connect places remote from each other,
and provide for nervous movements through the body. The nervous system,
may in some respects be compared to a complicated system of telephony, in
which the chains of neurons correspond to the wires, and the brain and
spinal cord to the central station.

Exercises.--1. Give the meaning of the term "cooerdination." Supply
illustrations.

2. What two general conditions are supplied in the body by the nervous
system?

3. Compare the skeleton outline of the nervous system with the bony
skeleton.

4. Sketch outlines of mon-axonic and di-axonic neurons.

5. Give two differences between the neurons and the other cells of the
body.

6. Describe the two general methods of connecting neurons in the body.
What purpose is accomplished by each method?

7. Name and locate the principal divisions of the nervous system.

8. Draw an outline of the brain (side view), locating each of its
principal divisions.

9. If a pencil were placed over the ear, what portions of the brain would
be above it and what below?

10. Describe briefly the cerebrum, the cerebellum, the midbrain, the pons,
and the bulb.

11. Locate and describe the cortex. State purpose of the convolutions.

12. State the general differences between the cranial and the spinal
nerves.

13. Locate and give the number of the dorsal-root ganglia. Locate and give
the approximate number of the sympathetic ganglia.

14. Show how the two portions of the spinal nerves are formed--the one from
the mon-axonic and the other from the di-axonic neurons.

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