rently offered to support a belief in the inheritance
of acquired characters is tested by the application of these
"misunderstandings," it will at once be found that most of it
disappears; that it can be thrown out of court without further
formality. The Lamarckian doctrine is now held mainly by persons who
have either lacked training in the evaluation of evidence, or have never
examined critically the assumptions on which they proceed. Medical men
and breeders of plants or animals are to a large extent believers in
Lamarckism, but the evidence (if any) on which they rely is always
susceptible of explanation in a more reasonable way. It must not be
forgotten that some of the ablest intellects in the world have been
assidously engaged in getting at the truth in the case, during the last
half-century; and it is certainly worthy of consideration that not in a
single case has the transmission of an acquired body character ever
been proved beyond dispute. Those who still hold a belief in it (and it
is fair to say that some men of real ability are among that number) too
often do so, it is to be feared, because it is necessary for the support
of some theoretical doctrine which they have formulated. Certainly there
are few men who can say that they have carefully examined the evidence
in the case, and accept Lamarckism because the evidence forces them to
do so. It will be interesting to review the various classes of alleged
evidence, though we can cite only a few cases from the great number
available (most of them, however, dealing with plants or lower animals).

Nearly all the evidence adduced can be put in one of these four classes:

(1) Mutilations.
(2) Diseases.
(3) Results of use or disuse.
(4) Physico-chemical effects of environment.

The case in regard to mutilations is particularly clear cut and leaves
little room for doubt. The noses and ears of oriental women have been
pierced for generations without number, yet girls are still born with
these parts entire. Circumcision offers another test case. The evidence
of laboratory experiments (amputation of tails) shows no inheritance. It
may be said without hesitation that mutilations are not heritable, no
matter how many generations undergo them.

(2) The transmissibility of acquired diseases is a question involved in
more of a haze of ignorance and loose thinking. It is particularly
frequent to see cases of uterine infection offered as cases of the
inherita