se which
Lamarck has cited to support his first law [pp. 303, 346]; the only
point which is open to discussion is the extent of the changes which
an organ may undergo, through the use it is put to by the animal. It
is a simple question of measurement. The possibility of the creation
of an organ in consequence of external stimuli is itself a matter
which deserves to be studied, and which we have no right to reject
without investigation, without observations, or to treat as a
ridiculous dream; Lamarck would doubtless have made it more readily
accepted, if he had not thought it well to pass over the
intermediate steps by means of wants. It is incontestable that by
lack of exercise organs atrophy and disappear."

Finally, says Perrier: "Without doubt the real mechanism of the
improvement (_perfectionnement_) of organisms has escaped him
[Lamarck], but neither has Darwin explained it. The law of natural
selection is not the indication of a process of transformation of
animals; it is the expression of the total results. It states these
results without showing us how they have been brought about. We
indeed see that it tends to the preservation of the most perfect
organisms; but Darwin does not show us how the organisms themselves
originated. This is a void which we have only during these later
years tried to fill" (p. 90).

Dr. J. A. Jeffries, author of an essay "On the Epidermal System of
Birds," in a later paper[252] thus frankly expresses his views as to the
relations of natural selection to the Lamarckian factors. Referring to
Darwin's case of the leg bones of domestic ducks compared with those of
wild ducks, and the atrophy of disused organs, he adds:

"In this case, as with most of Lamarck's laws, Darwin has taken them
to himself wherever natural selection, sexual selection, and the
like have fallen to the ground.

"Darwin's natural selection does not depend, as is popularly
supposed, on direct proof, but is adduced as an hypothesis which
gains its strength from being compatible with so many facts of
correlation between an organism and its surroundings. Yet the same
writer who considers natural selection proved will call for positive
experimental proof of Lamarck's theory, and refuse to accept its
general compatibility with the facts as support. Almost any case
where natural selection is held to act by virtue of advantage gained
by use of a part is eq