The tonic appliances for treating the bather subsequently to the shampooing, the soaping, and the cleansing, are various. The most useful is the simple shower bath, with a very large rose, and amply supplied with water through a regulating valve. It is employed for thoroughly cleansing the bather before he enters the plunge, whose waters are for the common use of all. In many small baths its place is efficiently taken by an ordinary hand rose or spray of the kind shown at Fig. 15. The shower proper is usually fixed above the "needle" bath, as at Fig. 14, or formed by a continuation of the "backbone" of the needle. It is best to have separate regulating valves for the needle and shower, as at Fig. 16; but at Fig. 14 it is shown with a branch from the pipe conducting to the needle, and with stop cocks. The needle-bath is a skeleton-like structure having a large hollow backbone and branching ribs. The water ascends the backbone, and, passing into the ribs, squirts out of small holes punctured in their internal circumferences. The bather stands in the centre of the apparatus, with the ribs encircling him. The ribs should be of 1/2-in. copper piping, the backbone and lesser supports being of iron, 2-1/2 and 1-1/2 in. diameter respectively. In a convenient position for the attendant must be placed the regulating valve. A more elaborate contrivance may be made, which will include needle, shower, ascending shower, spinal douche, and back shower; but this should be left for hydropathic institutions and invalids. Simplicity in these matters should be the great desideratum. The above-named additions, however, may be briefly described. At Fig. 14 I have indicated the position of ascending shower. It would be connected with the pipe supplying needle and shower, and have a stop-cock. The spinal douche is a little nozzle behind the shower proper, and should have similar connection with the supply-pipe. The back shower or spinal spray would be a rose placed about half-way up the iron backbone, and be connected in the same manner. Avoid these complications in a bath for healthy persons. [Illustration: FIG. 14. A Needle Bath.] The needle bath is best left exposed, but it may be enclosed in a metal shield if desired. This bath may be placed in one of three positions--(1) in the shampooing room, (2) in a separate chamber, (3) in the plunge bath chamber. It is most conveniently placed where the bather passes it _en route_ from the washing room to the plunge. For this appliance a good head of water is absolutely essential, as with a low pressure it is very ineffective. The illustration shows the bath standing on iron shoes. If fixed in a corner, as ordinarily, it can be secured to the wall by such cramps or brackets as may be necessary. [Illustration: FIG. 15. Spray, Wave, and Douche Baths.]