203, 204. What is reflex action? Give illustrations. Give instances of the unconscious action of the brain. [Footnote: The cerebellum has its unconscious action in the processes of respiration and in the involuntary movements which are made in response to the senses, as in winking, starting back at a sound, etc. The cerebrum acts automatically in oases familiar to all. A large part of our mental activity consists of this unconscious brain work. There are many cases in which the mind has obviously reasoned more clearly and more successfully in this automatic condition, when left entirely to itself, than when we have been cudgeling our brains, so to speak, to get the solution. Oliver Wendell Holmes has aptly expressed this fact. "We wish," he says, "to remember something in the course of conversation. No effort of the will can reach it; but we say, 'Wait a minute, and it will come to me,' and we go on talking. Some minutes later, the idea we are in search of comes all at once into the mind, delivered like a prepaid parcel, or like a foundling in a basket, laid at the door of consciousness. How it came there, we know not. The mind must have been at work, groping and feeling for it in the dark; it can not have come of itself. Yet, all the while, our consciousness, _so far as we are conscious of our consciousness_, was busy with other thoughts." Some interesting personal experiences upon this point are given in an article entitled "The Antechamber of Consciousness," by Francis Speir, Jr., in the _Popular Science Monthly_ for March, 1888.] Can there be feeling or motion in the lower limbs when the spinal cord is destroyed? What does the story told by Dr. John Hunter show? Give illustrations of the independent action of the spinal cord in animals. What are the uses of reflex action? 205. State its value in the formation of habits. How does the brain grow? What laws govern it? What must be the effect of constant light reading? Of overstudy or mental labor? 206. State the relation of sleep to repair and waste. How many hours does each person need? What kind of work requires most sleep? 206-208. What is the influence of sunlight on the body? Illustrate. Name some of the wonders of the brain. 208-213. What four stages are there in the effect of alcohol on the nervous system? Describe each. Does alcohol confer any permanent strength? What is the physiological effect of alcohol on the brain? On the mental and moral powers? What is the Delirium Tremens? Should a man be punished for a crime he commits while drunk? 214-218. What are the principal constituents of tobacco? What are its physiological effects? Who are most likely to escape injury? Is tobacco a food? What is its influence upon youth? Why are cigarettes specially injurious? What effect does tobacco have on the sensibilities? Name illustrations of the injurious effect of tobacco on young men.