nature; physiological signification of twinship; replies to
a circular of inquiries; eighty cases of close resemblance
between twins; the points in which their resemblance was
closest; extracts from the replies; interchangeableness of
likeness; cases of similar forms of insanity in both twins;
their tastes and dispositions; causes of growing dissimilarity
mainly referred to illness; partly to gradual development of
latent elements of dissimilarity; effect of childish illnesses
in permanently checking growth of head; parallel lives and
deaths among twins; necessitarianism; twenty cases of great
dissimilarity; extracts from the replies; evidence of slight
exaggeration; education is almost powerless to diminish
natural difference of character; simile of sticks floating
down a brook; depth of impressions made in childhood;
they are partly due to the ease with which parents and
children understand one another; cuckoos forget the teachings
of their foster-mothers.

DOMESTICATION OF ANIMALS

Alternative hypotheses of the prehistoric process of
domestication; savages rear captive animals; instances in
North America; South America; North Africa; Equatorial
Africa; South Africa; Australia; New Guinea Group;
Polynesia; ancient Syria. Sacred animals; menageries
and shows in amphitheatres; instances in ancient Egypt;
Assyria; Rome; Mexico; Peru; Syria and Greece.
Domestication is only possible when the species has certain
natural faculties, viz.--great hardiness; fondness for man;
desire of comfort; usefulness to man; fertility; being easy