intimately interwoven in the development of language and human
intelligence?

What has determined the predominance of the left hemisphere in speech? I
can find no adequate anatomical explanation. There is no difference in
weight of the two hemispheres in normal brains. Moreover, I am unable to
subscribe to the opinion that there is any evidence to show that the left
hemisphere receives a larger supply of blood than the right. Another theory
advanced to explain localisation of speech and right-handedness in the left
hemisphere is that the heavier organs, lung and liver, being on the right
side have determined a mechanical advantage which has led to
right-handedness in the great majority of people. This theory has, however,
been disposed of by the fact that cases in which there has been a complete
transposition of the viscera have not been left-handed in a larger
proportion of cases. The great majority of people, modern and ancient,
civilised and uncivilised, use the right hand by preference. Even graphic
representations on the sun-baked clay records of Assyria, and the drawings
on rocks, tusks, and horns of animals of the flint-weapon men of
prehistoric times show that man was then right-handed. There is a
difference of opinion whether anthropoid apes use the right hand in
preference to the left. Professor Cunningham, who made a special study of
this subject, asserts that they use either hand indifferently; so also does
the infant at first, and the idiot in a considerable number of cases. Then
why should man, even primitive, have chosen the right hand as the
instrument of the mind? Seeing that there is no apparent anatomical reason,
we may ask ourselves the question: Is it the result of an acquired useful
habit to which anatomical conditions may subsequently have contributed as a
co-efficient? Primitive man depended largely upon gesture language, and the
placing of the hand over the heart is universally understood to signify
love and fidelity. Uneducated deaf mutes, whose only means of communicating