The extent of the wound influences the rate of healing; it is only
natural that a long and deep wound should take longer to heal than a
short and superficial one, because there is so much more work to be
done in the conversion of blood-clot into granulation tissue, and this
again into scar tissue that will be strong enough to stand the strain on
the edges of the wound.


THE TRANSPLANTATION OR GRAFTING OF TISSUES

Conditions are not infrequently met with in which healing is promoted
and restoration of function made possible by the transference of a
portion of tissue from one part of the body to another; the tissue
transferred is known as the _graft_ or the _transplant_. The simplest
example of grafting is the transplantation of skin.

In order that the graft may survive and have a favourable chance of
"taking," as it is called, the transplanted tissue must retain its
vitality until it has formed an organic connection with the tissue in
which it is placed, so that it may derive the necessary nourishment from
its new bed. When these conditions are fulfilled the tissues of the
graft continue to proliferate, producing new tissue elements to replace
those that are lost and making it possible for the graft to become
incorporated with the tissue with which it is in contact.

Dead tissue, on the other hand, can do neither of these things; it is
only capable of acting as a model, or, at the most, as a scaffolding for
such mobile tissue elements as may be derived from, the parent tissue
with which the graft is in contact: a portion of sterilised marine