18651870 175 



nearly eight months. In northern Italy, as well as in Austria, 

 his process of cellular seeding was now applied with success. 



Before returning to France he went to Vienna and then to 

 Munich : he desired to talk with the German chemist, Liebig, 

 the most determined of his adversaries. He thought it im- 

 possible that Liebig 's ideas on fermentation should not have 

 been shaken and altered in the last thirteen years. Liebig 

 could not still be affirming that the presence of decomposing 

 animal or vegetable matter should be necessary to fermenta- 

 tion I That theory had been destroyed by a simple and decisive 

 experiment of Pasteur's : he had sown a trace of yeast in water 

 containing but sugar and mineral crystallized salts, and had 

 seen this yeast multiply itself and produce a regular alcoholic 

 fermentation. 



Since all nitrogenized organic matter (constituting the fer- 

 ment, according to Liebig) was absent, Pasteur considered that 

 he thus proved the life of the ferment and the absence of any 

 action from albuminoid matter in a stage of decomposition. 

 The death phenomenon now appeared as a life phenomenon. 

 How could Liebig deny the independent existence of ferments 

 in their infinite littleness and their power of destroying and 

 transforming everything? What did he think of all these new 

 ideas? would he still write, as in 1845 : " As to the opinion 

 which explains putrefaction of animal substances by the 

 presence of microscopic animalculse , it may be compared to that 

 of a child who would explain the rapidity of the Ehine current 

 by attributing it to the violent movement of the numerous mill 

 wheels of Mayence ? ' ' 



Since that ingeniously fallacious paragraph, many results had 

 come to light. Perhaps Liebig, who in 1851 hailed J. B. 

 Dumas as a master, had now come to Dumas' point of view 

 respecting the fruitfulness of the Pastorian theory. That theory 

 was extended to diseases ; the infinitely small appeared as dis- 

 organizers of living tissues. The part played by the corpuscles 

 in the contagious and hereditary pebrine led to many reflec- 

 tions on the contagious and hereditary element of human 

 diseases. Even the long-postponed transmission of certain 

 diseases was becoming clearer now that, within the vibrio of 

 flachery, other corpuscles were found, germs of the flachery 

 disease, ready to break out from one year to another. 



To convince Liebig, to bring him to acknowledge the 

 triumph of those ideas with the pleasure of a true savant, such 



