138 LOUIS PASTEUR 



problem, the cause of the phenomenon with which 

 he was dealing. The results of his investigations 

 are collected in a work of two volumes entitled 

 "The Diseases of Silk Worms" (Les Maladies 

 des Vers de Soie), which he liked to have his stu- 

 dents read because of the examples of scientific 

 method which they contain. These volumes are of 

 permanent value not only for the information they 

 afford, but perhaps more as a record of an elabo- 

 rate experimental research which, despite many 

 false assumptions and errors of detail, led finally 

 to a clear understanding of an intricate subject. 



During the years spent upon the diseases of silk 

 worms Pasteur was occupied intermittently with 

 several other matters. He wrote an account of the 

 scientific work of his friend Claude Bernard, and, 

 at the request of Dumas, an article on the great 

 chemist, Lavoisier. He also continued some of his 

 investigations on wines, to which I have previously 

 alluded, and he devoted considerable attention to 

 the administration of the Ecole Normale. 



In 1865 he lost his father, and soon afterward 

 his youngest daughter, then two years old. The 

 following year an older daughter, Cecile, who was 

 twelve years of age was taken with typhoid fever 

 and died suddenly after a period of convalescence 



