The Collaborative International Dictionary of English v.0.48:

Sudatory \Su"da*to*ry\, a. [L. sudatorius, fr. sudare to sweat:
   cf. F. sudatoire. See Sweat.]
   Sweating; perspiring.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sudatory \Su"da*to*ry\, n.; pl. Sudatories. [L. sudatorium.]
   A bagnio; a sweating bath; a vapor bath.
   [1913 Webster]

         These sudatories are much in request for many
         infirmities.                             --Evelyn.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sudatory
    n 1: a medicine that causes or increases sweating [syn:
         sudorific, sudatory]
    2: a bathhouse for hot air baths or steam baths [syn:
       sudatorium, sudatory]