At last Gernez went off to the north to study the silk worms of Valenciennes, and Pasteur, not clearly knowing the reason why, wrote to him and asked him to do that feeding experiment up there. Gernez had some nice broods of healthy worms. Gernez was sure in his own head--no matter what his chief might think--that the wee globules were really living things, parasites, assassins of the silkworm. He took forty healthy worms and fed them on good healthy mulberry leaves that had never been fed on by sick beasts. These worms proceeded to spin twenty-seven good cocoons and there were no globules in the moths that came from them. He smeared some other leaves with crushed-up sick moths and fed them to some day-old worms--and these worms wasted away to a slow death, they became covered with pepper spots and their bodies swarmed with the sub-visible globules. He took some more leaves with crushed-up sick moths and fed these to some old worms just ready to spin cocoons; the worms lived to spin the cocoons, but the moths that came out of the cocoons were loaded with the globules, and the worms from their eggs came to nothing. Gernez was excited--and he became more excited when still nights at his microscope showed him that the globules increased tremendously as the worms faded to their deaths.... Gernez hurried to Pasteur. “It is solved,” he cried, “the little globules are alive--they are _parasites_!--They are what make the worms sick!” It was six months before Pasteur was convinced that Gernez was right, but when at last he understood, he swooped back on his work, and once more called the Committee together. “The little corpuscles are not only a sign of the disease, they are its cause. These globules are alive, they multiply, they force themselves into every part of the moth’s body. Where we made our mistake was to examine only a little part of the moth, we only looked under the skin of the moth’s belly--we’ve got to grind up the whole beast and examine all of it. Then if we do not find the globules we can safely use the eggs for next year’s worms!” The committee tried the new scheme and it worked--the next year they had fine worms that gave them splendid yields of silk.