apter, the second hypothesis need not
be considered.

If, then, new species are and have been evolved from pre-existing material,
must that material have been organic or inorganic?

As before said, additional arguments have lately been brought forward to
show that individual organisms _do_ arise from a basis of _in_-organic
material only. As, however, this at the most appears to be the case, if at
all, only with the lowest and most minute organisms exclusively, the
process cannot be observed, though it may perhaps be fairly inferred.

We may therefore, if for no other reason, dismiss the notion that highly
organized animals and plants can be suddenly or gradually built up by any
combination of physical forces and natural powers acting externally and
internally upon and in merely inorganic material as a base.

But the question is, how have the highest kinds of animals and plants
arisen? It seems impossible that they can have appeared otherwise than by
the agency of antecedent organisms not greatly different from them.

A multitude of facts, ever increasing in number and importance, all point
to such a mode of specific manifestation.

One very good example has been adduced by Professor Flower in the
introductory lecture of his first Hunterian Course.[234] It is the
reduction in size, to a greater or less degree, of the second and third
digits of the foot in Australian marsupials, and this, in spite of the very
different form and function of the foot in different groups of those
animals.

A similarly significant evidence of relationship is afforded by processes
of the zygomatic region of the skull in certain edentates existing and
extinct.

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Again, the relation between existing and recent faunas of the different
regions of the world, and the predominating (though by no means exclusive)
march of organization, from the more general to the more special, point in
the same direction.

Almost all the facts brought forward by the patient industry of Mr. Darwin
in support of his theory of "Natural Selection," are of course available as
evidence in favour of the agency of pre-existing and similar animals in
specific evolution.

Now the new forms must be produced by changes taking place in organisms in,
after or before their birth, either in their embryonic, or towards or in
their adult, condition.

Examples of strange births are sufficiently com