13.  What happens if you drink alcoholic liquors, or snuff, smoke, or chew tobacco?

14.  What is necessary if you would have a healthy brain?

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THE BRAIN AND ITS WORK.

The brain is egg-shaped, and of two parts, the large brain (cerebrum), and the little brain (cerebellum).  These are composed of a white and gray substance, which in the large brain is so folded and wrinkled that it looks like the meat of an English walnut; in the little brain it is so arranged that it resembles a tree, and is called arbor vitae, tree of life.  The mind does its thinking through the large brain, and controls its muscles through the little brain.

A drunken man can not walk straight because alcohol has hurt the little brain; he can not think straight because it has poisoned the large brain.

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[Illustration:  THE BRAIN AND THE SPINAL CORD.]

C, the large brain (cerebrum).  B, the small brain (cerebellum).  S, a portion of the spinal cord.

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QUESTIONS ON THE NERVOUS SYSTEM.

Where is your brain?—­“In my skull.”

What color is the brain?—­“Gray and white.”

What does the brain resemble?—­“Marrow.”

How is the brain protected?—­“By three coats or membranes.”

What may you name these membranes?—­“The outer membrane, the middle membrane, and the inner membrane.”

Describe the outer membrane.  See Formula.

Describe the middle membrane.  See Formula.

What are the nerves?—­“White ashen-gray pulpy cords, which are found in the brain.”

Where do they go from the brain?—­“To every part of the body.”

How many kinds of nerves have you?—­“Two.”

What names are given to the two kinds of nerves?—­“Nerves of motion and nerves of feeling.”

Which is the largest nerve in the body?—­“The spinal cord.”

Where is the spinal cord?—­“It extends from the brain throughout the whole length of the backbone.”

How may you describe the spinal cord?—­“It is a bundle of nerves, etc.”  See
Formula.

Where are the spinal nerves?—­“They pass from the spinal cord to different parts of the trunk and limbs.”

How many pairs of nerves pass from the base of the brain?—­“Twelve.”

Where do the first pair go?—­“To the nose.”

What are they called?—­“The nerves of smell.”

Where do the second pair go?—­“To the eyes.”

What are the second pair called?—­“The nerves of sight.”

Which move the muscles of the eyes?—­“The third, fourth, and sixth pairs.”

Where do the fifth pair go?—­“To the forehead, eyes, nose, ears, tongue, teeth, and different parts of the face.”

The seventh pair?—­“To the different parts of the face.”