Natura - nature actualia - actual entities Mundus Plinius - physical world naturalia - natural bodies "crystal-kingdom" chemical substances chemical compounds Class alcohols [ROH (R≠H)] Class amino alcohols Class sphingoids (4E,14E)-sphinga-4,14-dienine [C18H35NO2; HOCH2CH(NH2)CH(OH)CH=CH[CH2]8CH=CH[CH2]2CH3]