A LABORIOUS YOUTH 23 



in his teachers, Dumas, Delafosse and Balard, 

 the last of whom took him as assistant in his 

 laboratory. 



What at this time was the object of Louis 

 Pasteur's researches? How was he going to 

 approach the great problems of science? It 

 seems as though a sort of predestination 

 marked out his scientific career. Pasteur, who 

 was destined to arrive finally at the vaccines of 

 hydrophobia, began with the study of crystals, 

 and his whole career was a sort of luminous 

 ascension, progressing, from the constitution of 

 matter and its processes, all the way to the 

 transformation of microbes, the infinitely small 

 yet most redoubtable enemies of man, into 

 curative agents. 



Crystalography was then a new science, with 

 hesitant and controverted formulas. Essen- 

 tial phenomena remained without explanation, 

 and others were still undiscovered, escaping all 

 observation and all control. In order to judge 

 adequately of the inspired novelty of Pasteur's 

 discoveries it is necessary to understand the 



