Note 117 — Chapter IV

Here is an example in confirmation, taken from Duclaux's book on Pasteur: Herschel established a relation between the crystalline structure of quartz and the rotatory power of the substance; later on, Biot established it for sugar, tartaric acid, etc.—i.e., for substances in solution, whence he concluded that the rotatory power is due to the form of the molecule itself, not to the arrangement of the molecules in relation to one another. Pasteur discovered a relation between molecular dyssymmetry and hemiedry, and the study of hemiedry in crystals led him logically to that of fermentation and spontaneous generation.