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.
[pg 303]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 coördinate 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.