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
                   02.0 [2-aminoethanol [HOCH2CH2NH2]] see ethanolamine [HOCH2CH2NH2]
                   18 Class sphingoids