ikely to be further sanctioned by
much that remains to be known, that the first step was _an
advance, under favor of peculiar circumstances, from the
simplest forms of being to the next more complicated, and this
through the medium, of the ordinary process of generation._"

And further:--

"_That the simplest and most primitive type, under a law to
which that of like production is subordinate, gave birth to the
type next above it; that this again produced the next higher,
and so on to the very highest_, the stages of advance being in
all cases very small, namely, from one species to another; so
that the phenomenon has always been of a simple and modest
character."

In a Sequel which the author wrote, in answer to the numerous attacks
made upon him, he has the following:--

"The probable fact is, that the modification takes place in an
offshoot of the original tribe, which has removed into a
different set of circumstances, these circumstances being the
cause of the change; thus there is no need to presume that the
original tribe is at all affected by any such modification."

The author thus supposes that the variations among animals were
periodical and sudden, the results of some peculiar impetus given at
special periods. Later knowledge--the study of nature by the light of
greater experience--has exposed many errors in this work. Its crudities
have been made apparent; but the thought which pervaded it was
intrinsically right. The last passage quoted above foreshadows the more
elaborate speculations of the later philosopher.

In 1859 appeared Darwin's work, "On the Origin of Species, by Means of
Natural Selection, or the Preservation of Favored Races in the Struggle
for Life." Like its predecessors, it was a firebrand thrown into the
scientific camp. Like his predecessors, the author drew down obloquy and
anathemas from the clergy, sarcasm and vituperation from the laity, and
a host of replies from writers of all grades. Like his predecessor, the
author of the "Vestiges," he might have said, in the words of Agassiz:--

"The history of the sciences is present to tell us that there
are few of the great truths now recognized which have not been
treated as chimerical and blasphemous before they were
demonstrated."

Darwin, as he himself tells us in his Preface, spent twenty years in a
patient, laborious study of natu