matter. The protein, which is chiefly in the form of albumen, and the
fat are the most digestible of these elements, while the mineral
constituents are as valuable for the growing child as for the chick.
When the total weight of an egg is taken into consideration, the shell
constitutes about 11 per cent., the yolk 32 per cent., and the white 57
per cent. The composition of the yolk and the white differs somewhat,
the yolk having the greater food value, a fact that is also clearly
indicated in the chart. The white contains a larger proportion of water
than the yolk, but the yolk contains the most of the fat and more
protein and mineral matter, or ash, than the white. In addition, the
chart shows that the number of calories to the pound of whole egg is
700, of egg yolk is 1,608, and of egg white is 265.

7. PROTEIN IN EGGS.--The nature of the food substances in eggs is of
nearly as great importance as their amount, for they not only determine
the value of this food in the body, but influence its cooking. That
protein is present in both the yolk and the white is apparent from the
fact that they coagulate when heat is applied. Because eggs are high in
protein, containing 14.8 per cent. of this substance, they may be
regarded as equivalent to a meat dish, and it is only when they are
extremely high in price that they cannot be frequently substituted for
meat to advantage. They are often used to take the place of milk, too,
for eggs and milk are more alike in nutritive value than any other two
protein foods; but, of the two, milk yields the cheaper form of protein.
Like meat and milk, eggs are rich in all those food materials which
enter into the construction of bone, muscle, and blood.

8. FAT IN EGGS.--A study of the food chart previously mentioned will
show that eggs contain proportionately almost as much fat as protein and
that nearly all this fat is found in the yolk. Since fat produces more