Besides the needle and shower, as above, the tonic bathing appliances may include an ordinary horizontal douche that can be pointed in any direction, a spray, or large rose, and a "wave." These three appliances may be placed together as at Fig. 15. They are connected to the pipes from the regulating valves by means of a foot or so of flexible hose. To this is secured a tapering copper pipe. The douche has a gunmetal nozzle. It is directed against the back and spine, but must not be used upon the head or chest. With a good head of water this is a most powerful appliance, feeling more like a rod of some solid substance pressing against one than a stream of water. The "wave" is formed by a copper spreader. The spray is simply a large rose, 6 in. or 8 in. diameter. [Illustration: FIG. 16. Regulating Valves for Needle, Douche, &c.] It may be found convenient to arrange the valves for the whole of the above-mentioned appliances together, as at Fig. 16. Each pair of hot and cold handles are here brought together. These handles should be long, so as to admit of easy regulating of the temperature of the water; they may well be 9 in. in length. The douche, wave, and spray should be kept as close as possible to the handles that regulate their temperature. I would repeat the caution that it is very necessary to beware of complications in these water-fittings and appliances. Some of the more "fussy" contrivances--as, for example, the elaborated needle bath as above described--require so much regulating, and so many valves and stop-cocks, that it is quite an undertaking for the attendant to set them going. Simplicity in design and construction should be observed in this work: the pipes as few as need be; the valves as simple as possible; and the whole put together in a manner that will permit of their being easily examined and repaired.