en graft a part of one animal's
body into another animal's body, but the mechanical union which we
bring about must be changed into vital union to be a success, the
spirit of the body has to second our efforts. The same in grafting a
tree or anything else: the mechanical union which we effect must become
a vital union; and this will not take place without some degree of
consanguinity, the live scion must be recognized and adapted by the
stock in which we introduce it.

Living matter may be symbolized by a stream; it is ever and never the
same; life is a constant becoming; our minds and our bodies are never
the same at any two moments of time; life is ceaseless change.

No doubt it is between the stable and the unstable condition of the
molecules of matter that life is born. The static condition to which all
things tend is death. Matter in an unstable condition tends either to
explode or to grow or to disintegrate. So that an explosion bears some
analogy to life, only it is quickly over and the static state of the
elements is restored. Life is an infinitely slower explosion, or a
prolonged explosion, during which some matter of the organism is being
constantly burned up, and thus returned to a state of inorganic repose,
while new matter is taken in and kindled and consumed by the fires of
life. One can visualize all this and make it tangible to the intellect.
Get your fire of life started and all is easy, but how to start it is
the rub. Get your explosive compound, and something must break the
deadlock of the elements before it will explode. So in life, what is it
that sets up this slow gentle explosion that makes the machinery of our
vital economies go--that draws new matter into the vortex and casts the
used-up material out--in short, that creates and keeps up the unstable
condition, the seesaw upon which life depends? To enable the mind to
grasp it we have to invent or posit some principle, call it the vital
force, as so many have done and still do, or call it molecular force, as
Tyndall does, or the power of God, as our orthodox brethren do, it
matters not. We are on the border-land between the knowable and the
unknowable, where the mind can take no further step. There is no life
without carbon and oxygen, hydrogen and nitrogen, but there is a world
of these elements without life. What must be added to them to set up the
reaction we call life? Nothing that chemistry can disclose.

New tendencies and activities are