50 PASTEUR AND AFTER PASTEUR 



beside that of infected leaves. A trayful of healthy 

 worms could be infected by the droppings from a 

 trayful of diseased worms put above them : and 

 diseased worms, put among healthy worms, could 

 infect them. On March 1, in a letter full of hope, 

 he is impatient over the general belief that the 

 country folk could not use a microscope " Don't 

 tell me that anybody wants anything simpler than 

 a preventive method which is just to put your eye 

 to the eye-piece of a microscope after pounding a 

 moth in a mortar with a few drops of water mere 

 child's-play, taking an hour or two to learn. A 

 deadlock here would be absurd, especially when 

 you think how we are dealing with a state of 

 things which means to France, let alone other 

 countries, the loss of 30, 40, or 50 million francs 

 a year, and to each proprietor the loss of his chief, 

 often his only, income." 



Then came another set of problems. Another 

 disease, called morts-flats or flacherie, broke out 

 among his worms : he had now to labour not over 

 one disease, but over two. Flacherie may be 

 defined as a septic disease of silkworms, due to the 

 eating of leaves contaminated by the specific germs 

 of the disease : leaves sodden with rain, or unclean 

 with dust, are apt to be thus contaminated. The 

 germs ofjftacherie are found in the digestive canal 

 of the worm, and in the stomach-pouch of the 



