The bones have very strongly marked physical properties. Solidity and
hardness are their peculiar portion; they derive these properties
from the phosphate of lime which penetrates them, thus they are
constantly increasing with age, because this substance becomes more
and more predominant. Elasticity is another physical property of the
bones, which is found combined with the two preceding, but which is
in an inverse order; as it is in the gelatinous substance, in the
cartilaginous portion of the bone that it resides, it is, like this
portion, greater in childhood. In old age, the bones lose entirely
their suppleness and elasticity; they break more easily. Elasticity
is more evident in the long and small bones, than in those which are
larger; the fibula bends and evidently goes back again, this the tibia
could not do without difficulty. It is not that the one is more elastic
than the other, but it is that its conformation is more favourable to
the development of this property.