The Collaborative International Dictionary of English v.0.48:

discussive \dis*cuss"ive\, a. [Cf. F. discussif.]
   1. (Med.) Able or tending to discuss or disperse tumors or
      coagulated matter; discutient.
      [1913 Webster]

   2. Doubt-dispelling; decisive. [R.]
      [1913 Webster]

            A kind of peremptory and discussive voice.
                                                  --Hopkins.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discussive \Dis*cuss"ive\, n. (Med.)
   A medicine that discusses or disperses morbid humors; a
   discutient.
   [1913 Webster]