i 4 THE POPULAR SCIENCE MONTHLY 



which they were put upon the market. Alterations were constantly 

 taking place in these articles, due, it was supposed, to certain " dis- 

 eases." 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 success- 

 ful 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 flaclierie, a second silkworm disease which had been dis- 

 covered 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 tem- 

 perature of 50°-60° C. ; and that if hermetically sealed at this tem- 

 perature 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. In- 

 deed, four years prior to this (1867), Pasteur's researches had con- 

 vinced a British surgeon, Joseph Lister, of Edinburgh, of the microbic 

 origin of those purulent infections which accompany wounds and surg- 

 ical 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 fermenta- 

 tion. It is this : Certain bacteria, living at the surface of sugary fluids 

 cause no fermentation, because they secure the oxygen which they need 



