Hygienic Physiology : with Special Reference to the Use of Alcoholic Drinks and Narcotics

by Joel Dorman Steele

THE SYMPATHETIC SYSTEM contains the nerves of organic life. It consists of a double chain of ganglia on either side of the backbone, extending into the chest and abdomen. From, these, delicate nerves, generally soft and of a grayish color, run to the organs on which life depends—the heart, lungs, stomach, etc.—to the blood vessels, and to the spinal and cranial nerves over the body. Thus the entire system is bound together with cords of sympathy, so that, "if one member suffers, all the members suffer with it."

Here lies the secret of the control exercised by the brain over all the vital operations. Every organ responds to its changing moods, especially those of respiration, circulation, digestion, and secretion,—processes intimately linked with this system, and controlled by it. (See p. 330.)

CROSSING OF CORDS.—Each half of the body is presided over, not by its own half of the brain, but that of the opposite side. The motory nerves, as they descend from the brain, in the medulla oblongata, cross each other to the opposite side of the spinal cord. So the motor nerves of the right side of the body are connected with the left side of the brain, and vice versa. Thus a derangement in one half of the brain may paralyze the opposite half of the body. The nerves going to the face do not thus cross, and therefore the face may be motionless on one side, and the limbs on the other. Each of the sensory fibers of the spinal nerves crosses over to the opposite side of the spinal cord, and so ascends to the brain; an injury to the spinal cord may, therefore, cause a loss of motion in one leg and of feeling in the other.

REFLEX ACTION.—Since the gray matter generates the nervous force, a ganglion is capable of receiving an impression, and of sending back or reflecting it so as to excite the muscles to action. This is done without the consciousness of the mind. [Footnote: Instances of an unconscious working of the mind are abundant. An illustration, often quoted, is given, as follows, by Dr. Abercrombie, in his Intellectual Powers:

"A lawyer had been excessively perplexed about a very complicated question. An opinion was required from him, but the question was one of such difficulty that he felt very uncertain how he should render it. The decision had to be given at a certain time, and he awoke in the morning of that day with a feeling of great distress. He said to his wife, 'I had a dream, and the whole thing was clearly arranged before my mind, and I would give anything to recover the train of thought.' His wife said to him, 'Go and look on your table.' She had seen him get up in the night and go to his table and sit down and write. He did so, and found there the opinion which he had been most earnestly endeavoring to recover, lying in his own handwriting. There was no doubt about it whatever."

In this case the action of the brain was clearly automatic, i. e., reflex. The lawyer had worried his brain by his anxiety, and thus prevented his mind from doing its best. But it had received an impulse in a certain direction, and when left to itself, worked out the result. (See Appendix for other illustrations.)] Thus we wink involuntarily at a flash of light or a threatened blow. [Footnote: A very eminent chemist a few years ago was making an experiment upon some extremely explosive compound which he had discovered. He had a small quantity of this compound in a bottle, and was holding it up to the light, looking at it intently; and whether it was a shake of the bottle or the warmth of his hand, I do not know, but it exploded in his hand, and the bottle was shivered into a million of minute fragments, which were driven in every direction. His first impression was that they had penetrated his eyes, but to his intense relief he found presently that they had only struck the outside of his eyelids. You may conceive how infinitesimally short the interval was between the explosion of the bottle and the particles reaching his eyes; and yet in that interval the impression had been made upon his sight, the mandate of the reflex action, so to speak, had gone forth, the muscles of his eyelids had been called into action, and he had closed his eyelids before the particles had reached them, and in this manner his eyes were saved. You see what a wonderful proof this is of the way in which the automatic action of our nervous apparatus enters into the sustenance of our lives, and the protection of our most important organs from injury.— DR. CARPENTER.] We start at a sudden sound. We jump back from a precipice before the mind has time to reason upon the danger. The spinal cord conducts certain impressions to the brain, but responds to others without troubling that organ. [Footnote: There is a story told of a man, who, having injured his spinal cord, had lost feeling and motion in his lower extremities. Dr. John Hunter experimented upon him. Tickling his feet, he asked him if he felt it; the man, pointing to his limbs, which were kicking vigorously about, answered, "No, but you see my legs do." Illustrations of this independent action of the spinal cord are common in animals. A headless wasp will ply its sting energetically. A fowl, after its head is cut off, will flap its wings and jump about as if in pain, although, of course, all sensation has ceased. "A water beetle, having had its head removed, remained motionless as long as it rested on a dry surface, but when cast into water, it executed the usual swimming motions with great energy and rapidity, striking all its comrades to one side by its violence, and persisting in these for more than half an hour.">[ The medulla oblongata carries on the process of respiration. The great sympathetic system binds together all the organs of the body.

USES OF REFLEX ACTION.—We breathe eighteen times every minute; we stand erect without a consciousness of effort; [Footnote: In this way we account for the perilous feats performed by the somnambulist. He is not conscious, as his operations are not directed by the cerebrum, but by the other nervous centers. Were he to attempt their repetition when awake, the emotion of fear might render it impossible.] we walk, eat, digest, and at the same time carry on a train of thought. Our brain is thus emancipated from the petty detail of life. If we were obliged to attend to every breath, every pulsation of the heart, every wink of the eye, our time would be wasted in keeping alive. Mere standing would require our entire attention. Besides, an act which at first demands all our thought soon requires less, and at last becomes mechanical, [Footnote: "As every one knows," says Huxley, "it takes a soldier a long time to learn his drill— for instance, to put himself into the attitude of 'attention' at the instant the word of command is heard. But, after a time, the sound of the word gives rise to the act, whether the soldier be thinking of it or not. There is a story, which is credible enough, though it may not be true, of a practical joker, who, seeing a discharged veteran carrying home his dinner, suddenly called out 'Attention!' whereupon the man instantly brought his hands down and lost his mutton and potatoes in the gutter. The drill had been thorough, and its effects had become embodied in the man's nervous structure.">[ as we say, i. e., reflex. Thus we play a familiar tune upon an instrument and carry on a conversation at the same time. All the possibilities of an education and the power of forming habits are based upon this principle. No act we perform ends with itself. It leaves behind it in the nervous centers a tendency to do the same thing again. Our physical being thus conspires to fix upon us the habits of a good or an evil life. Our very thoughts are written in our muscles, so that the expression of our face and even our features grow into harmony with the life we live.

BRAIN EXERCISE.—The nervous system demands its life and activity. The mind grows by what it feeds on. One who reads mainly light literature, who lolls on the sofa or worries through the platitudes of an idle or fashionable life, decays mentally; his system loses tone, and physical weakness follows mental poverty. On the other hand, an excessive use of the mind withdraws force from the body, whose weakness, reacting on the brain, produces gradual decay and serious diseases. (See p. 331.)

The brain grows by the growth of the body. The body grows through good food, fresh air, and work and rest in suitable proportion. For the full development and perfect use of a strong mind, a strong body is essential. Hence, in seeking to expand and store the intellect, we should be equally thoughtful of the growth and health of the body.

SLEEP [Footnote: Sleep procured by medicine is rarely as beneficial as that secured naturally. The disturbance to the nervous system is often sufficient to counterbalance all the good results. The habit of seeking sleep in this way, without the advice of a physician, is to be most earnestly deprecated. The dose must be constantly increased to produce the effect, and thus great injury may be caused. Often, too, where laudanum or morphine is used, the person unconsciously comes into a terrible and fatal bondage. (See p. 342.) Especially should infants never be dosed with cordials, as is a common family practice. The damage done to helpless childhood by the ignorant and reckless use of soothing syrups is frightful to contemplate. All the ordinary sleeping draughts have life-destroying properties, as is proved by the fatal effects of an overdose. At the best, they paralyze the nerve centers, disorder the digestion, and poison the blood. Their promiscuous use is therefore full of danger.] is as essential as food. During the day, the process of tearing down goes on; during the night, the work of building up should make good the loss. In youth more sleep is needed than in old age, when nature makes few permanent repairs, and is content with temporary expedients. The number of hours required for sleep must be decided by each person. Napoleon took only five hours, but most people need from six to eight hours,—brain workers even more. In general, one should sleep until he naturally wakes. If one's rest be broken, it should be made up as soon as possible. (See p. 334.)