of evolution, as was early pointed out
by the late Professor Fleeming Jenkin and by Mr. Herbert Spencer,
that variations should be supposed to have a definite and persistent
principle underlying them, which shall tend to engender similar and
simultaneous modification, however small, in the vast majority of
individuals composing any species. The existence of such a
principle and its permanence is the only thing that can be supposed
capable of acting as rudder and compass to the accumulation of
variations, and of making it hold steadily on one course for each
species, till eventually many havens, far remote from one another,
are safely reached.

It is obvious that the having fatally impaired the theory of his
predecessors could not warrant Mr. Darwin in claiming, as he most
fatuously did, the theory of evolution. That he is still generally
believed to have been the originator of this theory is due to the
fact that he claimed it, and that a powerful literary backing at
once came forward to support him. It seems at first sight
improbable that those who too zealously urged his claims were
unaware that so much had been written on the subject, but when we
find even Mr. Wallace himself as profoundly ignorant on this subject
as he still either is, or affects to be, there is no limit
assignable to the ignorance or affected ignorance of the kind of
biologists who would write reviews in leading journals thirty years
ago. Mr. Wallace writes:--

"A few great naturalists, struck by the very slight difference
between many of these species, and the numerous links that exist
between the most different forms of animals and plants, and also
observing that a great many species do vary considerably in their
forms, colours and habits, conceived the idea that they might be all
produced one from the other. The most eminent of these writers was
a great French naturalist, Lamarck, who published an elaborate work,
the Philosophie Zoologique, in which he endeavoured to prove that
all animals whatever are descended from other species of animals.
He attributed the change of species chiefly to the effect of changes
in the conditions of life--such as climate, food, etc.; and
especially to the desires and efforts of the animals themselves to
improve their condition, leading to a modification of form or size
in certain parts, owing to the well-known physiological law that all
organs are strengthened by constant use, while they are weakened or
e