SCIENCE AND WAR 221 



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 pebrine 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 Cevennes were abandoned and the 

 whole region was desolate. Pasteur, at the instiga- 

 tion 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 conclu- 

 sion. Pebrine, due to " corpuscles " readily detected 

 under the microscope, could be recognized at the mo- 

 ment 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 infini- 

 tesiinally small as disorganizes 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." 



Returning in July, 1870, from a visit to Liebig 

 at Munich, Pasteur heard at Strasburg of the im- 

 minence of war. All his dreams of conquest over 

 disease and death seemed to vanish. He hurried to 

 Paris. His son, eighteen years of age, set out with 



