15. Enumerate the different agencies through which the brain and spinal
cord are protected.
16. What cranial nerves contain afferent fibers? What ones contain
efferent fibers? What ones contain both afferent and efferent fibers?
17. In what respects is the nervous system similar to a system of
telephony? In what respects is it different?
PRACTICAL WORK
Examine a model of the brain, identifying the different divisions and
noting the position and relative size of the different parts (Fig. 137).
Observe the convolutions of the cerebrum and compare these with the
parallel ridges of the cerebellum. If the model is dissectible, study the
arrangement of the cell-bodies (gray matter) and the distribution of the
fiber bundles (white matter). Note the connection of the cranial nerves
with the under side.
[Fig. 137]
Fig. 137--Model for demonstrating the brain (dissectible).
A prepared nervous system of a frog (such as may be obtained from supply
houses) should also be examined. Observe the appearance and general
distribution of the nerves and their connection with the brain and spinal
cord. If such a preparation is not at hand, some small animal may be
dissected to show the main divisions of the nervous system, as follows:
*Dissection of the Nervous System* (by the teacher).
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