Freiburger historische Bestände – digital

8

Cunningham Memoirs.

the manner in which these early infoldings of the hemisphere wall disappear
is of some interest. We shall use his own words :—" But upon this period
another supervenes in which these convolutions, as well as their outer and
inner surfaces, grow into each other, so that the surface of the brain,
both inside and outside, again becomes smooth." And he considers that
this process of obliteration may be regarded as affording a means by which
the wall of the ventricle is thickened, and also by which the white substance
is increased in quantity.*

In the following year (1816) Friedrich Tiedemannf figured the transitory
fissures for the first time. He failed however to recognize their
temporary character, and considered that they represent the earlier
conditions of the permanent sulci.

Schmidt,% in 1862, contributed an excellent Paper on the early development
of the brain. He describes the temporary furrows and is satisfied
that they are in course of time obliterated. He says :—" These folds take
no share whatsoever in the formation of the real convolutions. Without
doubt they are produced by the strong growth of the hemisphere in the
longitudinal direction... a view which has also been previously expressed
by others." One point of high importance he adds: viz. that, although he
has failed to discover them in the embryos of the sheep, ox, and pig, he
believes that he has seen faint traces of them in the brain of the early cat-
embryo.

Ecker,§ His,|[ v. Kolliker,^" Mihalkovics,** and other German authors,
have likewise taken notice of the temporary furrows, although they have as
a rule dealt with them briefly, and have not made a serious attempt to
unravel the part which they play in the process of brain development. It
is but right to mention, however, that Bichterff has given an admirable
* Deutsches Archiv f. Physiol., Halle und Berlin, Bel. i., 1815.

| Anatomie unci Bilclungsgeschichte des Gehirns im Ecetus des Menschen, Niirnberg, 1816.
J "Beitrage zur Entwicklungsgeschichte des Gehirns," Zeitsch. f. "Wiss. Zool., Bd. si.
§ " Zur Entwicklungsgeschichte der lurch en und Windungen der Grosshirnhemispharen im
Foetus des Menschen," Archiv f. Anthrop.,\Dritter Band, Drittes und Viertes Heft, 1869.
|| Unsere Kb'rperform, Leipzig, 1875.

*[[ Entwicklungsgeschichte des Menschen und der hoheren Thiere, 1879.
** Entwicklungsgeschichte des Gehirns, 18.

If "Ueber die Entstehung der Grosshirnwindungen," Yirchow's Archiv, Berlin, 1887.