What is necessary if you would have a strong, healthy brain?—"My brain must be used; my brain must be rested; my brain must be supplied with pure blood."
How must you use your brain?—"In thinking and studying."
How may the brain be rested?—"By sleep."
In what other way may the brain be rested?—"By thinking of something different from that which made it tired."
What two brain-poisons have you learned about?—"Alcohol and tobacco."[[4]]
With what may you show the harm done by alcohol to the gray part of the brain?—"With alcohol and the white of an egg."
How could you show it with these?—"I would pour the alcohol upon the white of the egg."
What would then happen?—"The white of the egg would harden as if it had been boiled."
What is in the white of an egg?—"Water and albumen."