Source : Webster's Revised Unabridged Dictionary (1913)

Digester \Di*gest"er\, n.
   1. One who digests.

   2. A medicine or an article of food that aids digestion, or
      strengthens digestive power.

            Rice is . . . a great restorer of health, and a
            great digester.                       --Sir W.
                                                  Temple.

   3. A strong closed vessel, in which bones or other substances
      may be subjected, usually in water or other liquid, to a
      temperature above that of boiling, in order to soften
      them.

Source : WordNet®

digester
     n : autoclave consisting of a vessel in which plant or animal
         materials are digested