Now, so far as we know, there is no natural limit to the existence of
the Euglena, or of any other living germ. A living species once launched
into existence tends to live for ever.

Consider how widely different this living particle is from the dead
atoms with which the physicist and chemist have to do!

The particle of gold falls to the bottom and rests--the particle of dead
protein decomposes and disappears--it also rests: but the _living_
protein mass neither tends to exhaustion of its forces nor to any
permanency of form, but is essentially distinguished as a disturber of
equilibrium so far as force is concerned,--as undergoing continual
metamorphosis and change, in point of form.

Tendency to equilibrium of force and to permanency of form then, are the
characters of that portion of the universe which does not live--the
domain of the chemist and physicist.

Tendency to disturb existing equilibrium,--to take on forms which
succeed one another in definite cycles, is the character of the living
world.

What is the cause of this wonderful difference between the dead particle
and the living particle of matter appearing in other respects identical?
that difference to which we give the name of Life?

I, for one, cannot tell you. It may be that, by and by, philosophers
will discover some higher laws of which the facts of life are particular
cases--very possibly they will find out some bond between