otion stops; eyes appear at the front of the
animal; a hump on the back begins to be covered with a shell, and the
little creatures, pushing from the jelly, start their life journey on
the side of the aquarium. Why did it happen? How did it happen? Here
we have seen creation at work. Here surely the hand of the Creator is
working in the only sense in which the Creator may be properly said to
have a hand. How the history of the substance out of which the egg was
produced provides for the future development of that egg no man has
yet clearly said. This is not to say that we shall never know, still
less is it to say that this can never be known. Ralph Waldo Emerson
has said that there is no question propounded by the order of nature
which the order of nature will not at some time solve. If he is right,
and I believe he is, we shall at some time know how it is that this
egg produces this snail. But, as I said before, nothing but the
frequency with which the process goes on under our eyes could possibly
blind us to the marvel of it.

The regularity with which each animal reproduces its kind is no more
surprising than the faithfulness of that reproduction. Some of our
birds have wonderful markings on their plumage. It is astonishing to
see with what fidelity the feather of a bird may reproduce the
corresponding feather of its parent. It will occur to everyone how, in
the human family to which he belongs, there is some little peculiarity
which, while not appearing in every member of the family, when it does
appear is remarkably uniform. It may be only the droop of an eyelid,
it may be a tendency to lift one side of the lip more than the other,
it may be the peculiar shape of a certain tooth in the set, and yet
when it appears it comes with astonishing similarity in all who
possess it. So much for the principle of Heredity.

The second great underlying idea is known by the name of Variation. We
have just been dwelling on the regularity with which parents produce
offspring like themselves. We must now draw attention to the fact
that, while it is true animals must absolutely belong to the same
genus or species, even to the same variety, none the less no animal is
exactly like his parents. Furthermore, in a group of animals produced
at the same time from the same parent each one will have at least some
small point in which he differs from every other one in the group. Two
animals may look alike at first to the undiscerning eye, b