its
branches to different muscles and to the skin.

6. Unjoint the neck and remove the head. Examine the spinal cord where
exposed. Cut away the bone sufficiently to show the connection between the
cord and one of the spinal nerves. On the dorsal root of one of the nerves
find a small ganglion. What is it called?

7. Fasten the head to a small board and remove the scalp. Saw through the
skull bones in several directions. Pry off the small pieces of bones,
exposing the upper surface of the brain. Study its membranes,
convolutions, and divisions.

8. With a pair of bone forceps, or nippers, break away the skull until the
entire brain can be removed from the cavity. Examine the different
divisions, noting the relative position and size of the parts.

9. With a sharp knife cut sections through the different parts, showing
the positions of the "gray matter" and of the "white matter."

NOTE.--If the entire class is to examine one specimen, it is generally
better to have the dissecting done beforehand and the parts separated and
tacked to small boards. This will permit of individual examination.
Sketches of the sciatic nerve, brachial plexus, and of sections through
the brain and spinal cord should be made.

*Location of Nerves in the Body.*--Several of the nerves of the body lie
sufficiently near the surface to be located by pressure and are easily
recognized as sensitive cords. Slight pressure from the fingers reveals
the presence of nerves in the grooves of the elbow (the crazy bone),
between the muscles on the inner side of the arm near the shoulder, and in
the hollow part of the leg back of the knee. These are all large nerves.
Small nerves may be located in the same manner in the face and neck.

CHAPTER XVIII - PHYSIOLOGY OF THE NERVOUS SYSTEM

In the preceding chapter was pointed out the method by which the different
parts of the body are brought into communication by the neurons or nerve
cells. We are now to study the means whereby the neurons are made to
control and cooerdinate the different parts of the body and bring about the
necessary adjustment of the body to its surroundings. This work of the
neurons naturally has some relation to their properties.

*Properties of Neurons.*--The work of the neurons seems to depend mainly
upon two properties--the property of irritability and the property of
conductivity. _Irritability_ was explained, in the study of the muscles
(page 243), as the ability to resp