The uses of these waters are the same as the purely medicinal preparations of iron. They are indicated in chlorosis and anaemia, to supply to the blood the material in which it is deficient. For this purpose the milder waters, containing carbonate of iron and abundant carbonic acid, are most suitable; for example, in this country, Bedford (Pennsylvania)—Columbian Spring, Saratoga, and the "Sweet," of Virginia, etc.; in England, Bascombe and Tunbridge; on the Continent, Pyrmont, Spa, Schwal-bach, St. Moritz. When passive haemorrhages—the haemorrhagic diathesis—require ferruginous waters, the alum and iron waters are more effective. Amenorrhoea, hysteria, and other pelvic disorders, when dependent on anaemia, the paludal cachexia, leucocythemic-exophthalmic goitre, are either cured or decidedly ameliorated by chalybeate waters.

The purgative iron waters are useful in engorgement of the liver, hemorrhoids, and dyspepsia of anaemic subjects, in albuminuria and dropsy; the alum springs in chronic diarrhoea and strumous diseases.

Neuralgia, chorea, cerebral anaemia, and other nervous disorders due to an impoverished condition of the blood, are much improved by the use of the milder chalybeate waters.

In making selection of a chalybeate water the psychical influences of mountain scenery, or other pleasant surroundings, should not be disregarded. For the anaemic pulmonary invalid, elevation of the spring and the absence of humidity are important considerations to determine a selection. Hence, the present popularity of St. Moritz. In this country a great variety is afforded—mountain scenery like Bedford, Pennsylvania, and the Virginia springs, or rolling upland like Bailey's and Sharon. As respects composition, the ferruginous springs of the United States are equal to any in the world.

For authorities referred to, see articles on Alkaline and Saline Springs.

The remedies promoting constructive metamorphosis previously considered are constituent elements of the human body. Those now to be discussed act indirectly, by stimulating the organs concerned in blood-making.