Bath of surprise
The ducking treatment was never widely used, primarily because of the risk of death to the patient. Nevertheless, the idea slowly evolved into what became known as the bain de surprise, or bath of surprise, in which the patient was plunged into water without warning. The element of shock was considered essential to the procedure, which led to a fanciful design to insure sudden and unexpected immersion.
In keeping with available technology (and the ad hoc nature of much of early psychiatry), hydrotherapy as advocated by Helmont was performed outdoors, in a sea or pond. However, as institutions for the insane became increasingly widespread in the 18th century, water therapy moved indoors, inspiring the development of a wide variety of hydrotherapeutic apparatus.
The douche, or shower bath, was another early hydrotherapeutic method. It consisted of pouring cold water from a height over a patient's head to lessen the heat of madness or rouse the melancholic. Warm or tepid baths were also used to calm overwrought nerves or to induce sleep.