of which it has formed a
part, and is resolved into its inorganic elements, to be in due course
eliminated from the body by the organs of excretion."--Maclaren's
_Physical Education_.

[5] The periosteum is often of great practical importance to the surgeon.
Instances are on record where bones have been removed, leaving the
periosteum, within which the entire bone has grown again. The importance
of this remarkable tissue is still farther illustrated by experiments upon
the transplantation of this membrane in the different tissues of living
animals, which has been followed by the formation of bone in these
situations. Some years ago a famous surgeon in New York removed the whole
lower jawbone from a young woman, leaving the periosteum and even
retaining in position the teeth by a special apparatus. The entire jawbone
grew again, and the teeth resumed their original places as it grew.

[6] The mechanism of this remarkable effect is clearly shown by an
experiment which the late Dr. Oliver Wendell Holmes used to take delight
in performing in his anatomical lectures at the Harvard Medical College.
He had a strong iron bar made into a ring of some eight inches in
diameter, with a space left between the ends just large enough to be
filled by an English walnut. The ring was then dropped to the floor so as
to strike on the convexity just opposite to the walnut, which invariably
was broken to pieces.

[7] For the treatment of accidents and emergencies which may occur with
reference to the bones, see Chapter XIII.

[8] "Besides the danger connected with the use of alcoholic drinks which
is common to them with other narcotic poisons, alcohol retards the growth
of young cells and prevents their proper development. Now, the bodies of
all animals are made up largely of cells, ... and the cells being the
living part of the animal, it is especially important that they should not
be injured or badly nourished while they are growing. So that alcohol in
all its forms is particularly injurious to young persons, as it retards
their growth, and stunts both body and mind. This is the theory of Dr.
Lionel S. Beale, a celebrated microscopist and thinker, and is quite
generally accepted."--Dr. Roger S. Tracy, of the New York Board of Health.

[9] "In its action on the system nicotine is one of the most powerful
poisons known. A drop of it in a concentrated form was found sufficient to
kill a dog, and small birds perished at the approach of a