Pasteur appreciated the pretty legend, but was more interested in the history of the acclimatizing of the mulberry tree. From Provence Louis XI took it to Touraine: Catherine de Medici planted it in Orléanais. Henry IV had some mulberry trees planted in the park at Fontainebleau and in the Tuileries where they succeeded admirably. He also encouraged a _Treatise on the Gathering of Silk_ by Olivier de Serres. This earliest agricultural writer in France was much appreciated by the king, in spite of the opposition of Sully, who did not believe in this new fortune for France. Documentary evidence is lacking as to the development of the silk industry. From 1700 to 1788, wrote Quatrefages, France produced annually about 6,000,000 kilogrammes of cocoons. This was decreased by one-half under the Republic; wool replaced silk perhaps from necessity, perhaps from affectation. Napoleon I restored that luxury. The sericicultural industry prospered from the Imperial Epoch until the reign of Louis Philippe, to such an extent as to reach in one year a total of 20,000,000 kilogrammes of cocoons, representing 100,000,000 francs. The name of Tree of Gold given to the mulberry, had never been better deserved. Suddenly all these riches fell away. A mysterious disease was destroying the nurseries. “Eggs, worms, chrysalides, moths, the disease may manifest itself in all the organs,” wrote Dumas in his report to the Senate. “Whence does it come? how is it contracted? No one knows. But its invasion is recognized by little brown or black spots.” It was therefore called “corpuscle disease”; it was also designated as “_gattine_” from the Italian _gattino_, kitten; the sick worms held up their heads and put out their hooked feet like cats about to scratch. But of all those names, that of “pébrine” adopted by Quatrefages was the most general. It came from the patois word _pébré_ (pepper). The spots on the diseased worms were, in fact, rather like pepper grains. The first symptoms had been noticed by some in 1845, by others in 1847. But in 1849 it was a disaster. The South of France was invaded. In 1853, seed had to be procured from Lombardy. After one successful year the same disappointments recurred. Italy was attacked, also Spain and Austria. Seed was procured from Greece, Turkey, the Caucasus, but the evil was still on the increase; China itself was attacked, and, in 1864, it was only in Japan that healthy seed could be found. Every hypothesis was suggested, atmospheric conditions, degeneration of the race of silkworms, disease of the mulberry tree, etc.--books and treatises abounded, but in vain.