THE DISEASES OF SILK WORMS 127 



of cocoons. Pasteur took one and turned it around 

 and around in his fingers as he attentively exam- 

 ined the unfamiliar object. Shaking it before his 

 ear he exclaimed in surprise: 



"It rattles; there is something inside of it!" 



"Yes, certainly," said Fabre. 



"But what is it?" 



"The chrysalis." 



"The chrysalis! What is that?" 



"I might say it is a sort of mummy into which 

 the caterpillar transforms before becoming a moth." 



"Is there one of these things in every cocoon?" 



"Certainly. It is to protect the chrysalis that 

 the caterpillar spins." 



"Ah!" 



It is somewhat curious to find this celebrated 

 man of science ignorant of simple facts of natural 

 history which children usually learn in the gram- 

 mar school. If there are any advantages in 

 attacking a problem in entire ignorance of what 

 has been previously done upon it Pasteur certainly 

 possessed them. But he possessed what was in- 

 finitely more valuable than information and that is 

 a fertile and resourceful mind trained in the 

 methods of experimental investigation and endowed 



