V. 



DISEASES OF SILKWORMS 



IT was in March, 1863, that Pasteur told Napo- 

 leon III. that his one ambition was "to discover 

 the causes of putrid and contagious diseases." In 

 the autumn of 1865, the cholera came from Mar- 

 seilles to Paris : in October, there were more than 

 200 cases a day : and Pasteur, Claude Bernard, 

 and Deville, made many experiments on the air of 

 a cholera- ward in the Lariboisiere Hospital.* In 

 1865, also, Pasteur took up the study of the silk- 

 worm disease. For near twenty years, the silk 

 industry had been going from bad to worse : France, 

 Italy, Spain, Greece, Turkey, China, were all 

 involved : the loss and the misery, down in the 

 South of France, were terrible : it needed only 

 a few more turns of the screw to squeeze the life 

 out of this great national industry. He set his 



* " Un jour que Henri Sainte- Claire Deville disait a 

 Pasteur, ' II faut du courage pour ce genre d'etudes,' Et le 

 devoir ? lui dit simplement Pasteur. Le ton donne ce mot 

 devoir, racontait Sainte-Claire Deville, valait tout un enseigne- 

 ment." Vie de Pasteur, chap. vi. 



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