This observation may be illustrated by the literary history of Lenglet du Fresnoy. He opened his career by addressing a letter and a tract to the Sorbonne, on the extraordinary affair of Maria d'Agreda, abbess of the nunnery of the Immaculate Conception in Spain, whose mystical Life of the Virgin, published on the decease of the abbess, and which was received with such rapture in Spain, had just appeared at Paris, where it excited the murmurs of the pious, and the inquiries of the curious. This mystical Life was declared to be founded on apparitions and revelations experienced by the abbess. Lenglet proved, or asserted, that the abbess was not the writer of this pretended Life, though the manuscript existed in her handwriting; and secondly, that the apparitions and revelations recorded were against all the rules of apparitions and revelations which he had painfully discovered. The affair was of a delicate nature. The writer was young and incredulous; a grey-beard, more deeply versed in theology, replied, and the Sorbonnists silenced our philosopher in embryo. Lenglet confined these researches to his portfolio; and so long a period as fifty-five years had elapsed before they saw the light. It was when Calmet published his Dissertations on Apparitions, that the subject provoked Lenglet to return to his forsaken researches. He now published all he had formerly composed on the affair of Maria d'Agreda, and two other works; the one, "_Traite historique et dogmatique sur les Apparitions, les Visions, et les Revelations particulieres_," in two volumes; and "_Recueil de Dissertations anciennes et nouvelles, sur les Apparitions, &c._," with a catalogue of authors on this subject, in four volumes. When he edited the _Roman de la Rose_, in compiling the glossary of this ancient poem, it led him to reprint many of the earliest French poets; to give an enlarged edition of the _Arrets d'Amour_, that work of love and chivalry, in which his fancy was now so deeply embedded; while the subject of Romance itself naturally led to the taste of romantic productions which appeared in "_L'Usage des Romans_," and its accompanying copious nomenclature of all romances and romance-writers, ancient and modern. Our vivacious Abbe had been bewildered by his delight in the works of a chemical philosopher; and though he did not believe in the existence of apparitions, and certainly was more than a sceptic in history, yet it is certain that the "grande oeuvre" was an article in his creed; it would have ruined him in experiments, if he had been rich enough to have been ruined. It altered his health; and the most important result of his chemical studies appears to have been the invention of a syrup, in which he had great confidence; but its trial blew him up into a tympany, from which he was only relieved by having recourse to a drug, also of his own discovery, which, in counteracting the syrup, reduced him to an alarming state of atrophy.