32 LOUIS PASTEUR. 



proper to the species, a tendency which is potential 

 in the germ of each of them. In this germ, it is 

 to be feared, the dissymmetry of the dissymmetric 

 primordial substances which it embraces will always 

 manifest itself. Ah ! if spontaneous generation were 

 possible ; if we could form from mineral matter a 

 living cell, how much more accessible would the 

 problem become ! However this may be, we must 

 seek, by all possible means, to produce molecular 

 dissymmetry by the application of forces which have 

 a dissymmetric action. We must,' said Pasteur to 

 me on the day when, starting from the note of 

 Mitscherlich, he passed all these things in review, 

 ' we must invoke the action of solenoid or helix. En- 

 tangled at present in labours more than sufficient to 

 absorb whatever of ardour and of force still remains 

 to me, I have no longer time to occupy myself with 

 these questions.' But what great things are to be 

 done in following out this order of ideas, and what a 

 route will be opened to young men possessed of that 

 genius of invention which is evoked so often by per- 

 sistent work ! 



This complete opposition between artificial mineral 

 products and vegetable and animal ones was to Pasteur 

 a truth so well established that he found frequent 

 opportunity of affirming it under decisive circum- 

 stances. One day, a very skilful chemist, M. Dessaignes, 



