fig. 17), called respectively the "glosso-kinæsthetic" (sense of movement
of tongue) and the "cheiro-kinæsthetic" (sense of movement of hand) centres.
Now a person may become hemiplegic and lose his speech owing either to the
blood clotting in a diseased vessel, or to detachment of a small clot from
the heart, which, swept into the circulation, may plug one of the arteries
of the brain. The arteries branch and supply different regions,
consequently a limited portion of the great brain may undergo destruction,
giving rise to certain localising symptoms, according to the situation of
the area which has been deprived of its blood supply. Upon the death of the
patient, a correlation of the symptoms observed during life and the loss of
brain substance found at the _post-mortem_ examination has enabled
neurologists to associate certain parts of the brain surface with certain
functions; but M. Marie very rightly says: None of the older observations
by Broca and others can be accepted because they were not examined by
methods which would reveal the extent of the damage; the only cases which
should be considered as scientifically reliable are those in which a
careful examination by sections and microscopic investigation have
determined how far subcortical structures and systems of fibres uniting
various parts of the cortex in the speech zone have been damaged. Marie
maintains that the speech zone cannot be separated into these several
centres, and that destruction of Broca's convolution does not cause loss of
speech (_vide_ figs. 16, 17). There are at present two camps--those who
maintain the older views of precise cortical centres, and those who follow
Marie and insist upon a revision.

Herbert Spencer says that "our intellectual operations are indeed mostly
confined to the auditory feelings as integrated into words and the visual
feelings as integrated into ideas of objects, their relations and their
motions."