strative case
of neuter insects, against the well-known doctrine of inherited habit, as
advanced by Lamarck."--["Origin of Species," ed. 1872, p. 283.]

I am not aware that Lamarck advanced the doctrine that instinct is
inherited habit, but he may have done so in some work that I have not
seen.

It is true, as I have more than once pointed out, that in the later
editions of the "Origin of Species" it is no longer "the _most_ serious"
error to refer instincts generally to inherited habit, but it still
remains "a serious error," and this slight relaxation of severity does
not warrant Professor Weismann in ascribing to Mr. Darwin an opinion
which he emphatically condemned. His tone, however, is so offhand, that
those who have little acquaintance with the literature of evolution would
hardly guess that he is not much better informed on this subject than
themselves.

Returning to the inheritance of acquired characters, Professor Weismann
says that this has never been proved either by means of direct
observation or by experiment. "It must be admitted," he writes, "that
there are in existence numerous descriptions of cases which tend to prove
that such mutilations as the loss of fingers, the scars of wounds, &c.,
are inherited by the offspring, but in these descriptions the previous
history is invariably obscure, and hence the evidence loses all
scientific value."

The experiments of M. Brown-Sequard throw so much light upon the
question at issue that I will quote at some length from the summary given
by Mr. Darwin in his "Variation of Animals and Plants under
Domestication." {34} Mr. Darwin writes:--

"With respect to the inheritance of structures mutilated by injuries or
altered by disease, it was until lately difficult to come to any definite
conclusion." [Then follow several cases in which mutilations practised
for many generations are not found to be transmitted.] "Notwithstanding,"
continues Mr. Darwin, "the above several negative cases, we now possess
conclusive evidence that the effects of operations are sometimes
inherited. Dr. Brown-Sequard gives the following summary of his
observations on guinea-pigs, and this summary is so important that I will
quote the whole:--

"'1st. Appearance of epilepsy in animals born of parents having been
rendered epileptic by an injury to the spinal cord.

"'2nd. Appearance of epilepsy also in animals born of parents having
been rendered epileptic by the section of the