The Collaborative International Dictionary of English v.0.48:

Mydatoxin \Myd`a*tox"in\, n. [Gr. myda^n to be clammy (from
   decay) + toxic + in.] (Physiol. Chem.)
   A poisonous amido acid, C6H13NO2, separated by Brieger from
   decaying horseflesh. In physiological action, it is similar
   to curare.
   [1913 Webster]