ill any germs whatever.

Evidently the problem of the origin of life is not hopeless, but our
knowledge of the nature of living matter is still so imperfect that we
may leave detailed speculation on its origin to a future generation.
Organic chemistry is making such strides that the day may not be far
distant when living matter will be made by the chemist, and the secret
of its origin revealed. For the present we must be content to choose the
more plausible of the best-informed speculations on the subject.

But while the origin of life is obscure, the early stages of its
evolution come fairly within the range of our knowledge. To the inexpert
it must seem strange that, whereas we must rely on pure speculation
in attempting to trace the origin of life, we can speak with more
confidence of those early developments of plants and animals which are
equally buried in the mists of the Archaean period. Have we not said
that nothing remains of the procession of organisms during half the
earth's story but a shapeless seam of carbon or limestone?

A simple illustration will serve to justify the procedure we are
about to adopt. Suppose that the whole of our literary and pictorial
references to earlier stages in the development of the bicycle, the
locomotive, or the loom, were destroyed. We should still be able to
retrace the phases of their evolution, because we should discover
specimens belonging to those early phases lingering in our museums, in
backward regions, and elsewhere. They might yet be useful in certain
environments into which the higher machines have not penetrated. In the
same way, if all the remains of prehistoric man and early civilisation
were lost, we could still fairly retrace the steps of the human race, by
gathering the lower tribes and races, and arranging them in the order
of their advancement. They are so many surviving illustrations of the
stages through which mankind as a whole has passed.

Just in the same way we may marshal the countless species of animals and
plants to-day in such order that they will, in a general way, exhibit
to us the age-long procession of life. From the very start of living
evolution certain forms dropped out of the onward march, and have
remained, to our great instruction, what their ancestors were millions
of years ago. People create a difficulty for themselves by imagining
that, if evolution is true, all animals must evolve. A glance at our own
fellows will show the error of