The Collaborative International Dictionary of English v.0.48:

Melancholize \Mel"an*cho*lize\, v. i.
   To become gloomy or dejected in mind. --Barrow.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Melancholize \Mel"an*cho*lize\, v. t.
   To make melancholy.
   [1913 Webster]