116 THE LIFE OF PASTEUR 



leagues, Quatrefages, born like Dumas in the Gard. Quatre- 

 fages attributed to an Empress of China the first knowledge 

 of the art of utilizing silk, more than 4,000 years ago. The 

 Chinese, in possession of the precious insect, had jealously 

 preserved the monopoly of its culture, even to the point of 

 making it a capital offence to take beyond the frontiers of the 

 Empire the eggs of the silkworm. A young princess, 2,000 

 years later, had the courage to infringe this law for love of 

 her betrothed, whom she was going to join in the centre of 

 Asia, and also through the almost equally strong desire to 

 continue her fairy-like occupation after her marriage. 



Pasteur appreciated the pretty legend, but was more in- 

 terested in the history of the acclimatizing of the mulberry 

 tree. From Provence Louis XI took it to Touraine : Catherine 

 de Medici planted it in Orleanais. Henry IV had some mul- 

 berry trees planted in the park at Fontainebleau and in the 

 Tuileries where they succeeded admirably. He also en- 

 couraged 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. Docu- 

 mentary 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 Kepublic ; 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 inva- 

 sion 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 



