n directed
into its _general_ course of development as _plant or animal_, will
again only obey a certain course of development in its own line.

But we must proceed a step further; for those who would believe in the
sufficiency of unaided Evolution, bid us bear in mind how very
elementary the dawn of instinct or the beginning of reason is in the
lowest forms which are classed as animal, and how very small is the
gap[1] between some highly organized plants and some animal forms, and
argue therefore that they may justly regard the distinction as of minor
importance, and hope that the "missing link" will be yet discovered and
proved. At any rate, they minimize the difference, and urge that it is
of no account if at least they can establish the sufficiency of a proved
development extending unbroken from the lowest to the highest animal
form. And having fixed attention on this side, no doubt there is a long
stretch of smooth water over which the passage is unchecked.

[Footnote 1: At the risk of repetition I will remind the reader that
nature contains _nothing like_ a progressive scale from plant to animal.
It is _never_ that the highest plant can be connected with the lowest
animal as in one series of links. The animal kingdom and the plant
kingdom are absolutely apart. Both start from similar elementary
proteinaceous structures; and both preserve their development
upwards--each exhibiting _some_ of the features of the other. It is at
the bottom of each scale that resemblance is to be found, _not_ between
the top of one and the lowest members of the other.]

The Evolution theory is that all the different species of animals,
birds, and other forms of life have been caused by the accumulation and
perpetuation of numerous small changes which began in one or at most a
few elementary forms, and went on till all the thousands of species we
now know of were developed.[1] It _is_ a fact that all organic forms
have a certain tendency to vary. I need only allude to the many
varieties of pigeons, horses, cattle, and dogs which are produced by
varying the food, the circumstances of life and so forth, and by
selective breeding.

The contention then is: given certain original simple forms of life,
probably marine or aquatic--for it is in the water that the most likely
occur--these will gradually change and vary, some in one direction, some
in another; that the changes go on increasing, each creature giving
birth to offspring which