When Pasteur recovered sufficiently to resume work, it was soon clear to apprehensive friends that he had no intention of leaving his ideas to be worked out by other men. The miseries of the Franco-Prussian War deeply affected him, and could not fail to inhibit his productiveness, but after a time the unquenchable love for experimental research was once more ascendant and there began a new epoch, the epoch of great discoveries relating to the origin and cure or prevention of the infectious diseases of man and the domestic animals. As in the case of Ignatius Loyola, it seems as if the lamp of the genius shone with a larger and more luminous flame after the onset of bodily infirmity in defiance of the physical mechanism which is too often permitted to master the will. After his illness Pasteur devoted himself even more than before to the study of the various biological problems connected with human diseases. There was one exception to this, in his series of studies on beer, undertaken shortly after {313} the Franco-Prussian War. Pasteur was an ardent patriot, so much so, indeed, that after the war he sent back to the German government certain decorations and diplomas that had been conferred upon him. He thought that his country had been overreached by a scheming, political statesman, bent on the aggrandizement of the kingdom of Prussia. To the end of his life this feeling of hostility never entirely vanished. It was his hope, then, that by improving the character of French beer it might not only be made more wholesome in the best sense of the word, but also that the French brewing industry might be made a serious rival of its German competitors. Pasteur's discoveries are the most important for the brewing industry that have ever been made. The Germans proved, however, even more capable of taking advantage of them than his French compatriots. After this Pasteur devoted himself without further interruption to the study of the microbic diseases of man. His greatest practical triumph was undoubtedly with regard to hydrophobia, or, as it is more properly called, rabies. The mystery of the disease was most illusive. Pasteur could not succeed in finding the germ of the disease. Even down to our own day it has not been satisfactorily demonstrated. In spite of this lack of an important element of knowledge, which might be supposed absolutely essential for the successful therapeutics of rabies from a biological standpoint, Pasteur succeeded in producing material that would protect those bitten by rabid dogs from developing the affection.