The Collaborative International Dictionary of English v.0.48:

Eucalyn \Eu"ca*lyn\ ([=u]"k[.a]*l[i^]n), n. (Chem.)
   An unfermentable sugar, obtained as an uncrystallizable sirup
   by the decomposition of melitose; also obtained from a
   Tasmanian eucalyptus, -- whence its name.
   [1913 Webster]