

SILKWORM DISEASE 115 



a soie. Si j'avais une partie de vos connaissances sur 

 le sujet, je n'hesiterais pas,' he wrote to his friend ; 

 but in spite of his hesitation, he left for Alais, and at 

 once commenced a campaign which lasted during the 

 summers of the next five years. Almost immediately 

 on his arrival he detected in the sick silkworms the 

 corpuscles of Cornalia and Filippi, which we now call 

 the Micrococcus ovatus. These micrococci are com- 

 paratively large and very bright ; they occur in the 

 tissues and blood of the silkworm, and are found even 

 in the eggs of the moth. They cause the disease 

 known as Pebrine. The occurrence of the micrococci 

 in the eggs was one of the most important new facts 

 observed by Pasteur. It was the first recorded 

 instance of a parasitic organism being conveyed from 

 one generation to another by the egg ; and, although 

 recently the germ of the Texas fever (allied to the 

 malarial organism) has been shown to pass from one 

 brood to another through the egg of the tick which con- 

 veys it, it is satisfactory to record that the cases in which 

 this occurs are restricted in number and comparatively 

 rare. The ease with which Micrococcus ovatus could 

 be detected suggested a remedy. A child, when 

 trained, can readily identify the organism. Healthy 

 moths produce sound eggs and healthy larvae ; diseased 

 moths produce diseased progeny. At the present day, 

 throughout the silkworm districts of the South of 

 France, as soon as the moth has deposited her eggs 

 on the piece of linen provided for that purpose, she is 

 pinned up with the cloth ; and during the ensuing 

 autumn and winter the women and children are occu- 

 pied in microscopically examining the body of the 

 moth, crushed in a little water, for traces of the micro- 

 coccus. Should any be found, the eggs on the corre- 

 sponding piece of linen are at once destroyed. Pasteur 

 also showed that the infected stock spread the disease 

 by distributing the micrococci on the mulberry-leaves, 



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