PASTEUR: A STUDY IN GREATNESS 9 



His usual examination fortune attended him upon this occasion. 

 His classmates, who were wise in their generation, merely cramming 

 for the test, came through with flying colors while his name appeared 

 near the bottom of the list. And in the state examination which fol- 

 lowed, his name was put next to the last. Apparently his not being re- 

 jected was due solely to the excellence which he displayed in the prac- 

 tical phase of the examination wherein the candidates went through the 

 form of actually teaching a class. The lessons in physics and chemistry 

 given by Pasteur caused the jury to declare " he will become an excel- 

 lent teacher." 



He was appointed laboratory assistant to Laurent, the first to for- 

 mulate an hypothesis of the substitution of hydrogen in hydrocarbons. 

 This theory was elaborated, and enunciated in its final form, by Dumas 

 in 183-1. At this time, Laurent was working on sodium tungstate. 

 One day he showed his assistant, under the microscope, some crystals of 

 this salt supposedly pure but which manifested three distinct forms of 

 crystallization. Pasteur began at once to learn how to use the goniom- 

 eter. In order to master its technique, he made elaborate measure- 

 ments on all easily crystallizable tartrates, thus revealing the fact that 

 his curiosity concerning the two known tartaric acids had remained 

 lively throughout the preceding two years. 



In the meantime he was working toward the doctorate, which he 

 achieved August 23, 1847, on the strength of two small papers, the one 

 entitled "Researches on the Saturation Capacities of Arsenious Acid: 

 A Study of the Arsenites of Soda, Potassa and Ammonia," and the 

 other " A Study of the Phenomena Relative to the Polarization of 

 Liquids." 



He himself said of these papers, " They are elementary, and little 

 more than programs for future work." Again he attained but poor 

 ranking. 



He now desired to study in Germany; but poverty frustrated his 

 plans. On March 20, 1848, he read before the Academie des Sciences a 

 part of a paper on dimorphism which was little more than a catalogue 

 of all known substances crystallizing in two forms. Of itself, one 

 might say that it was almost valueless. But to the student of Pasteur's 

 life it was a proof that his work on the tartrates was still being prose- 

 cuted ; and it afforded an index pointing out the tenacious purpose and 

 the resolute will of the man. 



After a flash of republican ardor in 1848, in which he not only vol- 

 unteered service but also contributed to the cause all his savings, 150 

 francs, he returned to his crystals, and soon had the fortune to discover 

 hemihedrism in the tartrates, a fact that had escaped the scrutiny of 

 Mitscherlich and of Provostaye. 



So far as his investigations showed, all crystals of tartaric acid had 



