Being a very vital part of the system, and from the delicacy of its structure liable to injuries, it is set in the back-bone for protection; and so great is its security that it is only by force of an unusual kind that it can be injured.
"A sound heart is the life of the flesh: but envy is the rottenness of the bones."—Proverbs xiv.
954. How can branches proceed from it, if it is so securely encased in bone?
Because in the bones, on each side of the spinal cord, there are smaller grooves for the transmission of the nervous branches.
955. Of what does the nervous system consist?
Of the brain, the spinal cord, and the branches which are called nerves.