Pasteur's attention was next directed to the wine industry, which then had an annual value to France of 500,000,000 francs. Might not the acidity, bitterness, defective flavor, which were threatening the foreign sale of French wines, be owing to ferments? He discovered that this was, indeed, the case, and that the diseases of wine could be cured by the simple expedient of heating the liquor for a few moments to a temperature of 50° to 60° C. Tests on a considerable scale were made by order of the naval authorities. The ship Jean Bart before starting on a voyage took on board five hundred liters of wine, half of which had been heated under Pasteur's directions. At the end of ten months the _pasteurized_ wine was mellow and of good color, while the wine which had not been heated had an astringent, almost bitter, taste. A more extensive test--seven hundred hectoliters, of which six hundred and fifty had been pasteurized--was carried out on the frigate la Sibylle with satisfactory results. Previously wines had been preserved by the addition of alcohol, which made them both dearer and more detrimental to health. In 1865 Pasteur was called upon to exercise his scientific acumen on behalf of the silk industry. A disease--_pébrine_--had appeared among silkworms in 1845. In 1849 the effect on the French industry was disastrous. In the single _arrondissement_ of Alais an annual income of 120,000,000 francs was lost for the subsequent fifteen years. The mulberry plantations of the Cévennes were abandoned and the whole region was desolate. Pasteur, at the instigation of the Minister of Agriculture, undertook an investigation. After four or five years, in spite of repeated domestic afflictions and the breakdown of his own health, he arrived at a successful conclusion. _Pébrine_, due to "corpuscles" readily detected under the microscope, could be recognized at the moment of the moth's formation. A second disease, _flacherie_, was due to a micro-organism found in the digestive cavity of the moth. Measures were taken to select the seed of the healthy moths and to destroy the others. These investigations revealed the infinitesimally small as disorganizers of living tissue, and brought Pasteur nearer his purpose "of arriving," as he had expressed it to Napoleon III in 1863, "at the knowledge of the causes of putrid and contagious diseases."