Pasteur’s tour through the district of Avignon was in connection with sericulture. For some years the silk-worm nurseries had been at sixes and sevens, ravaged by unknown plagues. The silkworms, without appreciable cause, became masses of putrid deliquescence, or hardened into stony lumps. The peasant, in dismay, saw one of his chief sources of income disappearing; after much expense and trouble he had to throw his litters on the dung-heap. A few words were exchanged concerning the prevailing evil; then, without further preamble: “I wanted to see some cocoons,” said my visitor; “I have never seen any; I know them only by name. Could you get me some?” “Nothing simpler. My landlord is himself a dealer in cocoons, and he lives across the road. If you’ll be good enough to wait a moment, I will bring you what you want.” A few long strides and I had reached my neighbour’s house, where I stuffed my pockets with cocoons. On my return I offered them to the scientist. He took one, turned it over and over in his fingers; curiously he examined it, as we should some singular object which had come from the other end of the world. He shook it against his ear. “It rattles!” he said, quite surprised. “There is something inside!” “Why, yes!” “But what?” “The chrysalis.” “What’s that, the chrysalis?” “I mean the sort of mummy into which the caterpillar turns before it becomes a moth.” “And in every cocoon there is one of those things?” “Of course; it’s to protect the chrysalis that the caterpillar spins.” “Ah!” And without more ado, the cocoons went into the pocket of the scientist, who was to inform himself at leisure concerning this great novelty, the chrysalis. This magnificent assurance impressed me. Knowing nothing of caterpillar, cocoon, chrysalis, or metamorphosis, Pasteur had come to regenerate the silkworm. The ancient gymnasts presented themselves naked for the contest. This ingenious thinker, who was to fight the plague of the silk-worm nurseries, had also hastened to battle wholly naked: that is, devoid of the simplest notions of the insect he was to save from danger. I was astounded; more, I was filled with wonder. [69] The fact is indeed so extraordinary that it may well appear incredible, but it receives authentic confirmation from the wholly concordant account of Duclaux, Pasteur’s pupil and historiographer, as well as from the honesty of the naturalist, who is assuredly incapable of having invented the story for our amusement. I still remember the day [says Duclaux] when Pasteur, returning to the laboratory, said to me with a touch of excitement in his voice: “Do you know what M. Dumas has just asked of me? To go to the Midi, to study the silk-worm disease.”