l
senses; obstacles are avoided, and a variety of directions pursued. Yet
still the actions are not intelligent, only instinctive. The general
conclusion therefore is, that the cephalic ganglia are of a higher order
than the ventral, the latter being simply mechanical, the former
instinctive; but thus far there is no trace of intelligence.

[Sidenote: Nervous anatomy of vertebrates, as man.] In man these typical
parts are all present, and discharge the functions specified. His spinal
cord answers to the ventral cord of the articulates. It has its lateral
communications in the same way, and each segmental portion presents the
same reflex action. Toward its upper part it dilates to form the medulla
oblongata, sending forth nerves for respiration and deglutition.
[Sidenote: Their automatic apparatus.] Of these the action is still
reflex, as is proved by the involuntary movements of respiration and
deglutition. A portion of food being placed in the pharynx, contraction
instantly occurs, the will having no kind of control over the act of
swallowing. [Sidenote: Their instinctive apparatus.] Above or in front
of this enlargement is a series of ganglia, to which converge the nerves
of special sense--of hearing, sight, smell; these are, therefore, the
equivalents of the cephalic ganglia of insects, their function being
also the same. In the lowest vertebrates, as in the amphioxus, the
nervous system consists of nothing more. It may therefore be said to
have only two parts--the cord and the sensory ganglia, and to have two
functions--the automatic, attributable to the former, and the
instinctive, attributable to the latter.

[Sidenote: Their intellectual apparatus.] But as we advance from the low
vertebrates upward in the animal scale, we begin to detect new organs;
on the medulla oblongata a cerebellum, and on the sensory ganglia a
cerebrum. From this moment the animal displays reasoning powers, its
intelligence becoming more strikingly marked as the development of the
new organs is greater.

[Sidenote: Functions of the brain.] It remains to determine with
exactness the function of one of these new parts, the cerebrum; the
other portion, the cerebellum, being of minor interest, and connected,
probably, with the locomotive apparatus. For the same reason it is
unnecessary to speak of the sympathetic nerve, since it belongs to the
apparatus of organic life. Confining our attention, therefore, to the
true brain, or cerebrum, we s