Albumen is a substance found in many foods in both solid and liquid forms.

The white of eggs is nearly pure albumen. The yolks contain a smaller portion of it. The albumen in the white of egg is in a clear, liquid form; but if we put an egg into boiling water, the white soon becomes opaque, thick, and creamy, then tough, and finally the white is quite hard and brittle, and the yolk dry and mealy, or easily crumbled. The two kinds of albumen in the egg coagulate at 122° and 160° F.

Blood albumen is found in the juices and fibres of lean meat. A piece of lean meat, if put into boiling water, shrivels and contracts, and the juices stay in the meat. The water is unchanged. But these small pieces of meat which were put into cold water at the beginning of the lesson have colored the water red and given it a taste, which shows that the juices have been drawn into the water. On heating this water, we find the red color changes to brown, and the water seems thicker. Soon the brown substance becomes harder, separates entirely from the water, and, when the water stops boiling, settles. Blood albumen coagulates at 160°.

By this experiment we have learned that cold water draws out albuminous juices and holds them in solution, and that boiling water hardens albumen.

Nearly all vegetables contain starch and a small amount of albuminous matter, and are generally cooked in water.

We shall learn to-day about cooking potatoes; and as the principles are the same for cooking all vegetables, if we learn how to cook one kind well, we can, by following the special directions, cook any kind as occasion may require.