Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class amino acids [H2NCHRCOOH]
                 alanine
                 arginine
                 asparagine
                 aspartic acid
                 cysteine
                 glutamic acid
                 glutamine
                 glycine
                 histidine
                 isoleucine
                 leucine
                 lysine
                 methionine
                 ornithine
                 phenylalanine
                 proline
                 selenocysteine
                 serine
                 taurine
                 threonine
                 tryptophan
                 tyrosine
                 valine