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46 ANCIENT TIMES.
and he already foreshadowed that great theory of creation
which asserts that the development of organisms proceeds
from lower to higher forms, and that only the conformable
survive. He was of opinion that not only men and
brutes but plants also are endowed with souls; he busied
himself with the subject of the senses and with the act of
respiration which he sought to elucidate in a mechanical
way; and he regarded the labyrinth of the ear as the seat of
hearing. His contemporaries ANAXAGORAS of Klazomene,
and DIOGENES of Apollonia directed their attention chiefly
to anatomy. The former undertook the dissection of
animals* and noticed the lateral ventricles of the brain :
moreover he was the first to give utterance to the opinion—
raised into a dogmaf by later doctors—that the bile is the
cause of acute sickness. DlOGENES left behind him a
description of the vascular system which it must be confessed
contains numerous errors.^ HERAKLITOS saw in
the constant changes of form, in the everlasting mutations
of things, the individual nature of these. Like EMPEDOKLES
he ascribed a weighty influence upon the activities of the
organism to fire, the internal heat. His views hold a place
in the collection of dogmas belonging to the Hippokratic
school and for a' long time played an important part in
physiology and pathology. In a higher degree was this
the case with the theories of LEUKIPPOS and DEMOKRITOS.
The materialism which dominated their doctrine of atoms,
led to the investigation of nature,, as the only way which
promised results. DEMOKRiTOS§ devoted himself with
great zeal to anatomical investigations and appears to have
been very skilful in them for he was able to compose a
special treatise upon the structure of the chameleon.|| He
* PLUTARCH : Perikles, c. 6.
t Vide die Nach-Galen'sche Schrift liber die kritischen Tage in HIPPOKRATES
op. cit. T. ix, p. 300 et srq.
X ARISTOTELES: Hist. Animal, iii, 2.
§ ARISTOTELES: de generat. i, 2.—CICERO: Tusc.qufest. v, 39.
|| PLINIUS: Hist. Nat. xxviii, c. 29.