Soft water, that is, water containing no lime or other mineral, is best. Hard water which causes any degree of curdling of soap, or a lime crust in the bottom of a teakettle, renders digestion difficult.
Bacteria are killed and much of the mineral matter is deposited by boiling the water. Boiled water tastes flat or insipid. It may regain its original, fresh taste by filling a jar half full of water, and shaking the jar so that the air passes through the water.
SALTS
The salts of sodium, potassium, magnesium, calcium and some other substances, are necessary for proper bodily functioning. Taken with the food, they pass into the tissues without change and can be recovered, unchanged, from the tissues and the urine.
The uses of some of these substances are not thoroughly understood, but if deprived of them, the nutrition of the body suffers.
Lime (calcium) is necessary for the bones and teeth and to preserve the coagulability of the blood.
Sodium chlorid (common salt) aids the formation of hydrochloric acid and the activity of the pancreatic juice.
The salts of iron are necessary for the blood.
Other salts are also needed to carry on the chemical reactions in the digestive system.
Cereals, all vegetables, fruits, and nuts furnish both calcium salts and sodium, potassium, and magnesium, which are the salts in the blood and lymph. Minerals are also abundant in dried legumes (beans and peas).