once. Our
knowledge no doubt in this as in any other province of nature is but the
merest fraction of what may be known therein. But there is no evidence
whatever to show that what we have observed is not a fair sample of the
whole. And so taking it, we find that the mass of evidence in favour of
the evolution of plants and animals is enormously great and increasing
daily.
Granting then the high probability of the two theories of Evolution,
that which begins with Laplace and explains the way in which the earth
was fitted to be the habitation of living creatures, and that which owes
its name to Darwin and gives an account of the formation of the living
creatures now existing, we have to see what limitations and
modifications are necessarily attached to our complete acceptance of
both.
First, then, at the very meeting point of these two evolutions we have
the important fact that all the evidence that we possess up to the
present day negatives the opinion that life is a mere evolution from
inorganic matter. We know perfectly well the constituents of all living
substances. We know that the fundamental material of all plants and all
animals is a compound called protoplasm, or that, in other words,
organic matter in all its immense variety of forms is nothing but
protoplasm variously modified. And we know the constituent elements of
this protoplasm, and their proportions, and the temperatures within
which protoplasm as such can exist. But we are quite powerless to make
it, or to show how it is made, or to detect nature in the act of making
it. All the evidence we have points to one conclusion only, that life is
the result of antecedent life, and is producible on no other conditions.
Repeatedly have scientific observers believed that they have come on
instances of spontaneous generation, but further examination has
invariably shown that they have been mistaken. We can put the necessary
elements together, but we cannot supply the necessary bond by which
they are to be made to live. Nay, we cannot even recall that bond when
it has once been dissolved. We can take living protoplasm and we can
kill it. It will be protoplasm still, so far as our best chemistry can
discover, but it will be dead protoplasm, and we cannot make it live
again; and as far as we know nature can no more make it live than we
can. It can be used as food for living creatures, animals or plants, and
so its substance can be taken up by living protoplasm and
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