Spaniards who did study the new scientific trends of the Enlightenment in the first half of the eighteenth century were Jesuit teachers. Their Seminary of Nobles at Madrid was for all purposes gloriosa Universidad de las Hespafias, since its Aulas en donde con novedad se ensefiaban las Ciencias contrasted so sharply with the grave ignorancia, poca ciencia y mucho vicio of the old Spanish universities.' Father Jos6 Francisco de Isla, famous Jesuit satirist of pulpiteers, solo daba algun quartel a la Phjrsica experimental,2 but his acceptance of certain materialist ideas had a profound influence on his novelistic technique. Locke's sensualist empiricism is the critical point of view in Isla's early satires against Galenic medicine. Doctor Martin Martinez, a modern physician and associate of Feij6o, creerd a sus sentidos, siempre que no hay raz6n evidente para la duda.3 Enlightened clerics like Isla permitted themselves rather unlimited freedom in negative scientific criticism of superstition and stupidity, whereas they feared the positive criticism that por las ciencias naturales se havia atrevido a escalar hasta el Sagrado Alcazar de la Religi6n (I, 110). But Isla's religious fortress was as vulnerable to sedition as to storming from without. If his indulgence in the putrescent details of Fray Gerundio's family life is reminiscent of the French naturalists, his technique in creating characters is still more similar to theirs. It was no creer a