The ten parts or layers of the head are a commonplace of the anatomy of
the period, taken from Avicenna. We may illustrate the division by the
crude contemporary diagram of Fig. 11, which is improved in the later
drawing reproduced in Fig. 12.
Manfredi’s account of the brain itself is amplified from Mondino. The
division of this organ into three ventricles, each associated with
a corresponding division of the mental functions, was very familiar
to medical writers of the fifteenth century. The idea is found among
Western writers as early as St. Augustine (354-430), and is encountered
in the writings of Roger Bacon (1214-94). It had long been popularized
in mediaeval psychology by the writings of Albertus Magnus (1206-80).
The anatomical distinction is found in Haly Abbas, Avicenna, and
Rhazes, and in some of the best MSS. of the latter writer a rough
diagram of the ventricles is given.[188] These writers are all clearly
indebted to the anatomy of Galen,[189] but on the psychological
side Albertus Magnus probably drew mainly either from Ghazali[190]
(1059-1111), who in turn derived his inspiration from Nemesius (fourth
century) and Johannes Damascenus (died 756), or else from early
writers of the Salernitan tradition, such as Constantine[191] (eleventh
century), or Petrocello[192] (twelfth century), who drew largely on
Theophilus (seventh century).[193]
[Illustration: Fig. 13. From _Illustrissimi philosophi et theologi
domini Alberti magni compendiosum insigne ac perutile opus Philosophiae
naturalis_, Venice, 1496, showing the ventricles of the brain.]
This outline of a tripartite division of the brain and its cavities was
closely followed throughout the Middle Ages, as was also the curiously
naïve and excessively ‘materialistic’ psychology to which it gave rise,
and which Manfredi adopts. We illustrate his views of the relationship
of the different parts of the brain and their parallelism in mental
processes, from a series of diagrams extracted from contemporary works
(Figs. 13-18).
[Illustration: Fig. 14. Diagram of the senses, the humours, the
cerebral ventricles, and the intellectual faculties. MS. Sloane 2156,
folio 11 recto, in the British Museum, being a copy written in 1428 of
the _De Scientia Perpectiva_ of Roger Bacon]
[Illustration: Fig. 15. From K. Peyligk’s _Philosophiae naturalis
compendium_, Leipzig, 1489. Illustrating the general ideas on anatomy
current at the Renaissance.]
[Illustration: Fig. 16. The cerebral ventricles from above and from the
side. According to K. Peyligk, _Philosophiae naturalis compendium_,
Leipzig, 1489.]
[Illustration: Fig. 17. The localization of cerebral functions. From
the Italian edition of ‘Ketham’, _Fasciculus Medicinae_, Venice, 1493.]
[Illustration: Fig. 18. From G. Reisch, _Margarita philosophiae_,
Leipzig,? 1503. Diagram of the ventricles and the senses with their
relation to the intellectual processes according to the doctrine of the
Renaissance anatomists.]
The brain was regarded by mediaeval and early Renaissance anatomists
as having two channels of discharge through which the _phlegm_, the
especial product of this organ, could be evacuated when in excess.
One of these channels communicated with the anterior ventricle of the
brain and poured its secretion into the nose. It may be identified
with the _anterior colature_ or cribriform plate. The second, the
_lacuna_, led down from the second ventricle and poured its secretion
into the pharynx. It may be identified with the infundibulum, pituitary
body, and ‘cella turcica’. The term ‘pituitary’ which we still use is
derived from its supposed association with the ‘pituita’ or phlegm. At
an early date this process was connected with the four humours (Fig.
14). The rest of the description of the brain can be easily followed.
The comparison of the choroid plexus to a worm is very common. The
suggestion originated with Galen and was developed by the Arabians.