e, by virtue of which it can later on prevail as the truth;
that so-called necessity is made up of the merely accidental, and that
the acknowledged accidental is the form behind which necessity conceals
itself and so on.

The old methods of enquiry and thought which Hegel terms metaphysics,
which by preference busied themselves by enquiring into things as given
and established quantities, and the vestiges of which still buzz in the
heads of people, had at that time great historical justification. Things
had first to be examined, before it was possible to examine processes;
man must first know what a thing was before he could examine the
preceding changes in it. And so it was with natural science. The old
metaphysic which comprehended things as stable came from a philosophy
which enquired into dead and living things as things comprehended as
stable. But when this enquiry had so far progressed that the decisive
step was possible, namely, the systematic examination of the preceding
changes in those things going on in nature itself, then occurred the
death-blow of the old metaphysics in the realm of philosophy. And, in
fact, if science to the end of the last century was chiefly a collecting
of knowledge, the science of actual things, so is science in our day
pre-eminently an arranging of knowledge, the science of changes, of the
origin and progress of things, and the mutual connection which binds
these changes in nature into one great whole. Physiology, which examines
the earlier forms of plant and animal organisms; embryology, which deals
with the development of the elementary organism from germ to maturity;
geology, which investigates the gradual formation of the earth's crust,
are all the products of our century.

But, first of all, there are three great discoveries which have caused
our knowledge of the interdependence of the processes of nature to
progress by leaps and bounds. In the first place, the discovery of the
cell, as the unit, from the multiplication and differentiation of
which, the whole of plant and animal substance develop so that not only
the growth and development of all higher classes of all higher organisms
is recognized as following a universal law, but the very path is shown
in the capacity for differentiation in the cell, by which organisms are
enabled to change their forms and make thereby a more individual
development. Secondly, the metamorphosis of energy which has shown us
that all the so-calle