actor and a heterozygote with respect to another.

HORMONES (chain), the secretions of various internal glands,
which are carried in the blood and have an important specific influence
on the growth and functioning of various parts of the body. Their exact
nature is not yet understood.

INBORN usually means germinal, as applied to a trait, and it is
so used in this book. Strictly speaking, however, any trait which
appears in a child at birth might be called inborn, and some writers,
particularly medical men, thus refer to traits acquired in prenatal
life. Because of this ambiguity the word should be carefully defined
when used, or avoided.

INHERENT (in stick), as used in this book, is synonymous with
germinal.

INDUCTION (in lead), a change brought about in the germ-plasm
with the effect of temporarily modifying the characters of an
individual produced from that germ-plasm; but not of changing in a
definite and permanent way any such germ-plasm and therefore any
individual inherited traits.

INNATE (inborn), synonymous with inborn.

LATENT (lie hidden), a term applied to traits or characters
whose factors exist in the germ-plasm of an individual, but which are
not visible in his body.

LAW, in natural science means a concise and comprehensive
description of an observed uniform sequence of events. It is thus quite
different from the law of jurists, who mean a rule laid down for the
guidance of an intelligent being, by an intelligent being having power
over him.

MENDELISM, a collection of laws of heredity (see Appendix D)
so-called after the discoverer of the first of them to become known;
also the analytical study of heredity with a view to learning the
constitution of the germ-cells of animals and plants.

MENDELIZE, to follow Mendel's laws of inheritance.

MORES (customs), the approved customs or unwritten laws of a
people; the conventions of society; popular usage or folk-ways which are
reputable.

MUTATION (change), has now two accepted meanings: (1) a
profound change in the germ-plasm of an organism such as will produce
numerous changes in its progeny; and (2) a discontinuous heritable
change in a Mendelian factor. It is used in the first sense by De Vries
and other "mutationists" and in the second sense by Morgan and other
Mendelists; confusion has arisen from failure to note the difference in
usage.

NORMAL CURVE, the curve of distribution of variations of
something whose variations are due to a