ity on their offspring, thereby
preventing their being confounded together, and pointing out that a
multitude of distinct types must have been created in the beginning, and
must have remained pure and uncorrupted to this day.

Relying on this general law, he endeavors to solve each difficult
problem by direct experiment, until he is again astounded by the
phenomenon of a prolific hybrid, and still more by an example of a
hybrid perpetuating itself throughout several generations in the
vegetable world. He then feels himself reduced to the dilemma of
choosing between two alternatives; either to reject the test, or to
declare that the two species, from the union of which the fruitful
progeny has sprung, were mere varieties. If he prefer the latter, he is
compelled to question the reality of the distinctness of all other
supposed species which differ no more than the parents of such prolific
hybrids; for although he may not be enabled immediately to procure, in
all such instances, a fruitful offspring; yet experiments show, that
after repeated failures, the union of two recognized species may at
last, under very favorable circumstances, give birth to a fertile
progeny. Such circumstances, therefore, the naturalist may conceive to
have occurred again and again, in the course of a great lapse of ages.

His first opinions are now fairly unsettled, and every stay at which he
has caught has given way one after another; he is in danger of falling
into any new and visionary doctrine which may be presented to him; for
he now regards every part of the animate creation as void of stability,
and in a state of continual flux. In this mood he encounters the
Geologist, who relates to him how there have been endless vicissitudes
in the shape and structure of organic beings in former ages--how the
approach to the present system of things has been gradual--that there
has been a progressive development of organization subservient to the
purposes of life, from the most simple to the most complex state--that
the appearance of man is the last phenomenon in a long succession of
events--and, finally, that a series of physical revolutions can be
traced in the inorganic world, coeval and co-extensive with those of
organic nature.

These views seem immediately to confirm all his preconceived doubts as
to the stability of the specific character, and he begins to think there
may exist an inseparable connection between a series of changes in the
ina