Imágenes de páginas
PDF
EPUB

machine still writing its record the undulations were lower and slower, and at times there were long stretches between them, as if all the ripples were being smoothed to quietness. When this point was reached Bertino was always asleep, no thinking was going on. But with the slightest noise -the moving of a chair, the steps of a passer-by, the striking of the clock in the hospital —there was an instant change. In fact, any sound whatever left its record. At such times Bertino was not always wakened, but his brain proved that it took note of the disturbance, for instantly the line of the writing was disturbed. It traveled higher as well as lower.

On a special occasion Dr. Mosso let Bertino sleep soundly for an hour and a half. He then stepped towards his pillow on tiptoe, and at just the point where the arrow appears in the tracing he said very gently, "Bertino." The man neither stirred nor made any answer. He slept

[ocr errors][merged small]

on; but notice the record. See the increased height of the marks as Dr. Mosso stepped across to Bertino, then see the sudden rise after that. The man did not waken, but his brain had become more active.

At other times, for the sake of testing the brain when it was awake, Dr. Mosso spoke sharply to Bertino. And always when he did it the throbbing increased just there, so that the record stretched upward six and seven times higher than before. Indeed, the blood vessels were now so enlarged with blood that the brain itself was larger. Scientists learned several lessons from these and other experiments.

1. According as the brain is more or less active, so also is more or less blood sent up to it.

2. During sleep the less blood there is in the brain the more soundly do we sleep.

3. The brain responds to outside disturbance even when the owner of it does not waken.

4. When an outside disturbance causes the brain to be active so that more blood goes to it the sleeper does not rest so completely as he did when his brain. received less blood.

This last point controls the action of mothers who are careful of their sleeping children, of doctors who wish to save their patients, and even of cities that are anxious for the welfare of their citizens. In each case the effort is to secure as much quiet as possible for those who sleep.

[graphic][merged small]

When he thinks hard the board will sink at the head and rise at the feet. When he

sleeps it will tip the other way - head up, feet down

Even now men and women in different parts of the country are fighting for freedom from unnecessary noises at night. Doctors claim that these noises are the cause of certain brain disorders, and that even healthy people suffer if they sleep in noisy places. No doubt the time will come when railroad trains and steamboats will pass by more quietly at night.

Dr. Mosso not only counted the pulse of Bertino's brain and compelled it to make its own record but he also did something that seems like weighing thought. He invented a machine which shifts its balance according as the person who lies upon it is resting his brain or using it. If a child on this balance begins to think, the machine dips down at the head, showing that suddenly that part is heavier. We know the reason. Thinking is brain exercise, exercise draws blood to the brain, and blood is heavy enough to be weighed.

But let the same child go to sleep on the same machine and the brain will grow lighter and lighter as thinking ceases, until the head is up again and the feet down. In this way, with thought and sleep alternating, the body might keep up a gentle seesaw.

This machine is so very sensitive that even while the child is asleep, if a door is opened or a chair moved, at once the head sinks a trifle and the feet rise, for the balance of the body has changed. If a student resting on it, being wide awake, begins to think out a hard mathematical

problem or tries to study Greek, the machine tells the story of the blood that is pouring into the brain.

All this helps explain points that we ourselves have noticed. Why do I grow pale when I am frightened? Simply because the blood has gone elsewhere, robbing every tip end of the blood vessels of my face. No wonder I am pale! For the same reason my hands and feet are cold when I am frightened. The blood has rushed to the centers. Hands and feet are left without that which keeps them warm. This also explains why soaking the feet in hot water relieves certain kinds of headache. It draws blood away from the crowded blood vessels of the brain.

Because this constantly moving blood supplies all the nourishment the brain will ever get, because it is rich or poor as nerve food in proportion as we have treated it with wisdom or with folly, our responsibility for the vigor of our brain becomes very great. Those of us who treat it best are apt to be the ones who bear in mind the following facts and act upon them:

I. Blood is the food of the brain.

2. The quality of the blood is improved by keeping it supplied with all the oxygen it can use. (Good ventilation and wholesome exercise are in point here.)

3. The food we eat and the way we eat it (see The Body) improves or weakens the value of the blood. The laws of eating too much and eating when we are very tired apply just here.

« AnteriorContinuar »