everal of these species,
by migrating into new countries and coming into competition with foreign
associates, might become modified; so that we must not overrate the
accuracy of organic change as a measure of time. During early periods of
the earth's history, when the forms of life were probably fewer and
simpler, the rate of change was probably slower; and at the first dawn of
life, when very few forms of the simplest structure existed, the rate of
change may have been slow in an extreme degree. The whole history of the
world, as at present known, although of a length quite incomprehensible by
us, will hereafter be recognised as a mere fragment of time, compared with
the ages which have elapsed since the first creature, the progenitor of
innumerable extinct and living descendants, was created.

In the distant future I see open fields for far more {489} important
researches. Psychology will be based on a new foundation, that of the
necessary acquirement of each mental power and capacity by gradation. Light
will be thrown on the origin of man and his history.

Authors of the highest eminence seem to be fully satisfied with the view
that each species has been independently created. To my mind it accords
better with what we know of the laws impressed on matter by the Creator,
that the production and extinction of the past and present inhabitants of
the world should have been due to secondary causes, like those determining
the birth and death of the individual. When I view all beings not as
special creations, but as the lineal descendants of some few beings which
lived long before the first bed of the Silurian system was deposited, they
seem to me to become ennobled. Judging from the past, we may safely infer
that not one living species will transmit its unaltered likeness to a
distant futurity. And of the species now living very few will transmit
progeny of any kind to a far distant futurity; for the manner in which all
organic beings are grouped, shows that the greater number of species of
each genus, and all the species of many genera, have left no descendants,
but have become utterly extinct. We can so far take a prophetic glance into
futurity as to foretel that it will be the common and widely-spread
species, belonging to the larger and dominant groups, which will ultimately
prevail and procreate new and dominant species. As all the living forms of
life are the lineal descendants of those which lived long before the
Si