It is entirely different in old age. As the years multiply the system absorbs an abnormal and ever increasing amount of calcareous matter. The bones become unduly hard and brittle and are easily broken. Bony matter is liable to be deposited in and about the joints, when they become stiff and painful. It also lodges in the various soft tissues of the body, and ossification of the valves of the heart and walls of the arteries sometimes happens. It weakens the blood vessels so that they easily rupture, which causes apoplexy, paralysis and death. Calcareous concretions in the kidneys and bladder, also, come from the same cause, and are called gravel. Such deposits are not only annoying and painful to the patient, but in time may prove fatal if not removed by surgery. Middle-aged and elderly people should never drink anything but soft water. If a natural supply of soft water cannot be obtained distilled water should be substituted. If neither natural soft water nor distilled water are available, and there is doubt as to the purity of the water that is being used, it should be boiled and then let stand to cool and settle. Boiling not only destroys and renders harmless any organic germs that may be present, but also precipitates and eliminates much of its inorganic salts. A few drops of a weak solution of nitrate of silver added to a glass of water will quickly determine its quality. If the water that is being tested is free from mineral matter no change is produced, but if it contains mineral it turns the water opaque or milky. The value of mineral water as a healthful or necessary drink has been greatly exaggerated. While it may do good in some instances, it is not nearly as beneficial as is commonly supposed. Instead of it always doing good the contrary is often true. If a mineral water is desired there is no necessity of visiting a mineral spring to obtain it, as it can be made artificially at home or at the nearest pharmacy in any quantity or of any quality desired, with the additional advantage of having it contain exactly the ingredients wanted. There are nearly as many mineral waters on the market as there are patent medicines, and both are about equally misrepresented and deceiving. All classes of people would undoubtedly be greatly benefited in health, strength and longevity if more attention was given to the quality of our domestic water supply. Any one who needs a change, other things being equal, should seek a resort that furnishes pure, soft water rather than choose a spring that only boasts of its mineral properties. Not all of the benefit that is derived from a course at watering place is due to the virtues of the water, be it ever so potent. The change of environment, climate, diet, bathing, etc., are each factors that contribute something towards a cure.