Freiburger historische Bestände - digital

236

Cunningham Memoirs.

Wernicke,* in discussing the significance of these intraparietal deep
gyri, has come to the conclusion that they are peculiar to the human brain,
and to this statement Mihalkovicsf adds the following remarks :—" The
more strongly expressed, and the more superficial these interparietal bridges
are, the more highly developed is the brain, and vice versa. In the apes the
interparietal furrow is not bridged over." The latter part of this assertion
has also been repeated by Rudinger,J who says : u In no primate brain
does the sagittal portion of the interparietal furrow become bridged over."
This is not correct, however, because deep annectant gyri may be found
in the course of the intraparietal sulcus of the chimpanzee. In two hemi
spheres, taken from the same animal (fig. 36, p. 104), a strongly-marked
bridge interrupted the junction between the ramus horizontalis and the
postcentral sulcus, whilst in two other hemispheres (fig. 35, p. 103) a
very distinct deep gyrus indicated the point of union between the ramus
occipitalis and the ramus horizontalis. Further, in the baboon it is by no
means infrequent to find a deep annectant gyrus at the latter point.

VIII. The Intraparietal Angle.—Under this heading I purpose dealing
with the inclination of the sagittal part of the intraparietal sulcus (i e. the
combined horizontal and occipital rami), and establishing the angle at which
its hinder end, when produced, intersects another line corresponding to the
mesial plane prolonged backwards. This leads us to consider the work which
Rudinger has done in the same direction. This author has endeavoured to
prove that the inclination of the sagittal portion of the sulcus differs according
to sex, race, and the intellectual capacity of the individual, and that
we can recognize by this feature a regular gradation from the low apes up
through the anthropoid apes, the human female, the human male, until we
finally arrive at those individuals possessed of exceptional mental endowments
. He says : "No furrow and no convolution influences the position

* " Das Urwindungssystem des menschlichen Gehirns," Archiv fur Psychiatrie," Band vi.
f Entwicklungsgeschichte des Gehirns, Leipzig, 1877, p. 154.

\ "EinBeitrag zur Anatomie der Affenspalte und der Interparietalfurche beim Menschen
nach Race, Geschlecht und Individuality."—Beitrage zur Anatomie und Embryologie als
Festgabe, Jacob Henle, von seinen Schulern, Bonn, 1882.