DISEASES OF SILKWORMS 47 



spots, like pepper, which came on infected worms. 

 Tons of all sorts of remedies disinfection, fumiga- 

 tion, and so forth had been tried, in vain, season 

 after season. Things looked utterly hopeless. 

 Sometimes the worms would sicken early, some- 

 times they would sicken late ; sometimes they 

 would seem healthy right up to the period of spin- 

 ning, yet the moths would be unhealthy, and the 

 disease would recur in the next year's worms. 

 Theories of the disease were to be had in any 

 number. One or two microscopists had found, in 

 the worm or in the moth, certain oval "corpuscles": 

 but had stopped there, making nothing of them. 



On June 6, 1865, Pasteur started for Alais, a 

 hot-bed of the disease. By incessant questioning, 

 he was able to measure the bewilderment of the 

 proprietors : they had tried everything, thought of 

 everything, accomplished nothing. He set himself 

 to find out the meaning of the corpuscles. At 

 once, he was in the thick of perplexities. He had 

 under examination two lots of worms : we may 

 call them A and B. Both were raised from 

 Japanese seed : lot A was from seed officially 

 guaranteed: lot B was not guaranteed. Lot A 

 spun well : lot B languished. But he found only 

 a few corpuscles in lot B : and he found many in 

 the chrysalids and moths of lot A. He waited till 

 lot B had spun : and he found that the chrysalids 



