We are also assured of ash in any ordinary diet, but some attention should be paid to kind and amount, especially as many common foods have lost the parts richest in ash. Patent flour, for instance, made from the inner part of the grain, is not so rich in ash as whole or cracked wheat. Valuable salts are also lost in cooking vegetables when the water in which they were cooked is thrown away. If not desired with the vegetable, this should be saved for gravy or soup. It is not necessary to calculate a definite amount of ash for the diet, if ash-bearing foods are freely used. By reference to the table on page 384 you can see what foods are valuable for supplying the important kinds of ash. Milk is particularly rich in calcium and hence is required when the bones are growing. Eggs have iron and phosphorus in forms well suited to growth. But if eggs are too expensive, the vegetables and fruits generally will supply these same substances.