86 PASTEUR 



studied by Guerin-Menneville, Lebert and 

 Frey, Osimo, Cantoni and de Quatrefages, the 

 latter of whom gave its name to the most re- 

 doubtable of these diseases, pebrine. In this 

 disease the bodies of the infected worms be- 

 came covered over with spots resembling grains 

 of pepper. It was known in a vague way that 

 it was caused by corpuscles, but, when it be- 

 came a question of determining their nature 

 and the manner of their invasion, there was 

 nothing but darkness and contradictions. As 

 for remedies, they were purely empirical; re- 

 sort was had to sulphur, sugar, ground mus- 

 tard, ashes, etc., and all of them were quite in 

 vain. 



Pasteur had to find his way through an in- 

 extricable labyrinth, without any special knowl- 

 edge, and armed solely with his intuitive mind 

 and his unrivalled qualities as an investigator. 

 In his Histoire d'un Esprit Duclaux, who, to- 

 gether with Gernez and Maillot, was his col- 

 laborator at Pont-Biquet, relates all the fluctu- 

 ations of that six years' struggle, with its mis- 



