The Collaborative International Dictionary of English v.0.48:

Calenture \Cal"en*ture\, n. [F. calenture, fr. Sp. calenture
   heat, fever, fr. calentar to heat, fr. p. pr. of L. calere to
   be warm.] (Med.)
   A name formerly given to various fevers occuring in tropics;
   esp. to a form of furious delirium accompanied by fever,
   among sailors, which sometimes led the affected person to
   imagine the sea to be a green field, and to throw himself
   into it.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Calenture \Cal"en*ture\, v. i.
   To see as in the delirium of one affected with calenture.
   [Poetic]
   [1913 Webster]

         Hath fed on pageants floating through the air
         Or calentures in depths of limpid flood. --Wordsworth.
   [1913 Webster]