XIV INTRODUCTION 



Mamma Duclaux in the apartment in the rue Montlosier. 

 It was truly good fortune for a beginner in science to 

 meet a master like Duclaux." In connection with Roux, 

 as beginner in chemistry, we have the following story. 

 Duclaux had given out a pinch of some salt for analysis. 

 "What is it, my friend?" and the test made, the young 

 man replied, "Sir, I think it is sulfate of copper." "Ah, 

 you think so? Truly? Eh, well, do it over again." 

 At the end of some hours, the pupil returns, "Sir, I 

 believe it is sulfate of copper." "Begin again, my 

 friend." But the third time he returns with indignation 

 in his eyes and voice a little vibrant as he says: "Sir, 

 it is sulfate of copper." "So it is, my friend, but you 

 see in chemistry it is necessary to know, not merely to 

 believe or to think." 



From Clermont-Ferrand, Duclaux went to Lyons, 

 where he remained five years as professor of physics, and 

 then to Paris (1878) as professor of meteorology in the 

 Agronomic Institute. Through all of these changes it 

 was bio-chemistry which held the first place in his affec- 

 tions, but he was geologist, physicist, meteorologist, 

 agronomist, and chemist, as well as learned in medicine, 

 in brewing and in the dairy industries. He loved to 

 contemplate one aspect of the universe as well as another. 

 To his friend M. Voigt he writes at this time from one 

 of his summer vacations in Fau. "I like the solitude 

 where I live so well that I imagine it ought to have as 

 much charm for my friends. I find myself particularly 

 happy in the country. Free labor and not at all pressing, 

 an independent life, very few books, almost no journals, 

 see how I regain possession of myself." 



At another time he wrote: "I am strongly attached 

 to the soil. I communicate with it. I think how many 

 generations of my fathers have lived in contact with it 

 and I take pleasure hi asking it about them. I never 



