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which they were put upon the market. Alterations were constantly taking place in these articles, due, it was supposed, to certain "diseases." Inasmuch as these wares represented a large share of the wealth of France, Pasteur was urged to investigate this matter. He commenced this research in 1864.

The ensuing year, an outbreak of cholera called his attention to that disease, and he studied it with a view to finding a bacterial cause for it, but without result. In the meantime, he was investigating a pestilence of silk worms which was proving so destructive as to threaten the silk industries of southern Europe with extinction. He was quite successful with this, and was quickly able to devise a method of combating it.

Doubtless the strain incident to the many and great investigations being simultaneously pushed by him during the three years, 1865 to 3868, was responsible for a series of paralytic shocks, the first of which struck him October 10, 1868. "While thought to be hopelessly ill and incapable of rational thinking, he insisted upon dictating a method of dealing with flacherie, a second silkworm disease which had been discovered by him in the course of his research on the silkworm pestilence. His treatment for flacherie proved to be a complete success, also. He recovered from this attack, but was physically lamed for the rest of his life. Although crippled in body, the work accomplished by him during his remaining twenty-seven years was not only stupendous in amount, but of transcending importance to mankind. I doubt if the example afforded by the heroic labors of the paralyzed Pasteur can be matched from the annals of all time.

By the close of 1871, he had shown that the "diseases" of wines and beers were caused by certain bacteria, all of which might be killed without injury to the product by heating it for a few minutes at a temperature of 50°-60° C.; and that if hermetically sealed at this temperature the liquors might be preserved perfectly for an indefinite period.

These studies had now thoroughly convinced their author that all diseases are of bacterial origin—a conception, you will recall, which had first come into his mind by a flash of genius ten years before. Indeed, four years prior to this (1867), Pasteur's researches had convinced a British surgeon, Joseph Lister, of Edinburgh, of the microbic origin of those purulent infections which accompany wounds and surgical operations. And although himself unacquainted with bacteriology, he successfully devised the method of asepsis which has made his name a household word.

Before the close of 1873, Pasteur finished the solution of that great problem begun at Lille nineteen years before—the mystery of fermentation. It is this: Certain bacteria, living at the surface of sugary fluids cause no fermentation, because they secure the oxygen which they need