The Collaborative International Dictionary of English v.0.48:

Coniine \Co*ni"ine\ (? or ?), n.
   See Conine.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Conine \Co"nine\ (? or ?), n. [From Conium.] (Chem.)
   A powerful and very poisonous vegetable alkaloid found in the
   hemlock (Conium maculatum) and extracted as a colorless
   oil, C8H17N, of strong repulsive odor and acrid taste. It
   is regarded as a derivative of piperidine and likewise of one
   of the collidines. It occasions a gradual paralysis of the
   motor nerves. Called also coniine, coneine, conia, etc.
   See Conium, 2.
   [1913 Webster]