from the air. They are aerobic. But if sunk, by accident or otherwise, beneath the surface they must either perish or adapt themselves to their new environment by extracting oxygen from the nearest source of supply. This is the sugar of the solution. They are able to accomplish this but slowly at first, and the bulk of the first submerged bacteria suffocate. But reproducing rapidly by budding, ensuing generations are gradually but, for us, rapidly converted into true anaerobes, which, robbing the sugar molecules of oxygen, cause that chemical change called fermentation.
This problem solved, Pasteur was able to show from it the following results of his work: (1) Precisely what fermentation is, (2) that ferments are living organisms, (3) that every variety of fermentation is caused by a special ferment, (4) that neither bacteria nor any other life forms are spontaneously generated, (5) how to prepare culture media suitable to the growth of various bacteria, (6) how to propagate pure cultures of bacteria, (7) a basis of classification of bacteria, (8) the chemical and microscopical technique of bacteriology, (9) the cause and cure of various "diseases" of fermented liquors, (10) the cause and cure of various silkworm diseases, (11) an explanation of the mystery of the optical behavior of tartaric and racemic acids, (12) two new tartaric acids (13) how to synthesize meso-tartaric and racemic acids, (14) how to make racemic acid available to commerce.
In comparison with this great work of Pasteur's, the classic example of persevering genius—Newton's fourteen-year pondering over falling bodies—sinks into insignificance, no matter how considered, either as to time involved, the difficulties encountered, or the practical value of results obtained. Nor must one fail to note that incidentally Pasteur had beaten out a road into a new world and created two new sciences which were to serve as vehicles for its exploration and exploitation.
Pasteur's health had been so impaired by these arduous researches that he was now compelled to give up his professorship. As he was entirely without private resources, his colleagues exerted themselves upon his behalf, and succeeded in obtaining for him from the government, in 1874, an annual pension of 12,000 francs, the equivalent of the salary he had previously received.
His friends now urged him to abstain from work; but his genius could not endure inaction. He began the study of anthrax and feruncular diseases. While these studies were in progress, the bubonic plague appeared in Russia, and the yellow fever began to work havoc in the French colonies on the west coast of Africa and in the United States. Pasteur prepared a program of preliminary researches upon them. A paper to the Académie des Sciences presented December 30, 1878, closes with these words: "Is it not permissible to believe that a day will come when easily applied preventative means will arrest those scourges which suddenly desolate and terrify populations."
