The Collaborative International Dictionary of English v.0.48:

Mannitic \Man*nit"ic\, a. (Chem.)
   Of, pertaining to, resembling, or derived from, mannitol.
   [1913 Webster]

   Mannitic acid (Chem.), a white amorphous substance,
      intermediate between saccharic acid and mannitol, and
      obtained by the partial oxidation of the latter.
      [1913 Webster]