lobes were found to be damaged by disease. A great controversy ensued in
France; popular imagination was stirred up especially in the republic by
the doctrine of Gall, which was an attempt to materialise and localise
psychic processes. Unfortunately Gall's imagination, encouraged by a
widespread wave of popular sympathy, overstepped his judgment and launched
him into speculative hypotheses unsupported by facts. His doctrine of
Phrenology was shown to be absolutely illogical; consequently it was
forgotten that he was the pioneer of cerebral localisation.




SPEECH AND RIGHT-HANDEDNESS


The next step in Cerebral Localisation was made by a French physician, Marc
Dax, who first observed that disease of the left half of the cerebrum
producing paralysis of the right half of the body (right hemiplegia) was
associated with loss of articulate speech. This observation led to the
establishment of a most important fact in connection with speech, viz. that
right-handed people use their left cerebral hemisphere as the executive
portion of the brain in speech. Subsequently it was shown that when
left-handed people were paralysed on the left side by disease of the right
hemisphere, they lost their powers of speech. But the great majority of
people are born right-handed, consequently the right hand being especially
the instrument of the mind in the majority of people, the left hemisphere
is the leading hemisphere; and since probably specialisation of function of
the right hand (dexterity) has been so closely associated with that other
instrument of the mind, the vocal instrument of articulate speech, the two
have now become inseparable; for are not graphic signs and verbal signs