lled animals (crabs, etc.); (3) insects and their allies
(including various forms, such as spiders and centipedes, which the
modern classifier prefers to place by themselves); (4) hard-shelled
animals (clams, oysters, snails, etc.); (5) a conglomerate group of
marine forms, including star-fish, sea-urchins, and various anomalous
forms that were regarded as linking the animal to the vegetable worlds.
This classification of the lower forms of animal life continued in vogue
until Cuvier substituted for it his famous grouping into articulates,
mollusks, and radiates; which grouping in turn was in part superseded
later in the nineteenth century.

What Aristotle did for the animal kingdom his pupil, Theophrastus, did
in some measure for the vegetable kingdom. Theophrastus, however, was
much less a classifier than his master, and his work on botany, called
The Natural History of Development, pays comparatively slight attention
to theoretical questions. It deals largely with such practicalities
as the making of charcoal, of pitch, and of resin, and the effects
of various plants on the animal organism when taken as foods or as
medicines. In this regard the work of Theophrastus, is more nearly akin
to the natural history of the famous Roman compiler, Pliny. It remained,
however, throughout antiquity as the most important work on its subject,
and it entitles Theophrastus to be called the "father of botany."
Theophrastus deals also with the mineral kingdom after much the same
fashion, and here again his work is the most notable that was produced
in antiquity.

IX. GREEK SCIENCE OF THE ALEXANDRIAN OR HELLENISTIC PERIOD

We are entering now upon the most important scientific epoch of
antiquity. When Aristotle and Theophrastus passed from the scene, Athens
ceased to be in any sense the scientific centre of the world. That
city still retained its reminiscent glory, and cannot be ignored in the
history of culture, but no great scientific leader was ever again to
be born or to take up his permanent abode within the confines of Greece
proper. With almost cataclysmic suddenness, a new intellectual centre
appeared on the south shore of the Mediterranean. This was the city
of Alexandria, a city which Alexander the Great had founded during his
brief visit to Egypt, and which became the capital of Ptolemy Soter when
he chose Egypt as his portion of the dismembered empire of the great
Macedonian. Ptolemy had been with his master in the