ait every jot
and tittle of evidence in such a case as this. They discern the drift of
a fact here, a disclosure there, and with both wisdom and boldness
assume that what they see is but a promise of what shall duly be
revealed. Thus it was that Darwin early in his studies became convinced
of the truth of organic evolution: the labours of a lifetime of all but
superhuman effort, a judicial faculty never exceeded among men, served
only to confirm his confidence that all the varied forms of life upon
earth have come to be what they are through an intelligible process,
mainly by "natural selection."

The present volume offers from the classic pages of Darwin his summary
of the argument of "The Origin of Species," his account of how that book
came to be written, and his recapitulation of "The Descent of Man." All
this affords a supreme lesson as to the value of observation with a
purpose. When Darwin was confronted with an organ or trait which puzzled
him, he was wont to ask, What use can it have had? And always the answer
was that every new peculiarity of plant, or beast, is seized upon and
held whenever it confers advantage in the unceasing conflict for place
and food. No hue of scale or plume, no curve of beak or note of song,
but has served a purpose in the plot of life, or advanced the action in
a drama where the penalty for failure is extinction.

As Charles Darwin stood first among the naturalists of the nineteenth
century, his advocacy of evolution soon wrought conviction among the
thinkers competent to follow his evidence and weigh his arguments. The
opposition to his theories though short was sharp, and here he found a
lieutenant of unflinching courage, of the highest expository power, in
Professor Huxley. This great teacher came to America in 1876, and
discoursed on the ancestry of the horse, as disclosed in fossils then
recently discovered in the Far West, maintaining that they afforded
unimpeachable proof of organic evolution. His principal lecture is here
given.

In a remarkable field of "natural selection" Bates, Wallace and Poulton
have explained the value of "mimicry" as an aid to beasts, birds,
insects, as they elude their enemies or lie unsuspected on the watch for
prey. The resemblances thus worked out through successive generations
attest the astonishing plasticity of bodily forms, a plasticity which
would be incredible were not its evidence under our eyes in every
quarter of the globe. Insects have