Page:Great Men and Famous Women Volume 6.djvu/224

380 WORKMEN AND HEROES 4 Before this, however, he had examined the claims of Pouchet and others to their alleged discovery of spontaneous generation ; in other words, the produc- tion of life. Ranging himself against them, Pasteur showed their experiments not to have been conclusive, simply because they had not succeeded in excluding the dust which contained germs of life in the shape of spores of microscopic plants. The "diseases" of wine produce sour wine, wine that "spirits," "greasy" wine, and bitter wine. Pasteur found each to be due to a different microscopic ferment, all of which could be killed by heat. He placed bottles of wine in a bath heated to 60 C, and invited the most experienced wine tasters of Paris to try them afterward. The result of the test was the unanimous verdict that the wines had not been injured in the least, and to-day these " diseases " of wine are a thing of the past. There are departments in France where the culture of the silk-worm is the principal industry of the inhabitants. In 1849 a strange disease, called pebrine, broke out among the worms ; they were unable to moult and died before the cocoons were spun. It spread in the most alarming manner until, from a crop with an average of one hundred and thirty million francs a year, the production of silk went to less than fifty millions. The silk cultivators sent for eggs seed is the technical name to Italy and Greece, and for one season all went well. The next, the plague was as bad as ever. More than that, it spread to Italy, Spain, Greece, and Turkey, until Japan was the only silk-producing country where the worm was healthy. Societies and governments, as well as individuals, were aghast, for the silk industry of the world was on the verge of annihilation, and every remedy the mind of man could conceive was tried, only to be rejected. In France alone the loss in 1865 was over one hundred million francs. At the suggestion of Professor Dumas, the Government induced Pasteur to examine into the " disease." He had seen in a report on the epidemic made by M. de Quatrefages, that there were found in the diseased worms certain minute corpuscles only t'o be seen under the microscope. When in June, 1865, Pasteur arrived in the town of Alais, he found these corpuscles without difficulty. He traced them from the worm to the chrysalid, in the cocoon, and thence to the moth ; he found worms hatched from the eggs laid by these moths invariably de- veloped the corpuscles. He crushed a corpuscular moth in water, painted a mul- berry leaf with it, fed it to a healthy worm, and the corpuscles developed. He hatched eggs from moths free from corpuscles and secured healthy worms. While working on the " disease," Pasteur discovered in 1867 that the mortality among the worms was in part due to another disease, the flacherie, and this he found was the result of imperfect digestion. Flacherie was contagious, and was caused by the fermentation of the food eaten in the body of the worm. The causes of this fermentation, the condition of the leaves, the temperature, and others were pointed out. , As the result of five years' work, Pasteur had restored the silk industry to its former position, and had shown that the microscopic examination of the moth laying the eggs to be hatched was a perfect safeguard against pebrine and flacherie.