146 LOUIS PASTEUR 



duction of cocoons was concerned. It was proved 

 that almost invariably the following year the eggs of 

 these fine-looking groups were unproductive. Num- 

 bers of the agricultural boards, and practitioners, not 

 being able to believe in the existence of the disease in 

 collections that were so satisfactory as regards the 

 abundance and beauty of the cocoons, persisted in 

 thinking that the failures had an origin not connected 

 with the seed itself. This resulted in deception after 

 deception, often even in mistakes that were much to 

 be regretted. Frequently the best husbandmen were 

 known to reserve for the production of eggs some 

 very fine cultivations, not having observed in the 

 worms either spots of pebrine or corpuscles even up 

 to the time when the mounting of the. brambles had 

 been accomplished; and the year following they had 

 the pain of seeing all the cultivations from these eggs 

 perish. These circumstances, so well calculated to 

 produce discouragement and to give the disease a 

 mysterious character, met with their natural explana- 

 tion in the facts proved by experimental infection. 



Still, as it never occurs to the cultivator to infect 

 the worms directly by giving them, food charged with 

 corpusculous debris, it might be asked how, in the 

 industrial establishments, such results can be pro- 

 duced. Pasteur lost no time in solving this difficulty. 



In a cultivation containing corpusculous worms 

 these worms perpetually furnish contagious matter, 



