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of life. But he did not look upon it as an impassable one, and 

 he was careful to say, "It is a distinction of fact and not of 

 absolute principle." As nature elaborates immediate principles 

 of life by means of dissymmetrical forces, he wished that the 

 chemist should imitate nature, and that, breaking with methods 

 founded upon the exclusive use of symmetrical forces, he should 

 bring dissymmetrical forces to bear upon the production of chem- 

 ical phenomena. He himself, after using powerful magnets to 

 attempt to introduce a manifestation of dissymmetry into the 

 form of crystals, had had a strong clockwork movement 

 constructed, the object of which was to keep a plant in 

 continual rotatory motion first in one direction then in another. 

 He also proposed to try to keep a plant alive, from its germina- 

 tion under the influence of solar rays reversed by means of a 

 mirror directed by a heliostat. 



But Biot wrote to him : "I should like to be able to turn 

 you from the attempts you wish to make on the influence of 

 magnetism on vegetation. M. de Senarmont agrees with me. 

 To begin with, you will spend a great deal on the purchase of 

 instruments with the use of which you are not familiar, and of 

 which the success is very doubtful. They will take you away 

 from the fruitful course of experimental researches which you 

 have followed hitherto, where there is yet so much for you to do, 

 and will lead you from the certain to the uncertain." 



" Louis is rather too preoccupied with his experiments," 

 wrote Mme. Pasteur to her father-in-law; "you know that 

 those he is undertaking this year will give us, if they succeed, 

 a Newton or a Galileo." 



But success did not come. " My studies are going rather 

 badly," wrote Pasteur in his turn (December 30). " I am 

 almost afraid of failing in all my endeavours this year, and 

 of having no important achievement to record by the end of 

 next year. I am still hoping, though I suppose it was rather 

 mad to undertake what I have undertaken." 



Whilst he was thus struggling, an experiment, which for 

 others would have been a mere chemical curiosity, interested 

 him passionately. Kecalling one day how his first researches 

 had led him to the study of ferments : " If I place," he said, 

 " one of the salts of racemic acid, paratartrate or racemate of 

 ammonia, for instance, in the ordinary conditions of fermenta- 

 tion, the dextro-tartaric acid alone ferments, the other remains 

 in the liquor. I may say, in passing, that this is the best means 



