It was because he was the only university teacher in Avignon to occupy himself with entomology that Pasteur visited him in 1865. The illustrious chemist had been striving to check the plague that was devastating the silkworm nurseries, and as he knew nothing of the subject which he proposed to study, not even understanding the constitution of the cocoon or the evolution of the silkworm, he sought out Fabre in order to obtain from his store of entomological wisdom the elementary ideas which he would find indispensable. Fabre has told us, in a moving page (4/20), with what a total lack of comprehension of "poverty in a black coat" the great scientist gazed at his poor home. Preoccupied by another problem, that of the amelioration of wines by means of heat, Pasteur asked him point-blank-- him, the humble proletarian of the university caste, who drank only the cheapest wine of the country--to show him his cellar. "My cellar! Why not my vaults, my dusty bottles, labelled according to age and vintage! But Pasteur insisted. Then, pointing with my finger, I showed him, in a corner of the kitchen, a chair with all the straw gone, and on this chair a two- gallon demijohn: 'There is my cave, monsieur!'" If the country professor was embarrassed by the chilliness of the other, he was none the less shocked by his attitude. It would seem, from what Fabre has said, that Pasteur treated him with a hauteur which was slightly disdainful. The ignorant genius questioned his humble colleague, distantly giving him his orders, explaining his plans and his ideas, and informing him in what directions he required assistance. After this, we cannot be surprised if the naturalist was silent. How could sympathetic relations have survived this first meeting? Fabre could not forgive it. His own character was too independent to accommodate itself to Pasteur's. Yet never, perhaps, were two men made for a better understanding. They were equally expert in exercising their admirable powers of vision in the vast field of nature, equally critical of self, equally careful never to depart from the strict limits of the facts; and they were, one may say, equally eminent in the domain of invention, different though their fortunes may have been; for the sublimity of scientific discoveries, however full of genius they may be, is often measured only by the immediate consequences drawn therefrom and the practical importance of their results. In reality, were they not two rivals, worthy of being placed side by side in the paradise of sages? Both of them, the one by demolishing the theory of spontaneous generation, the other by refuting the mechanical theory of the origin of instincts, have brought into due prominence the great unknown and mysterious forces which seem destined to hold eternally in suspense the profound enigma of life.