hagus, the fallopian tubes to the intestine, and so on.

The vertebral theory of the skull took its origin from the same habit of
thought. As part of the wider idea of the metameric repetition of parts
it had some scientific worth, but the theory was pushed too far, and the
facts were twisted to suit it. Among annulate animals the theory of
repetition found ample scope; Oken was able to compare with justice the
jaws of crabs and insects with their other limbs, as Savigny did later
in a more scientific way. Among Vertebrates the application of the
theory of serial repetition was not so obvious, except in the case of
the vertebrae. Goethe seems to have been the first to hit upon the idea
that the skull is composed of a number of vertebrae, serially homologous
with those of the vertebral column. He tells us that the idea flashed
into his mind when contemplating in the Jewish cemetery at Venice a
dried sheep's skull. The discovery was made in 1790, but not published
till 1820.[154]

The idea seems to have been taught by Kielmeyer, one of the earliest of
the "philosophers of nature," but it was not published by him.

In a book (_Cours d'Etudes medicales_), published in 1803, Burdin
assimilated the skull to the vertebral column.

Oken, in an inaugural dissertation (Programm) _Ueber die Bedeutung der
Schaedelknochen_,[155] published in 1807, gave to the theory its necessary
development. Autenrieth, also in 1807,[156] distinguishing separate
ganglia in the brain, was not far from the hypothesis that each of these
ganglia must have its separate vertebra.

In 1808 Dumeril read a paper to the Academie des Sciences in which he
compared the skull to a gigantic vertebra, basing his hypothesis on the
similarity existing between the crests and depressions on the hinder
part of the skull and those on the posterior surfaces of the vertebrae.

After Oken's work the vertebral theory was taken up generally by both
the German and the French anatomists. Spix published in 1815 a large
volume on the skull, entitled _Cephalogenesis_, distinguishing (as Oken
did at first) three cranial vertebrae. Bojanus in his _Anatome testudinis
europaeae_ (1819), and in a series of papers in _Isis_ (1817-1819, and
1821) established the existence of a fourth cranial vertebra, and this
was accepted by Oken in the later editions of his _Lehrbuch_. Meckel and
Carus among the Germans, de Blainville and E. Geoffroy among the French,
contributed to the developme