The medicated vapour baths are of two kinds, _mercurial_ and _sulphur_, both being contrived by evaporating flour of sulphur or calomel in an iron pan. The sulphur bath thus administered emits the pungent and suffocating vapour of sulphurous acid, the effects of which must be exerted solely upon the body of the patient, since the inhalation of any quantity, if not fatal, would prove a very serious annoyance. We must not forget to mention the old domestic remedy of a bath of _mustard and water_, which is among the most powerful stimulants to the skin which we possess. The _Galvanic Bath_ has been much talked about of late years, and it becomes necessary that we should discuss its merits. It consists merely of a bath of water, through which a galvanic current is passed. It can be easily administered in the following way:--Place an ordinary bath upon a sheet of mackintosh, which, being a non-conductor of electricity, has the effect of insulating the bath, as it is termed. Then fill the bath with warm water to a convenient height, and to the water add a handful of salt or a wine-glassful of vinegar in order to increase its conducting power. Next get a galvanic battery, one having 30 or 40 Leclanché Elements is sufficient, and place it on a chair or on the floor beside the bath. To each of the poles of this battery, positive and negative, affix a suitable length (3 or 4 yards) of insulated telegraph wire, having its extremities freed from the gutta-percha or other insulating material. Place a length of stout broom-handle across the bath, resting on its two edges, and round the middle of this twine the bright metal end of the wire in connection with the positive pole of the battery, covering it with a piece of flannel, or wrapping it round with a sponge. The bather then gets into the bath, and takes hold of the centre of the broom-handle, previously moistened, so that his hands are out of the bath. The end of the negative wire is then placed in the bath itself, and as this is done the bather will feel the shock of the electric current. The current in this case travels from the positive pole of the battery through the wire to the broom-handle, down the patient’s arms, through his body to the water of the bath, and so to the negative pole. This form of bath is a very powerful stimulant to the skin, but beyond its action on the skin we know nothing. It is said that by its aid it is possible to extract metallic bodies, such as mercury or lead, which may be lurking in the body and causing harm. Of such a power there is no evidence whatever. We have heard it said that at some galvanic baths visitors have been shown discolorations on the side of the bath as evidence of deposits of mercury, &c., but this is merely a quackish imposition, and it is well that persons should be on their guard against it. The _electro-magnetic_ bath is given in the same way as the galvanic bath, an electro-magnetic battery being substituted for the galvanic battery.