1775, that if the internal membrane, or
medullary periosteum, is destroyed, the bone decays
away, whilst around this dead and decaying
bone the external periosteum forms a new bone.
The growth of bone, in fact, is the gradual
transformation of membrane into cartilage, and
cartilage into bone. By making a hole in a
bone, and destroying the internal membrane
through it, M. Flourens proved that the external
membrane could produce a new bone, the
internal membrane of which gradually absorbed
the whole of the old bone.

And the practical results of these experiments
have been found already to be as beneficent as
wonderful. The principles of a new surgery
have issued out of them. They have shown
the inestimable importance of preserving the
membrane which becomes bone, in surgical
operations. Complete amputations are becoming
more and more rare: extirpations of the injured
bones taking the place of them.

Dr. Philipeaux narrates a case which occurred
in the practice of M. Blandin. A young man
became a patient of the Hotel Dieu on account
of a fistulous wound in the upper and front part
of the chest, and in the direction of the left
collar-bone. On probing the wound, M. Blandin
found that it proceeded from a caries of nearly
all the interior half of the bone. Emollients
and dissolving pomades having no effect upon
the obstinate malady, and the patient growing
meagre and resolving to risk the worst, an
operation was determined on. Familiar with the
results of the physiological experiments of
M.Flourens on the periosteum, M. Blandin made
up his mind to be guided by them in his surgical
operations. He would try his utmost skill to
extirpate the decayed bone and preserve the
periosteum. He made an incision into the
upper surface of the collar-bone, from the middle
to the internal or sternal part, at each end of
which he made another incision resembling a T
with two branches. Then, laying the collar-bone
bare without and within, he inserted an instrument
made on purpose to protect the periosteum
and the soft parts around it. Succeeding in
these precautions, he successfully extracted the
diseased bone, and disjointed it at its sternal
end. Half the collar-bone having been
extirpated, the patient begged the surgeon to
examine the remaining half, as, if it were tainted,
he would prefer losing the whole at once to
undergoing another operation. When the
surgeon examined the remaining half of the bone,
he was obliged to tell the patient that it was
seriously attacked by caries, and ought to be
extirpated. The remaining half of the collar-bone
was extirpated, and thus the whole bone was
extirpated. So successfully, however, had the
operations been performed, that a short time
afterwards the young man left the hospital cured.
Eight mouths later this patient returned to the
hospital for another disease, and all the students
had opportunities of examining him. A new
collar-bone had been made by the periosteum; and
this new bone was already almost perfect, and
the young man could execute every natural
movement with his arm, nearly as well as ever
he could in his life.

Still more marvels. The series of experiments
from Belcher to Duhanel, from Duhamel
to Troja, and from Troja to Flourens, has
been continued by M. Oilier. The periosteum,
let us always remember, is the future
bone. If healthy, and kept healthy, this
membrane will always become a sound bone, in
the most unexpected and extraordinary
circumstances. M. Oilier took long strips of
periosteum, and, twisting it around muscles in
different ways, obtained bones of the most curiously
various forms: bones in circular forms, bones
in spiral shapes, bones even in the figure of
eight.

Within three or four days after being cut off,
a rag of transplanted periosteum has become
bone. A bit of periosteum taken completely
away from the bone, and placed under the skin,
has ossified, producing bony secretions and
tissues. For, the membrane is to the bone, it
might almost be said, what the seed is to the
plant, and the egg to the animal. Wherever the
periosteum can be grafted, there it will become
bone. If the membrane of one animal can be
grafted upon the tissues of another, it will become
bone. And not merely is this true of animals
of the same species, this is true of animals of
allied species. This sort of grafting succeeds
even between chewing and biting animals, such
as the rabbit and the dog. Success is almost
certain in this strange process of bone-making
when the grafting is upon animals of the same
species, becoming more and more uncertain, of
course, as they recede from each in the web of
life.

Wonderful as the story of these discoveries
with these applications already is, these interesting
and important experiments go on accumulating
and culminating in interest and importance.
Practical surgeons have heretofore, when
trepanning, made but small account of the
membrane which is called the dura mater of the
brain. M. Flourens, at the head of the physiologists,
has held that the dura mater was a periosteum,
every membrane which becomes bone being
a periosteum. M, Flourens recently took a
portion of the dura mater of one animal and put
it under the skin of another individual of the
same species, and in thirty or forty days
afterwards it had become a small bone!

The thrilling story thus told by physiological
experiments is confirmed by the representations
of the microscope. Under a powerful lens the
structure of periosteum and of bone is seen to
be identical. Both are nourished by the blood
which circulates through canals called the
Haversian canals, around which the process of
the formation of bone is most active. It is
through these canals that the earthy matter
precipitated from the blood carries down with
it the colouring matter of the madder. And
thus ends this narrative. Beginning with a
thoughtful surgeon dining on roast pork, it ends
—- for the present— with young men getting
healthy bones instead of damaged ones, and