not, it is true, fully keep their past; but a fixed relation to it
they do keep, and under certain conditions may return to it again. The
transforming changes of chemistry, then, are of a different nature
from those of the mechanic destruction just described. In those the
ruined organism leaves not a wrack behind. In chemic change something
definite is held, something that originally was planned and can he
prophesied. An end is attained: the fixed combination of just so much
oxygen with just so much hydrogen for the making of the new substance,
water. Here change is productive, and is not mere waste, as in organic
destruction. Something, however, is lost--the old qualities; for these
cannot be restored except through the disruption of the new substance,
the water in which they are combined.



VI

But there is a more peculiar change of a higher order still, that
which we speak of as development, evolution, growth. This sort of
change might be described as movement toward a mark. When the seed
begins to be transformed in the earth, it is adapted not merely to the
next stage; but that stage has reference to one farther on, and that
to still others. It would hardly be a metaphor to declare that the
whole elm is already prophesied when its seed is laid in the earth.
For though the entire tree is not there, though in order that the seed
may become an elm it must have a helpful environment, still a certain
plan of movement elmwards is, we may say, already schemed in the seed.
Here accordingly, change--far from being a loss--is a continual
increment and revelation. And since the later stages successively
disclose the meaning of those which went before, these later stages