He carried his scruples so far as to give up his chemistry professorship at the School of Fine Arts, where he had been lecturing since 1863. He had endeavoured in his lessons to draw the attention of his artist pupils, who came from so many distant places, to the actual principles of Science. “Let us always make application our object,” he said, “but resting on the stern and solid basis of scientific principles. Without those principles, application is nothing more than a series of recipes and constitutes what is called routine. Progress with routine is possible, but desperately slow.” Another reason prevented him from accepting the post offered him at the Ecole Normale; this was that the tiny pavilion which he had made his laboratory was much too small and too inconvenient to accommodate the pupils he would have to teach. The only suitable laboratory at the Ecole was that of his friend, Henri Sainte Claire Deville, and Pasteur was reluctant to invade it. He had a great affection for his brilliant colleague, who was indeed a particularly charming man, still youthful in spite of his forty-nine summers, active, energetic, witty. “I have no wit,” Pasteur would say quite simply. Deville was a great contrast to his two great friends, Pasteur and Claude Bernard, with their grave meditative manner. He enjoyed boarding at the Ecole and having his meals at the students’ table, where his gaiety brightened and amused everybody, effacing the distance between masters and pupils and yet never losing by this familiar attitude a particle of the respect he inspired. Sometimes, however, when preoccupied with the heavy expenses of his laboratory, he would invite himself to lunch with Duruy, from whom--as from the Emperor or any one else--he usually succeeded in coaxing what he wanted. The general state of things connected with higher education was at that time most deplorable. The Sorbonne was as Richelieu had left it--the Museum was sadly inadequate. At the Collège de France, it was indeed impossible to call by the name of laboratory the narrow, damp and unhealthy cellars, which Claude Bernard called “scientists’ graves,” and where he had contracted the long illness from which he was only just recovering. Duruy understood and deplored this penury, but his voice was scarcely heard in cabinet councils, the other Ministers being absorbed in politics. Pasteur, whose self-effacing modesty disappeared when the interests of science were in question, presented to Napoleon, through the medium of his enlightened aide de camp, General Favé, the following letter, a most interesting one, for, in it, possibilities of future discoveries are hinted at, which later became accomplished facts.