136 LOUIS PASTEUR 



would be almost certain to produce eggs free from 

 both maladies. Pasteur produced and distributed 

 eggs which he could guarantee to be free from in- 

 fectious diseases, and which would give rise to 

 healthy worms provided they were protected from 

 new infection from the outside. 



"Would you like to find," Pasteur asks, "whether 

 a lot of cocoons will give you healthy eggs? Take 

 a part of them and heat them so as to hasten by 

 four or five days the hatching of the moths, and 

 see if they are corpuscular. ... If the moths are 

 infected send the cocoons to the spinning mills. 

 . . . But would you have the brood sound up to 

 the very end and give healthy eggs? In this case 

 take absolutely sound eggs derived from entirely 

 healthy parents and hatch them in clean and iso- 

 lated places to which infection cannot spread. But 

 if, unfortunately, the disease should arise, I still 

 give you the means of making a selection, and of 

 separating infallibly the sound eggs from the dis- 

 eased ones.'' 



By following Pasteur's directions the growers 

 found that they could check the destructive disease 

 of pebrine and also flacherie. The silk industry 

 soon felt the benefit of the improved methods. 

 The Lyons Silks Commission had asked Pasteur 



