In 1810 Gall published the neuroanatomist's manual Anatomie,
correlating on three variations in character with variations in external craniological
signs, an approach that depended critical assumptions: that the size
Line and shape of the cranium reflected the size and shape of the underlying portions
(5) of the cerebrum, that mental abilities were innate and fixed, and that the
relative level of development of an innate ability was a reflection of the
inherited size of its cerebral organ．On these assumptions, an observed
correspondence between a particularly well-developed ability and a particularly
prominent area of the cranium could be interpreted as evidence of the functional
(10) localization of that ability in the correlative portion of the cerebrum.
Gall's approach was abandoned in favor of experiment, his conception of
fixed, innate faculties replaced by a dynamic, evolutionary view of mental
development, and his pivotal assumption concerning the relationship of brain to
cranial conformation rejected, but we cannot overestimate his importance in
(15) linking brain activity to specific cerebral anatomy．Gail's assumptions may have
been flawed, but not his scientific logic or rigorous empiricism．In postulating a
set of innate, mental traits inherited through the cerebral organ, Gall admitted
differences in aptitude among individuals and between species and thus deviated
from the tabula rasa view of Condillac.
(20) Even Gall's opponent, Flourens, was willing to admit that it was Gall who
established that the brain serves as the organ of mind．In other respects,
however, Flourens was highly critical of Gall, and soon provided the first
experimental demonstration of localization of function in the brain by employing
ablation to localize a motor center in the front of the brain and motor
(25) coordination in its rear．Although his treatment of sensation was still rather
confused, Flourens articulated a clear distinction between sensation and
perception and localized sensory function within the brain．But with respect to
the cerebrum, a successive slicing through the brain hemispheres produced
diffuse damage to all of the higher mental functions—to perception, intellect,
(30) and will—with the amount of damage varying only with the extent and not the
location of the lesion．Flourens thus concluded that while sensory-motor
functions are differentiated and localized sub-cortically, higher mental functions
such as perception, volition, and intellect are spread throughout the cerebrum,
operating together with the entire cerebrum functioning in a unitary fashion as
(35) their exclusive seat.
As Gall himself observed, ablation was not a method well-suited to the
discovery of cortical localization．Joined to a strong philosophical belief in a
unitary soul and an indivisible mind and an uncritical willingness to generalize
results from lower organisms to humans, Flourens's results led him to
(40) challenge Gall's efforts at localization and to formulate a theory of cerebral
homogeneity wherein, the cerebrum was the organ of a unitary mind which
could not be functionally differentiated to the extent Gall suggested.