A wheat kernel may be subdivided into three layers. The first or outer
one contains the bran; second, the gluten, fats and salts; third, the
starch. Some of the mineral matter for which wheat is so valuable is
contained in the bran, hence the value of at least a portion of that
part of the wheat being included in bread flour--not by the addition
of coarse bran (which is indigestible) to the ordinary flour, but by
the refining process employed in producing whole wheat flour. While
wheat is used in other forms, its principal use as food is in the form
of flour.

The following table, giving the composition of bread from wheat and
maize, will be of interest (Stone):--


COMPOSITION OF BREAD FROM WHEAT AND MAIZE.

-------------------------+--------------------------------------------
| In Air-Dry Material.
+------+-----+-----+-------+--------+--------
| | | | | |Nitrogen
|Water.| Ash.| Fat.| Fibre.|Protein.| free
| | | | | |extract.
-------------------------+------+-----+-----+-------+--------+--------
|P.ct. |P.ct.|P.ct.| P.ct. | P.ct. | P.ct.
Bread from whole winter | | | | | |
wheat | 3.07 | 2.33| 1.22| 2.86 | 15.70 | 74.82
Bread from whole spring | | | | | |
wheat | 7.46 | 1.69| 1.24| 2.80 | 15.26 | 71.55
Bread from fine flour, | | | | | |
winter wheat |10.39 | .59| .32| .44 | 11.94 | 76.32