Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class thiohemiacetals
                 1 Class monothiohemiacetals [R2C(SR')OH or R2C(OR')SH (R'≠H)]
                 2 Class dithiohemiacetals [R2C(SR')SH (R'≠H)]