1865—1870 139 



worms, he liked to see what was going on in neighbouring 

 magnaneries. A neighbour in the Pont Gisquet, a cultivator 

 of the name of Cardinal, had raised with great success a brood 

 originating from the famous Japanese seed. He was disap- 

 pointed, however, in the eggs produced by the moths, and 

 Pasteur's microscope revealed the fact that those moths were 

 all corpuscled, in spite of their healthy origin. Pasteur did 

 not suspect that origin, for the worms had shown health and 

 vigour through all their stages of growth, and seemed to have 

 issued from healthy parents. But Cardinal had raised another 

 brood, the produce of unsound seed, immediately above these 

 healthy worms. The excreta from this second brood could 

 fall on to the frames of those below them, and the healthy 

 worms had become contaminated. Pasteur demonstrated that 

 the pebrine contagion might take place in one or two different 

 ways : either from direct contact between the worms on the 

 same frame, or by the soiling of the food from the very in- 

 fectious excreta. The remedy for the pebrine seemed now 

 found. "The corpuscle disease," said Pasteur, "is as easily 

 avoided as it is easily contracted." But when he thought he 

 had reached his goal a sudden difficulty rose in his way. Out 

 of sixteen broods of worms which he had raised, and which 

 presented an excellent appearance, the sixteenth perished 

 almost entirely immediately after the first moulting. "In a 

 brood of a hundred worms," wrote Pasteur, " I picked up fifteen 

 or twenty dead ones every day, black and rotting with extra- 

 ordinary rapidity. . . . They were soft and flaccid like an 

 empty bladder. I looked in vain for corpuscles ; there was not 

 a trace of them." 



Pasteur was temporarily troubled and discouraged. But he 

 consulted the writings of former students of silkworm diseases, 

 and, when he discovered vibriones in those dead worms, he 

 did not doubt that he had under his eyes a well characterized 

 example of the flachery disease — a disease independent and 

 distinct from the pebrine. He wrote to Duruy, and acquainted 

 him with the results he had obtained and the obstacles he 

 encountered. Duruy wrote back on April 9, 1867 — 



' Thank you for your letter and the good news it contains. 

 'Not very far from you, at Avignon, a statue has been 

 erected to the Persian who imported into France the culti- 

 vation of madder ; what then will not be done for the rescuer 

 of two of our greatest industries ! Do not forget to inform me 



