THE DISEASES OF SILK WORMS 135 



that cases of pebrine without the corpuscles were 

 not pebrine at all, but flacherie. The eggs without 

 corpuscles which were supposed to produce pebrine 

 were found to produce the other disease instead. 

 In all cases of true pebrine there were the charac- 

 teristic corpuscles, and in all cases of flacherie the 

 characteristic bacteria. The discovery of two dis- 

 eases where there was supposed to be only one re- 

 moved most of the objections that prevented Pas- 

 teur from concluding that the corpuscles were the 

 cause of the disease instead of its product. It was 

 clearly established that without the corpuscles no 

 pebrine could occur. The difficulty in regard to 

 the mode of multiplication of the corpuscles is now 

 resolved. As this parasite is now known to belong 

 to the Sporozoa, a group with which Pasteur had 

 little familiarity, it is not surprising that no evi- 

 dence of fission was discovered, as the members of 

 this group multiply by the formation of spores 

 within the body of the parent organism. 



The discovery by which Pasteur was at first so 

 upset resulted in bringing order out of chaos, and 

 it also resulted in perfecting methods for checking 

 not only pebrine but flacherie as well. Diagnosis 

 of both diseases now became certain. It could now 

 be ascertained by examination of moths which ones 



