160 LOUIS PASTEUK. 



pelled. Pasteur had arrived at such accurate know- 

 ledge both of the causes of the evil and their different 

 manifestations, that he was able to produce at will 

 either pebrine or flacherie. He could so regulate the 

 intensity of the disease as to cause it to appear on a 

 given day, almost at a given hour. He had now to 

 carry into practice the results of his laboratory 

 labours. 



Since the beginning of the plague, and after some 

 doubts which were soon dispelled, it was clearly seen 

 that all the mischief was to be attributed to the bad 

 condition of the eggs. The remedy of distant explora- 

 tions for procuring non-infected eggs was both insuffi- 

 cient and precarious. It simply amounted to going 

 very far to seek, and paying very dear, for seed 

 which could not be relied on with certainty. The 

 prosperity of the silkworm culture could only be 

 secured by measures capable of restoring to the native 

 eggs their pristine qualities. 



The results obtained by Pasteur were sufficient to 

 solve this problem. The struggle against flacherie 

 was easy, but there remained the struggle against 

 pebrine. To triumph over this disease, which was so 

 threatening, Pasteur devised a series of observations 

 as simple as they were ingenious. 



Here is a crop which has perfectly succeeded. The 

 moultings, and the climbing upon the heather, are all 

 that could be desired. The cocoons are finished, and the 



