development any one of the
inborn characters of an individual is modified by some occurrence, the
change thus produced is known as an acquired character, or, shortly,
as an acquirement.

"Thus all the effects of exercise are acquirements; for example the
enlargement which exercise causes in muscles. The effects of lack of
exercise are also acquirements; for example, the wasting of a disused
muscle.

"The effects of injury are acquirements; for example, the changes in a
diseased lung or injured arm. Every modification of the mind is also an
acquirement; for example, everything stored within the memory.

"If a man be blinded by accident or disease, his blindness is acquired.
But if he comes into the world blind, if he be blind by nature, his
blindness is inborn. If a son be naturally smaller than his father, then
his inferiority of size is inborn; but if his growth be stunted by ill
health or lack of nourishment or exercise, his inferiority is acquired.

"Lamarck held, as people in all ages have held, that characters acquired
by parents are also transmissible to some extent, and that evolution
results from their accentuation during succeeding generations. _Lamarck's
theory is rejected totally by the modern followers of Darwin_.

"Ten thousand men might break their fingers, yet among their offspring
not one might have a crooked finger. Consider on the other hand for how
many generations women have bored their ears and noses in India. Yet
when is a girl born with ears and nose already pierced? For how many
generations have we amputated the tails of terriers, and yet their
tails are no shorter. It will then be perceived how overwhelming is the
case against the doctrine of the transmission of acquirements.

"The general question of the transmission of acquirements is too big
and too abstruse to be treated adequately here. Two arguments more I
may use, however, partly because they have not been developed, to my
knowledge, by other writers, and partly because they seem to me
well-nigh decisive. The more than normal development of the
blacksmith's arm is rightfully called an acquired trait, since it
arises from exercise, from use, not from germinal conditions. But no
infant's arm develops into an ordinary adult arm without exercise
similar in kind to that which develops the blacksmith's arm, though
less in degree.

"Every single thing contained within the memory of man, every single
word of a language, for instance, is