When eggs seem to disagree or the system does not assimilate them well on account of the fat in the yolk, and eggs are desirable to supply the protein in the diet, the whites, which contain practically no fat, may be used. They should be well beaten and if digestion is weak they may be mixed with fruit juices.
The citric acid in lemons and oranges partially digests the egg, the gastric juice quickly changing it to peptone.
One method of preparing eggs, which is especially valuable for those having delicate stomachs, is in egg lemonade or orangeade. Thoroughly beat the egg, add the juice of half a lemon or orange, sugar to taste, and fill the glass with water.
Grape juice, cream, and cocoa, if assimilated, may be used in place of lemon or orange, in order to give variety when it is necessary to use eggs freely.
Eggnog is another means of taking raw eggs.
One method of testing the freshness of eggs is to drop them into a strong, salt brine made by adding two ounces of salt to a pint of water. A fresh egg will at once sink to the bottom. If the egg is three days old the surface of the shell will be even with the surface of the water and an egg two weeks old will float mostly above the surface.
The opinion is prevalent that a hard-boiled egg is difficult of digestion, but this depends entirely on the mastication. If it is masticated so that it is a pulp before being swallowed, a hard-boiled egg is readily digested.
A soft-boiled egg should not be boiled longer than three or four minutes, or better, should be put into warm water, be allowed to come to a boil, then set off the fire and the egg be allowed to remain in the water for ten minutes. This method cooks the egg through more evenly.
Another method of cooking the yolk evenly with the white is to put the egg in cold water, let the water come to a boil, and again immerse the egg in cold water. The immersing in cold water after boiling makes hard-boiled eggs peel readily.