At Avignon Fabre was instructed to give his personal services. He gave them with all his heart; and it was then that he undertook, in the ancient Abbey of Saint-Martial, those famous free lectures which have remained celebrated in the memory of that generation. There, under the ancient Gothic vault, among the pupils of the primary Normal College, an eager crowd of listeners pressed to hear him; and among the most assiduous was Roumanille, the friend of Mistral, he who so exquisitely wove into his harmonies "the laughter of young maidens and the flowers of springtime." No one expounded a fact better than Fabre; no one explained it so fully and so clearly. No one could teach as he did, in a fashion so simple, so animated, so picturesque, and by methods so original. He was indeed convinced that even in early childhood it was possible for both boys and girls to learn and to love many subjects which had hitherto never been proposed; and in particular that Natural History which to him was a book in which all the world might read, but that university methods had reduced it to a tedious and useless study in which the letter "killed the life." He knew the secret of communicating his conviction, his profound faith, to his hearers: that sacred fire which animated him, that passion for all the creatures of nature. These lectures took place in the evening, twice a week, alternately with the municipal lectures, to which Fabre brought no less application and ardour. In the intention of those who instituted them these latter were above all to be practical and scientific, dealing with science applied to agriculture, the arts, and industry. But might he not also expect auditors of another quality, in love only with the ideal, "who, without troubling about the possible applications of scientific theory, desired above all to be initiated into the action of the forces which rule nature, and thereby to open to their minds more wondrous horizons"? Such were the noble scruples which troubled his conscience, and which appeared in the letter which he addressed to the administration of the city, when he was entrusted by the latter with what he regarded as a lofty and most important mission. "...Is it to be understood that every purely scientific aspect, incapable of immediate application, is to be rigorously banished from these lessons? Is it to be understood that, confined to an impassable circle, the value of every truth must be reckoned at so much per hundred, and that I must silently pass over all that aims only at satisfying a laudable desire of knowledge? No, gentlemen, for then these lectures would lack a very essential thing: the spirit which gives life!" (4/26.)