oak leaves, ash leaves, horse-chestnut leaves, etc., are each
represented, but there is one species only at the end of each
bough.

Though the trunk and all the inner boughs and leaves have
disappeared, yet there hang here and there fossil leaves, also in
mid-air; they appear to have been petrified, without method or
selection, by what we call the caprices of nature; they hang in
the path which the boughs and twigs would have taken, and they
seem to indicate that if the tree could have been seen a million
years earlier, before it had grown near its present size, the
leaves standing at the end of each bough would have been found
very different from what they are now. Let us suppose that all
the leaves at the end of all the invisible boughs, no matter how
different they now are from one another, were found in earliest
budhood to be absolutely indistinguishable, and afterwards to
develop towards each differentiation through stages which were
indicated by the fossil leaves. Lastly, let us suppose that
though the boughs which seem wanted to connect all the living
forms of leaves with the fossil leaves, and with countless forms
of which all trace has disappeared, and also with a single root-
have become invisible, yet that there is irrefragable evidence to
show that they once actually existed, and indeed are existing at
this moment, in a condition as real though as invisible to the
eye as air or electricity. Should we, I ask, under these
circumstances hesitate to call our imaginary plant or tree by a
single name, and to think of it as one person, merely upon the
score that the woody fibre [sic] was invisible? Should we not
esteem the common soul, memories and principles of growth which
are preserved between all the buds, no matter how widely they