Heritage (L. heres, heir), all that is inherited by an individual.
Heterozygote (Gr. heteros, other; zygon, yolk), an individual produced through the union of germ-cells which are unlike in one or more determiners. Adjective, heterozygous.
Homozygote (Gr. homos, same; zygon, yolk), an individual produced through the union of germ-cells which are alike in determiners. Adjective, homozygous.
Hybrid (L. hybrida, mongrel), the offspring of parents which differ in one or more characters.
Identical Twins, twins which show identical inborn characters, both having come presumably from the same ovum.
Idiot (Gr. idios, peculiar, private), defined, [p. 244].
Imbecile (L. imbecillis, weak), defined, [p. 244].
Inheritance (L. in, in; heres, heir), the sum of all characters which are transmitted by the germ-cells from generation to generation.
Inhibitor (L. in, in; habeo, hold, have), that which checks or restrains.
Instinct (L. in, in; stingno, prick), defined, [p. 203].