certain that the ordinary succession by generation
has never once been broken, and that no cataclysm has desolated the
whole world. Hence, we may look with some confidence to a secure future
of great length. And as natural selection works solely by and for the
good of each being, all corporeal and mental endowments will tend to
progress towards perfection.

It is interesting to contemplate a tangled bank, clothed with many
plants of many kinds, with birds singing on the bushes, with various
insects flitting about, and with worms crawling through the damp earth,
and to reflect that these elaborately constructed forms, so different
from each other, and dependent upon each other in so complex a manner,
have all been produced by laws acting around us. These laws, taken in
the largest sense, being Growth with reproduction; Inheritance which is
almost implied by reproduction; Variability from the indirect and direct
action of the conditions of life, and from use and disuse; a Ratio of
Increase so high as to lead to a Struggle for Life, and as a consequence
to Natural Selection, entailing Divergence of Character and the
Extinction of less improved forms. Thus, from the war of nature, from
famine and death, the most exalted object which we are capable of
conceiving, namely, the production of the higher animals, directly
follows. There is grandeur in this view of life, with its several
powers, having been originally breathed by the Creator into a few forms
or into one; and that, whilst this planet has gone circling on according
to the fixed law of gravity, from so simple a beginning endless forms
most beautiful and most wonderful have been, and are being evolved.

GLOSSARY OF THE PRINCIPAL SCIENTIFIC TERMS USED IN THE PRESENT VOLUME.

(I am indebted to the kindness of Mr. W.S. Dallas for this Glossary,
which has been given because several readers have complained to me
that some of the terms used were unintelligible to them. Mr. Dallas has
endeavoured to give the explanations of the terms in as popular a form
as possible.)

ABERRANT.--Forms or groups of animals or plants which deviate in
important characters from their nearest allies, so as not to be easily
included in the same group with them, are said to be aberrant.

ABERRATION (in Optics).--In the refraction of light by a convex lens the
rays passing through different parts of the lens are brought to a focus
at slightly different distances--this is called SPHERICAL ABER