The bubbles of gas, contained in the various gaseous waters, resting upon the surface of the body, produce an agreeable sensation of mild stimulation not unlike that which we feel when the surface of the body is gently tickled. The gaseous baths belong necessarily to the category of cool baths, and it is important to remember that waters which have been boiled no longer retain any gas, which is all expelled during the process of ebullition. When a gaseous water issues from the earth at a temperature too low for bathing purposes, it is very important that the water should be heated only to the temperature required for bathing, which is generally between 60° Fahr. and 98° Fahr. This is effected usually by means of a coil of hot water or steam-pipes beneath the bottom of the bath, and, by turning a tap, the bath attendant can produce any temperature which may be desired in a very short time. Water which has been previously _boiled_ or _heated to a high temperature_, and has been allowed to cool to fit it for bathing purposes, contains very little or no gas, and cannot be regarded as constituting a gaseous bath. Intending bathers should inquire very carefully into the manner of heating baths at these establishments. If the natural gaseous water be collected in reservoirs, and be allowed to lie in these reservoirs for any length of time before being used for the baths, the greater part of the contained gas will escape, and there will be a great discrepancy between the actual condition of the water used and the published analysis of such water. It is exceedingly unlikely that either carbonic acid or nitrogen contained in water is absorbed by the skin. The effect of these gaseous baths is due to their physical condition only (at least we have no satisfactory evidence to the contrary), and in no way to the absorption of the contained gases. Carbonic acid is only absorbed by the skin under the influence of great pressure, and when thus absorbed it produces a poisonous effect. At some bathing establishments, so-called baths of pure carbonic acid are administered, the patient being made to sit in a reservoir of the pure gas, but, of course, with his head out. We have also seen arrangements for directing a jet of carbonic acid gas upon different regions of the body, but we should be sorry to hazard any opinion as to the _modus operandi_, or the results of such a practice. In an ordinary water-bath, strongly impregnated with carbonic acid, there is occasionally some danger of too much gas escaping, and being consequently inhaled in undue quantities by the occupant of the bath.