In particular, Pasteur noted its ability to “rotate the plane of polarized light”, and its “unsymmetric arrangement of atoms."[1] These behaviors were characteristic of organic compounds Pasteur had previously examined, but also presented a hurdle to his own research about a "law of hemihedral correlation".[2][7] Pasteur had previously been attempting to derive connections between substances' chemical structures and external shape, and the optically active amyl alcohol did not follow his expectations according to the proposed 'law'.[6] Pasteur sought a reason for why there happened to be this exception, and why such a chemical compound was generated during the fermentation process in the first place.[6] In a series of lectures later in 1860, Pasteur attempted to link optical activity and molecular asymmetry to organic origins of substances, asserting that no chemical processes were capable of converting symmetric substances (inorganic) into asymmetric ones (organic).[6] Hence, the amyl alcohol observation provided some of the first motivations for an biological explanation of fermentation.