Melvin Berger - Advances of Modern Science

This special edit ion is for readers for whom English is;a second language. I t t a n ^ b e read by anyone who has learned 2,000 words of English.

ADVANCES OF MODERN

SCIENCE (Original titleJRIUMPHS OF MODERN SCIENCE)

MELVIN BERGER

,150 L-31

THE LADDER SERIES

The Ladder Series books are specially prepared editions of well-known American books. They have been made easier to read for the enjoyment of readers for whom English is a second language.

The Series is built,on a "ladder" of five steps from 1,000 to 5,000 different English words. Al-though the books have been shortened, they keep the ideas and facts found in the originals.

This book uses 2,000 English words. Some words in the book are above this step and will be found written in boldface letters. They are explained in the Glossary at the back.

The publisher hopes the reader will enjoy this Series, while going up the ladder to more difficult reading.

H P

M O D E R N S C I E

(original title: TRIUMPHS OF MODERN SCIENCE)

by MELVIN BERGER

A Ladder Edition at the 2,000-word level ADAPTED BY CLAIRE COOPEB CUNNIFF

PYRAMID BOOKS NEW YORK

To the memory of Ben Shulman, in appreciation of his deep interest in thlp writing of this book.

ACKNOWLEDGMENTS I wish to express my sincere thanks to the many scientists and science teachers who, through their suggestions and readings of various parts of the manuscript, contributed to this book. Their selfless help was of considerable value to me. I must, however, accept full responsibility for the book's contents. All the final choices and decisions wore mine. Among those I would like to single out for particular thanks are Leonard Berkowitz (psychologist). Dr. Edmund Braun (psychiatrist). Dr. Harold Clear-man (Hofstra University), Philip Ferris (Waidemar Medical Research Labora-tory), Dr. Harold Galef (psychiatrist). Dr. George Pappas (College of Physi-cians and Surgeons), John Patterson (Hoyden Planetarium), Edward Polowayk (Brentwood Junior High School), Denis Puleston (Brookhaven National Labora-tory), Valerie Roberts (Hayden Planetarium), Harry Schachter (City College of New York), Dr. Arthur Shapiro (New York Downstate Medical Center), Dr. Peter Tolins (Cornell University-New York Hospital), and Harold Weinstock (Plainview Junior High School).

ADVANCES OF MODERN SCIENCE {Original title: Triumphs of Modem Science)

Ladder Edition Published March, 1967

Copyright 1964 by Melvin Berger

Library of Congress catalogue card number; 64-16481

This abridged edition is published by arrangement with the McGraw-Hill Book Company, the original publishers.

Printed in the United States of America

Contents

To the Reader '

1. A New Way To Fight Disease 9

2. Chemicals That Cure 18

3. Vitamins 24

4. Virus 3 0

5. DNA, Master Planner of Life . . . . ' 37

6. Discovery of the Unconscious 47

7. The Theory of Relativity . . . . . . . . 59

8. Atoms 72

9. X Rays and Radioactivity 8 3

10. Atomic Energy . '

11. The New Astronomy 109

Glossary 119

This LADDER EDITION has been especially prepared for the beginning reader. It is printed from brand-new plates made from newly set, clear, easy-to-read type.

To the Reader

Each day brings us news of advances in some area of science. These advances are very important to each of us. It takes years of study to learn about a single area of science. How can we get some un-derstanding of the many areas of modern science?

We believe that it is possible to become familiar with the ideas of modern science by looking at several of its major advances. As we read about some of the great men of science making their im-portant discoveries, we learn to understand the thinking that led to their results. In this way we can perhaps learn to think clearly. We also can learn that each discovery depends on many that were made before and leads to new discoveries that will follow.

Three standards were used in deciding which advances to include in this book. They had to be accomplishments of the 20th century, or the years just before this century. They had to be advances in knowledge rather than inventions. And finally, they had to be advances which have made the greatest change in our world.

7

1 A New Way To Fight Disease

Alexander Fleming (1881-1955) always took ad-vantage of accidents and chance happenings.

In 1901 he received the highest score on a test given in England for entrance to a school of medi-cine. He could choose any school that he wanted. He later wrote, I n London there are twelve medical schools. I had no knowledge of any of them, but I had played games against St Mary's, and so to St Mary's I went"

Fleming began to study bacteria for an equally strange reason. He was good with guns, and St Mary's had an excellent gun club which needed new members. After he had completed the four years of medical school, he was invited to work in the laboratory at St Mary's, so that he could re-

9

Advances of Modern Science

main in the gun club. He accepted the position in 1906 and remained at St. Mary's until he died.

Now events began to prepare Fleming for his most important accident, an accident that led to a discovery important for every one of us. In 1908, he wrote a report on the battle against bacteria. He continued to fight this battle all his life. In his report, he listed the methods doctors in 1908 could use to fight the bacteria that cause disease.

First on Fleming's list was vaccination. When a person is given a vaccination, dead or weakened bacteria are put into his body. This causes the body to build its defenses, and protects the person from the disease.

Then there are antitoxins. They are prepared from the blood of animals that have had the poisons produced by certain bacteria put into their bodies. The animal creates a substance in its blood which fights the poison. When this substance is put into a person, it helps him fight the poisons produced by certain bacteria in his body. There are other methods too, such as building the person's strength by rest and good food. And there are medicines that kill certain bacteria.

During the following years, Fleming looked for new ways to fight bacteria. In 1922, he found a sub-stance in tears that was able to kill bacteria. Un-fortunately, the bacteria it killed were not disease-causing bacteria.

In 1928, Fleming was studying a certain kind of bacteria called staphylococci. He was growing these bacteria in dishes that contained a soft sub-

10

A New Way To Fight Disease

stance. Most of the time the dishes were covered, except for short periods of time when he took the covers off to examine the growing bacteria.

The summer of 1928 was hot in London, and windows were kept wide open to catch any little wind. In Fleming's laboratory at St^Mary's the win-dows were open too, and a little piece of dust flew in. This accident led to one of the most important advances of modern science.

A few days later, Fleming found that a blue-green mold was growing in one of his dishes. Flem-ing knew that little pieces of mold were carried by the air. He guessed, therefore, that some mold had come in through the open window, and had settled in the dish when the cover was off.

Many people would have thrown the dish away and started all over again. But Fleming decided to watch what would happen. Imagine his surprise when he found that the area around the mold was clear, and not yellow like the bacteria. Something in the mold seemed to be destroying the bacteria!

Now Fleming used all his skill to leam more about the mold. First he bad to get some pure mold so that he could study it more carefully. He re-moved some of the mold and placed it in a sub-stance where he knew it would grow. It grew very fast. It began as a white substance, then turned dark green. It grew by sending out brandies in the shapes.of pencils, which told Fleming that it was a member of the Penicillium family of molds. (The name actually comes from the' same word as pencil.)

11


The next step was to grow more of the mold so it could be tested on different bacteria. Fleming found that the juice from the mold was a powerful killer of several disease-causing bacteria. He made the mold juice weaker and weaker. Still it was able to kill bacteria.

Fleming wanted to know if all molds produced this bacteria-destroying material. He tried five completely different molds and eight different types of Penicillium mold. Of these, only one type of Penicillium worked against bacteria, and this was the same type as the first mold. Knowing that the mold juice had a great power to kill some kinds of bacteria, Fleming then wanted to know if it was too powerful. Would it be harmful to people? He added some mold juice to a small amount of hu-man blood. Minutes, then hours passed. The blood was not affected by die mold juice.

Fleming then decided to try the juice on a living animal. He put some bacteria into some laboratory rabbits. Then he gave the animals his mold juice. Success again. These bacteria were killed, and the animals had no bad effects.

Now Fleming was ready for perhaps the most important test of allto use the mold juice on a per-son. This was very easy to arrange. Stuart Crad-dock, his laboratory helper, was willing to let Fleming test the mold juice on him. The test was a success. Craddock was not harmed by the mold juice.

Soon after, Fleming decided to name the mold juice. Since it came from the juice of the Penicil-12


Bum mold, he called it penicillin. In June, 1929, Fleming published the first report on penicillin. Instead of the excitement that he expected, how-ever, it received little attention.

There were a few reasons for this lack of in-terest Probably the main reason was that no one was able to obtain pure penicillin. In the mold juice it was mixed with other substances that might prove harmful. Before it could be safely used, the penicillin had to be cleaned so that it contained no other substance. In addition, it was a long and diffi-cult job to grow the mold from which the peni-cillin Was made. Although Fleming kept his faith, penicillin was all but forgotten in the ten years after its discovery.

In 1938, two men at Oxford University, Harold Florey (bom 1898) and Ernst Chain (bom 1906), read Fleming's report. Chain decided to see if he could make pure penicillin. By using new methods, he was able to get some penicillin that was very pure. His penicillin was about 1,000,000 times more active than the mold juice that Flem-ing had used in his early experiments.

Florey and Chain gave 50 animals large amounts of a disease-causing bacteria. Twenty-five of them were given penicillin. Twenty-five were given nothing. In the morning all the untreated ani-mals were dead, and all the penicillin-treated ones were alive. In other experiments, more animals were given other bacteria and then treated with peni-cillin. Every time the penicillin had the same effect

Florey and Chain were ready to test the medi-


cine on humans. The problem was to get enough penicillin and to make the penicillin pure. In Feb-ruary 1941, after two years of building a supply, they had one spoonful of the pure yellow peni-cillin. They believed that this would be enough to treat a person. A young man was dying from bac-teria that had entered hi/blood. There was nothing the doctors could do for him, and it was expected that he would live only a few more days.

Penicillin was given to the man every three hours. The next day his condition improved. In two days the hospital doctor said that one more week of treatment would complete the cure. But the small supply of penicillin was gone! The man lived a few more days and then died.

Although Florey and Chain were not able to save the man's life, they realized that as a test of penicillin, the experiment was a success. If there had been enough penicillin, they would have been able to save the man's life.

Another supply of penicillin was obtained. Treatment on another man was begun. But again the supply of penicillin was gone before the man was completely cured. At last, in May 1941, pen-icillin saved a human life. A 48-year old man was seriously ill. After seven days of treatment with penicillin, he was completely cured.

These experiments proved that penicillin killed disease-causing bacteria. One problem remained supply. Florey decided to ask Americans for help. Within a few months, the United States govern-ment and the big United States manufacturers of

14


medicine were all working on the problem. They used every method they knew. Yet, at the end of a year of work they had to report that they had made no real progress.

By now the United States was in World War Two. There was a demand for penicillin to relieve the suffering of the wounded. The supply was far less than the demand. All the penicillin was being made from the same kind of mold that Fleming had used. Many different molds had been tried, but none had worked as well. One day another kind of Penicillium mold was found. This mold was grown in the laboratory, and was found to pro-duce much greater amounts of penicillin than the original kind.

Soon afterward, a new substance was found for growing the mold. It produced 20 times as much penicillin as the old substance. Now more peni-cillin could be produced. By 1945, more than 1,000 pounds of penicillin were being produced each month. As more penicillin became available, more uses were found for i t By 1952, 31 million people were being treated with penicillin.

Experiments with penicillin continued, and new kinds were developed. These different kinds of pen-icillin were able to fight more kinds of bacteria. Other experiments were done to answer an-other question. How does penicillin attack bacte-ria? The first part of the answer came when it was found that penicillin works only against growing bacteria. If the bacteria are not growing they are not affected by the penicillin. Next it was found that

1*


penicillin stopped the bacteria from building cell walls. Bacteria are one-celled plants, surrounded by cell walls. Without these walls, new bacteria cannot form. This discovery also explained why penicillin had worked against bacteria without harming human cells. Human cells do not have walls like the bacteria. They just have a thin out-side layer.

Penicillin was important not only for what it could do, but because it represented a completely new approach to fighting disease. Penicillin was the product of a living thing (mold) that could kill other living things (bacteria). The name for such a substance is antibiotic, meaning against life.

There were hopes that with penicillin man would soon win the war against disease. But by 1948, a hospital in Australia reported bacteria which had become stronger than penicillin. How had these new stronger kinds of bacteria developed?

It is now believed that in the process of killing some bacteria, penicillin had produced these new, powerful ones. As the penicillin attacked bacteria, it quietly killed most of them. But a few were strong enough to remain alive. These stronger bacteria were then able to spread and to fill the space emptied by the weaker bacteria. This new kind, coming from bacteria not harmed by penicillin, was also not hurt by penicillin.

There were still other problems with penicillin. Some people became sick after taking it. Also, many diseases could not be treated with penicillin. The search continued for new and better antibiotics.

16


There are antibiotics to attack bacteria not harmed by the older antibiotics; antibiotics that do not make people sick; and combination antibiotics that work against many bacteria. _

When penicillin was first used, it seemed that we had won our fight against disease-causing bac-teria. The bacteria are beginning to fight back. But now that we have met the enemy and have become familiar with his habits, we are getting ready to carry this fight through to victory.

17

Chemicals That Cure

Laboratories in Germany at the beginning of the century were a strange sight Bottles were Med with brightly colored liquids. The coats of the men were covered with yellow, red, and blue. Even their hands and notebooks were many colors. The large chemical factories did many experiments in the hope of finding new uses for their products.

Paul Ehrlich (1854-1915), even as a student in a school of medicine, was interested in chemicals for making colors. His professors would sadly shake their heads when young Ehrlich studied the effects of these chemicals on human cells instead of cutting dead bodies to study the different parts. What kind of doctor would he make, so busy with his color-making chemicals that he had no time to 18

Chemicals That Cure

learn the long lists of diseases and medicines that doctors must know?

With much difficulty, Ehrlich did become a doc-tor. But his first love still was chemicals and their effect on animal and human cells. In one now-fa-mous experiment, Ehrlich put a blue chemical into a living animal. He later cut open that animal and found that only certain cells had become blue. Why had just some been colored? Why not others? Ehr-lich reasoned that there was an attraction of some kind between the chemical and certain cells.

Perhaps, he thought, he could find a chemical that would be attracted to the disease-causing bacteria in the body. Then, perhaps he could replace the chemicals with a medicine to kill the bacteria.

To start, Ehrlich chose one type of trypanosome. Trypanosomes are very tiny disease-causing ani-mals. One type is responsible for African sleeping sickness. Other types of trypanosomes are respon-sible for diseases in horses and cattle.

Ehrlich and his helpers started the long job of testing chemicals, old and new, to find one that would color, and perhaps kiU, the trypanosomes. Finally, in 1904, they found a red chemical that could kill trypanosomes in laboratory animals. However, it did not cure horses who had the try-panosomes. Nevertheless, it was a good start on the road to fighting disease with chemicals.

Ehrlich read of experiments in which trypano-somes were killed by a substance called atoxyl. Atoxyl was a chemical containing a common poison. Although atoxyl killed the trypanosomes, it had bad

19


effects on the animals in the process. Ehrlich de-cided to experiment with atoxyl. He wanted to change the atoxyl so that it could kill the trypano-somes without causing other bad effects.

During the following years, Ehrlich kept chang-ing the atoxyl. Over 600 different kinds were tried. In each case, Ehrlich had to find out first how much of the new chemical was necessary to kill the trypanosomes. Then he had to find out how much could be given to the animal before it be-gan to cause bad effects.

Thousands of animals had to be used in the search. Finally, in 1909, Ehrlich tried the 606th kind of atoxyL At last he found one kind of atoxyl that seemed to work. It was able to kill the trypano-somes in animals without causing sickness.

Ehrlich read a report that the human disease, syphilis, was caused by a tiny animal of the same family as trypanosome. Syphilis is a disease that was attacking many people. At first there were dif-ferent sores on parts of the body. Sometimes even death resulted The big question was: Could 606 cure syphilis?

Ehrlich returned to the laboratory again to test the effects of 606 on syphilis, He found that by using 606 he could make the syphilis sores in ani-mals disappear in three weeks. 606 seemed to work. He felt ready for human tests. He sent sam-ples of 606 out to doctors and hospitals. By April 1910, the first reports were in. 606 could cure syphilis if it was used early enough in the disease.

20

Chemicals That Cure

Ehrlich's dream had become true. Treating dis-ease with chemicals was a reality.

Encouraged by the success of 606, E. G. Farben Industries tried to find other chemicals that can kill bacteria. In their laboratories, chemical after chemical was tested on bacteria in- glass con-tainers. If the chemical killed the bacteria, it was given to a laboratory animal that had been given the disease. But in every case, the chemical killed the test animal, too.

In 1930, after E. G. Farben had been experiment-ing some 20 years with no success, Gerhard Domagk (born 1895) had an idea that seems very simple to us now. Perhaps, Domagk thought, since the chemical they were looking for was to kill bac-teria in living beings, the first test should be on a live animal, instead of in a laboratory bottle.

Domagk started by retesting the chemicals that had been only slightly active against the bacteria. He gave these chemicals to laboratory animals that had first been made ill with streptococci bacteria. (These are deadly bacteria that can cause blood poisoning and other human diseases.) The amount of streptococci was strong enough to kill the ani-mal within five days. If, at the end of five days, the animal was still alive, the chemical was tested further. This experiment went on for a long time as each of the chemicals was tried. There was failure after failure after failure, however, in the search for a chemical that would kill these bac-teria.

At last, a chemical called prontosil red was tried.

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The sick laboratpry animal got better and suffered no other ill effects. Could this be the chemical for which Domagk was looking?

The first human test of the prontosil came much sooner than Domagk wished. His daughter became very xLL The illness spread through her body. Doc-tors tried every method they knew to help her, but nothing helped. Her condition was very poor. Domagk decided to use the prontosil. How Domagk must have suffered as he waited, hour after hour, to see the effect of the medicine. At last, he saw re-sults. His daughter started to improve. Prontosil cured her as no other medicine had been able to do. And, best erf all, it did not have any bad effects. Prontosil had very successfully passed its first hu-man test

For nearly three years, tests continued on pronto-sil. It had to be tested, not on one or two patients, but on hundreds. Finally, in February 1935, the first public announcement was made. Prontosil had an almost perfect record erf cures.

Some scientists wanted to know more about why and how prontosil acted as it did. They made many studies of i t One part, they found, was a rather simple substance called sulfanilamide that had been known since 1908. It was this part that was active against bacteria. The rest of the prontosil seemed to have no part in fighting the germs.

The sulfanilamide is so similar to a substance needed by the bacteria that they sometimes pick up the sulfanilamide by mistake. Since the bacteria cannot use the sulfanilamide, the bacteria do not

22

Chemicals That Cure

grow, and the body is soon able to get rid of them.

Sulfanilamide is safe for humans because of the way our bodies work. Our bodies do not use the substance that is like sulfanilamide. Only the bac-teria are fooled by the similarity.

In time, other chemicals like sulfanilamide were developed. They were, more powerful than sul-fanilamide. They could attack bacteria other than those attacked by sulfanilamide, and did not cause the dangerous effects that some people suffered from using sulfanilamide.

The 20th century has seen two major advances in man's fight against disease. One is fighting bac-teria with chemicals created by man. The other is fighting bacteria with the products of other living things, such as penicillin. Many diseases have dis-appeared and millions of cures have resulted.

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Vitamins

During the 1880"s, Takagi Kanehiro, a member of tie Japanese navy, was in the habit of meeting the boats returning from long voyages at sea. The. scene was always the same. First, there was a rush of men off the ship. Then came a line of men who walked slowly. Still others could not walk and had to be carried. After any long voyage, one out c every three men returned home either sick or dying.

Takagi did not know what caused the men's ill-ness. He knew only that they had beriberi, a dis-ease that was killing millions of people every year in the Far East. At first, the diseased person had difficulty moving and walking. Death soon fol-lowed. 24

Vitamins

To protect his men, Takagi began to search for a way to cure beriberi. He found that if the men were given another grain along with the usual rice, fewer of them got beriberi. Although he had no understanding of why the other grain worked, he ordered every ship to carry a supply of i t

His discovery led others to study the disease. But beriberi remained a killer in the Far East It was only after 50 years and many experiments that a way was found to fight beriberi. Then, not only did men of science find the cause and cure for the disease, but they also began to understand vita-mins.

At the beginning of tins century, the Dutch gov-ernment sent a team of doctors to the Dutch East Indies ..to learn more about beriberi. For two years, the group looked with no success for the cause of beriberi. However, one of the doctors, Christiaan Eijkman (1858-1930), noticed some-thing important.

Eijkman noticed something special about the chickens at one of the prisons'on Java, where he was studying the health of the men. These chickens had a strange walk that reminded Eijkman of the ap-pearance of people sick with beriberi. Could the chickens have some kind of beriberi? Why should the prison, chickens have beriberi while the chick-ens outside the prison seldom got the diseiase?

Eijkman was curious. He found that the chickens were fed prison food. The main food of most people in Asia was rice. Since whole rice grains soon spoiled, rice was "polished." That is, the outer part,

25


as well as an inside covering called the silver-skin^ was removed. Chickens who lived in the country outside the prison ate seeds and insects as well as rice.

Eijkman believed that the polished rice would give the answer to the mystery of beriberi. He set up experiments to test his theory. He selected some healthy chickens and divided them into three groups. Group 1 was fed whole-grain rice, with the outside and silver-skin. Group 2 was fed rice, with only the outside removed. Group 3 was fed pol-ished rice, with both the outside and silver-skin removed. After a few days, all of the Group 1 and Group 2 chickens were still healthy. Many of the chickens in Group 3, however, had beriberi.

Eijkman now believed the polished rice was a cause of beriberi. He fed the sick chickens of Group 3 silver-skins and the outsides from pol-ished rice. Within a few hours, they all were better.

It is easy today to explain exactly what hap-pened. The silver-skin contains vitamin Bi or thia-min. When the outside of the rice is taken off, the vitamin is removed. A lack of vitamin Bi causes beriberi. When Eijkman fed the chickens the out-sides and silver-skins, he was giving them vitamin Bly which cured the beriberi.

But Eijkman, working nearly 70 years ago, did not know this. He believed that there was some-thing in the ripe that caused beriberi. He was so close, and yet so far from an understanding of vita-mins.

Yet his work was very important. For the first

26

Vitamins

time, beriberi could be caused and cured by man. Now others could use this method to find the actual cause and cure of the disease.

A famous experiment was performed by Sir Frederick Gowland Hopkins at Cambridge Uni-versity in 1906. He took one group of young ani-mals and fed them certain foods. At the end of 20 days the animals had not gained any weight He fed another group the same foods, but added just a few drops of whole milk. The weight of these ani-mals nearly doubled in the same time. This meant there was some unknown substance in the milk that was necessary fear growth. Today we know this substance was vitaminA.

In 1911, Casimir Funk, working in London, re-peated Eijkman's experiment He produced beri-beri in chickens by feeding than polished rice, and then cured it by feeding them the outside of the rice. Funk then took from the outride die sub-stance that could, by itself, cure beriberi. Today we know this substance to be several B vitamins, called the vitamin-B complex. Since the substance he found contained several chemicals, Funk was not able to find out very much about i t He decided to call it vitamine. Later, the final e was dropped.

In 1925, B.CJP. Jansen and W. F. Donath, were able to get the first pure vitamin Bi. The work of Jansen and Donath showed others the way to dis-cover many other vitamins. First, certain foods were fed to animals, while they were carefully watched for disease to develop. Then, a food was found that could cure the disease. Finally, the sub-

27


stance in the food that cured the disease was separated. By this approach, well over a dozen differ-ent vitamins were found. In time, too, the chemical form of the vitamins was discovered as well as ways to create man-made vitamins in the laboratory.

Every time, the vitamin proved to be a substance needed to keep the body in good health. It was also discovered that only small amounts of the vita-mins are needed. If, however, these small amounts are missing, diseases develop. If treatment with vitamins is started soon enough, the disease or poor health can usually be cured. '

At first it was believed that there were only two vitaminsvitamin A and vitamin B. Later the list was extended to vitamin K. Vitamins A, the B group, G, D, and K are the important vitamins needed by man.

Vitamin A is important for seeing in the dark. Good sources of vitamin A are the yellow vege-tables. Actually, they do not contain the vitamin itself, but they do contain a substance which the body can change into vitamin A.

A dozen vitamins in the B group are known to-day. We call them by their chemical names, rather than the numbers that were originally used. Thia-min, niacin, and riboflavin are the best known.

Thiamin prevents and cures beriberi. It also makes people feel like eating. It can be found in whole grains and milk. If the body gets less than the tiny amount of niacin that it needs every day, serious skin disease may result. Good sources of niacin are meat, eggs, and whole grains. Ribo-

28

Vitamins

flavin is necessary in very small amounts. It keeps the skin and eyesfaealtfay. Good sources are milk and meat.

Vitamin C is still a mystery. We know that cer-tain fruits are good sources of this vitamin.- We know too that a lack of vitamin C results in a disease that affects the gums and teeth and smaller blood vessels. But it is still not known how it works in the body.

Vitamin D controls the maimer in which bones grow. A lack of vitamin D affects the development of the bones, and may result in a disease called rickets. Good sources of vitamin D are fish oils, butter, and the yellow part of eggs.

Another vitamin, vitamin K, is important in stopping blood from flowing from a cut Vitamin K, which is found in green leafy vegetables, does not have to be in the foods we eat It is usually manufactured by bacteria to the body.

In reading about vitamins it is easy to worry about getting enough of all the different vitamins. Actually, if you eat the right foods, you will get all the vitamins your body needs. Hie amounts we need are so small that an entire day's vitamin re-quirements can be rolled into a very tiny ball. Yet, you must have these tiny bits of vitamin to keep you in good health.

39

Virus

Parents would have you believe that there were no such things as viruses when they were children. "Today," they say, "every time you are sick, it is a virus. When I was young, we never had viruses." To hear them speak, it is easy to get the idea that viruses were invented ten or 20 years ago. Viruses, however, have existed as long as man. They may have been the first life on earth. But it was only 70 years ago that they were first discovered, and only within the last 30 years has, real progress been made in understanding what viruses are and how viruses work.

Today we know that more than 100 human dis-eases are caused by some virus. In fact, it is be-lieved that viruses cause more than one-half of all diseases of modem man. 30

Virus

A Dutch scientist, Martinus Willem Beijerinck (1851-1931), was the first to study viruses. He taught at the laboratory at the Delft Polytechnical School.

Early in his life, he became interested in a dis-ease of the tobacco plant, Beijerinck's interest in this disease led him to the study of viruses which he continued studying all of his life.

For 20 years, he led a search for the cause of the tobacco disease. He tried to learn if bacteria caused the disease. Test after test failed to show the pres-ence of bacteria. Part of his plan was to discover the size of the disease-causing substance. He ground up some diseased leaves, pressed out the juice, and pressed this juice through a filter. The filter would not allow anything as large as bacteria to pass through. He examined the filtered liquid. It looked clear. Yet, when he applied the liquid to healthy tobacco plants, they soon developed the to-bacco disease. What was smaller than bacteria and could cause disease? Could it be a liquid poison? No. No poison could grow as this substance could. This substance was able to spread and grow on leaves, and the new material was also able to at-tack healthy leaves.

After many experiments and much thought, Bei-jerinck reported, in 1898, that it was a "live fluid" that caused the tobacco disease. He called it virus. Since the virus was able to pass through the filter, it was a filterable virus.

Beijerinck learned that a Russian, Dmitri Ivan-owski, claimed that he had done the same experi-

31


ments earlier. Beijerinck accepted the claim that Ivanowski was the first to discover a virus.

Today, however, Beijerinck is considered to have been the first man to study viruses. Although Ivan-owski performed the experiments a few years ear-lier, Beijerinck was the first to recognize how important the discovery was. Until this time, it was believed that the cell was the base of all life. Bei-jerinck suggested that this substance, although alive, had no cells. He knew that anything as large as a cell would have been caught in his filter. A substance, he said, could be alive and have no cell. That is why Beijerinck called the substance a "liv-ing fluid."

But exactly what is a virus? Is it a chemical fluid that has life? Or is it a living thing without a cell? Men of science began to study the mystery.

Wendell Stanley (born 1904) was one of those who worked to find answers to the mystery of the virus. As a young man, he was offered one of the greatest honorsan opportunity to work at the Rockefeller Institute in New York City. Later he moved to the Rockefeller Plant Laboratory in Princeton, New Jersey. There he started his lifelong study of the virus. His first thought was to choose a virus for study.

He chose the tobacco virus because it was easy to get and to grow. It was a strong virus, hard to de-stroy during experiments; and it was a plant virus, so that the scientist did not have to use animals. Thus began three years of very hard work. His ob-32

Virus

ject was to separate the pure virus by chemical methods.

He planted tobacco plants and watched them grow. While they were still young, he gave them tobacco disease. Then the plants were frozen and cut into tiny bits. He pressed out the tobacco juice that he knew contained the virus. Then he per-formed all sorts of chemical operations on the juice. After each one, he had to test. Did he still have the virus? Could the juice still harm the leaves, or had he lost the virus along the way?

After years of observing the tobacco juice as it became more and more pure, Stanley one day noticed a new shine on the liquid. He examined it carefully in the laboratory. What he found was the pure tobacco virus. The pure substance proved to be a hundred times stronger than the juice from the diseased leaves. He had accomplished the task he had set for himselfto get the tobacco virus out of the diseased leaves. After years of cutting and pressing, and dozens of chemical steps, Stanley had obtained less than a spoonful of a fine, white pow-der.

Stanley took the position that the powder was a chemical substance without life. Who had ever heard of such a thing? How could disease be caused by a substance that was not alive?

The pure virus could be kept in a bottle, just like hundreds of other chemicals. Yet, when this partic-ular chemical is placed on a living thing, it comes to life. As long as it is on a living material, it grows.

The difficult question still remainedwhat is a

33


virus? Is it living or chemical? Men of science had always thought life and not-life to be as different as black and white. With the discovery of the virus, they became aware of a gray area that was neither black nor white.

Until the 1930"s, it was accepted that there was also a great difference in size between the largest chemical molecules and the smallest living things. As new and much finer filters were invented, men were able to measure virus. The first virus to be measured was found to be about 100 millimicrons. (A millimicron is about 1/25,000,000th of an inch.)

The largest known chemical molecule measures only 22 millimicrons. The smallest living thing measures almost seven times that size or 150 milli-microns. When viruses were measured, they were found to range in size from 16 millimicrons to 300 millimicrons. Most were found to be larger than the largest chemical molecules and smaller than the smallest living things.

The answer to the puzzlewhat is a virus? must be that it is both living and not-living. In a living cell, it is a live substance. In a bottle, it -is nothing more than a chemical. We now realize that the virus is actually a bridge between life and not-life.

Less than two years after Stanley's work, two English men, Frederick C. Bawden and Norman W. Pirie, found something else in the tobacco virus that Stanley had not seen. They discovered that although most of the virus was protein, a small 34

Virus

part was nucleic acid, similar to the substance found in the nucleus of the cell.

The nucleic acid in the virus was studied closely by Alfred D. Hershey and Martha Chase at the Carnegie Institution Laboratory at Cold Spring Harbor in New York. In 1952 they were working with a type of virus that attacks bacteria rather than plants. They formed an experiment to learn how the virus attacks bacteria. Hershey and Chase were able to follow both the protein and nucleic acid of the virus in an attack on bacteria.

To understand their findings, imagine the virus as a glass pipe with a hollow ball at one end. This is the protein. Inside is the nucleic acid. The open-ing of the glass pipe makes a hole in the wall of the bacteria. Then the nucleic acid flows into the cell. The empty pipe (the protein) stays on the out-side.

For about 30 minutes nothing seems to happen. Then suddenly the bacterium falls apart, and out of it come some 200 to 300 new viruses, each look-ing for other bacteria to attack!

Only the nucleic acid enters the bacteria; the protein remains outside. Yet, the new viruses have both the nucleic acid center and the protein coatl Somehow this chemical, the nucleic acid, is able to direct the bacteria to make both nucleic acid and protein.

How does the nucleic acid in the virus make not only itself but the protein coat of the virus? Thus, our story of virus ends with a question. We have gone from Beijerinck's "live fluid," through Stanley's

35


pure white powder, to Hershey and Chase's study of the action of virus. These scientists and many others have answered many of the questions about virus. But, as so often happens in science, these an-swers have created new questions. Perhaps the most exciting question raised by the study of the virus is one that we shall try to answer in the next chapterwhat is nucleic acid and how does it work?

36

DNA, Master Planner of Life

The discovery of DNA, one of the nucleic acid "brothers," is like a mystery story. The main differ-ence is that our story, instead of telling of tie search for a master killer, tells of the search for the master planner of life.

First, let us meet our hero. DNA was discovered hiding in the center of a cell by a Swiss, Frederick Miescher, in 1869. Miescher was very interested in the cell's center, the part of the cell that was be-lieved to be concerned with growth.

There are three main parts in every human or animal cell. First, it has a thin outside shell called a cell membrane. Inside the cell there is a small, rounded body called a nucleus. Filling the rest of the cell is a material called cytoplasm.

37


Within the nucleus there are threads of material called chromosomes. The chromosomes are impor-tant in the process of making new cells. The chrom-osomes make copies of themselves and then sepa-rate. The cell splits into two cells, each containing chromosomes.

For his experiments, Miescher chose white blood cells. All attempts to separate the nuclei failed. Then Miescher thought of a way to separate the nucleus from the cytoplasm of the white blood cell. He knew that the cytoplasm was protein and that a substance found in the stomach attacked protein. So he mixed some of this substance with his cells. Within a few hours, a tiny gray powder set-tled out from a clear yellow liquid The gray pow-der was the nuclei of the cells. Miescher called the substance within the nucleus, nuclein. Later its name was changed to nucleic acid.

Work continued on cells, but the nucleic acid was almost forgotten for more than 40 years. In 1931, a German, Joachim Hammerling, was work-ing on tiny one-celled plants called Acetabularia. Each Acetabularia has a body and a cap, and each type of Acetabularia has its own cap shape. It was know that if the cap of an Acetabularia was cut off, a cap of the same shape would grow again.

In Hammerling's experiment, he put the nucleus from the stem of one type of Acetabularia (we will call it type 1) into the stem of a different type (type 2) that had had a cap removed. He watched to see which cap would grow on type 2. Would the new nucleus affect the shape of the cap? It didl

38

DNA, Master P l a n r i p r of Life

The type-1 cap shape grew on the type-2 Acetabu-laria. For the first time, it was shown that it was the nucleus, and the nucleus alone, that deter-mined how the plant would grow.

Still, the nucleic acid was almost forgotten. In 1944, Oswald T. Avery and others at the Rocke-feller Institute in New York were studying some experiments done earlier by Fred Griffith. Griffith worked with two different bacteria, one that had a rough coat, and one that had a smooth coat Griffith used a quantity of rough-coated bacteria that had been so weakened that they could not cause disease. Along with these he used a large quantity of dead smooth-coated bacteria. He gave both to an animal. Since the rough were too weak, and the smooth were dead, he expected nothing to happen. But the animal did get sick. And its blood, when examined, was filled with living smooth bacterial

The men at the Rockefeller Institute decided there must be some substance that could change weak rough bacteria and dead smooth bacteria into living smooth bacteria. Avery put the two types through a long series of chemical operations. Fi-nally, the substance was separated. It came from the dead smooth type. It was able to direct the roughs to make the smooth type. You can probably guess the rest "It" was our long forgotten hero-nucleic acid. Somehow the nucleic acid from the dead smooth-coated bacteria was able to direct the processes of the rough-coated bacteria. It was able to direct the roughs to make smooths that were ex-actly the same as the dead smooths.

59


In March 1955, nucleic acid was studied at Wen-dell Stanley's virus laboratory at the University of California. Heinz Fraenkel-Conrat (born 1910) wanted to take apart the tobacco virus, find the part that was responsible for growth, and then put the virus together again.

By this time, it was well known that all viruses contain a nucleic acid center and a protein shell. The question to be answered waswhich part of the virus, the nucleic acid or the protein, was re-sponsible for virus growth? Fraenkel-Conrat was able to remove the protein from the nucleic acid of the tobacco virus. Then, he removed the nucleic acid centers from another amount of tobacco virus. This operation, which sounds so simple, was very difficult.

He rubbed a little of the nucleic acid on the leaves of one tobacco plant, and the hollow protein coat on the leaves of another plant If either had the power of the complete tobacco virus, the leaves would have spots. The next day Fraenkel-Conrat looked at the two plantsand found nothing! He thought for a while that neither the nucleic acid nor the protein, by itself, was able to spread the tobacco disease.

Fraenkel-Conrat had, in effect, taken life apart. Now, this question remained: Could he put the pieces back together and get a virus? He mixed nucleic acid from one virus and protein from an-other. A few minutes later a shine developed on the substance. It was the same shine that Wendell 40


Stanley had seen 20 years earlier when he had dis-covered the tobacco vims. Was it really the tobacco virus? Would it attack the tobacco plaffts?

On Friday he put some on the plants. On Satur-day, there was nothing on the plants. On Sunday, the plants still looked fine. But by Monday morn-ing, the spots of tobacco virus disease had ap-peared. The virus that he had put together in the laboratory was able to give the tobacco disease.

As Fraenkel-Conrat continued working he learned more about the nucleic acid. He found that it was very delicate after being removed from its protein shell. It was able to attack the tobacco plants only if it was applied immediately after sepa-ration. The reason the nucleic acid had not at-tacked the leaves in the first part of the experiment was that he had taken too long to put it on the plants.

What other facts were learned about nucleic acid?

First, it was soon discovered that there are two nucleic acid "brothers"deoxyribo-nucleic acid and ribo-nucleic acids. They were known by their ini-tials DNA and RNA. -

It was learned that a little string of DNA, hid-den in the nucleus of a cell, stores and then sends from one cell to another all the information neces-sary to create a new living thing.

We know that to build even the simplest house requires pages of drawings, details, and measure-ments. How could these little pieces contain plans

41


{or a living being? It did not seem possible, yet everything indicated that it was DNA that did the job.

By 1953, scientists had discovered much more about DNA. They knew that DNA was a huge molecule. They knew that it contained sugar mole-cules and phosphate molecules that were joined to each other. In addition to the sugars and phos-phates, there were four bases that we will call A, G, C, and T. There were thousands of these six dif-ferent pieces, each with its own shape and size, in the DNA molecule.

Two scientists working at Cambridge University in 1953 tried to build a model of a DNA molecule. An Englishman, Francis H. C. Crick (born 1916), and a young American, James Dewey Watson (born 1928), began to build the model with a sup-ply of wire and many pieces of metal. Each piece of metal represented a piece of the DNA molecule, either a sugar, a phosphate, or one of the bases. The wire was used to hold the metal pieces to each other. Crick and Watson tried many times to fit the pieces together. They found that the pieces would not fit where they placed them. Each failure taught them more about the arrangement of molecules within DNA. They realized that only one model would be correct

Finally the pieces began to fit into the right places. The phosphates and sugar molecules formed long curving lines. The four bases were attached to them to form a ladder. The sides of the

42


ladder were made of the sugars and phosphates. The steps of the ladder were the bases, A, G, C, and T.

This was the truthbut it was not the whole truth. The bases were of different sizes. A and G were bigger, longer bases; C Mid T were smaller, shorter bases. How could there be a ladder with steps of different sizes? They discovered that two bases were required for each step. Each step had to contain one long base and one short base. Even so, there are four possible arrangements of the bases that form these steps. And these steps could follow in any order.

s T P - P H O S P H A T E Y S - S U G A R X A . G - T H E LONGER BASES

g J C j T - T H E SHORTER BASES

&

-


same shape (a curving ladder). Only one thing could changethe order of the steps.

Not only must the DNA carry the directions for making new cells, but it must be able to make' copies of itself. The model that Crick and Watson * built gave an idea of how the DNA does this. The process begins with the ladder unwinding at one end. As it unwinds, single bases, A, G, C, and T, are left free. But within the cell fluid, other bases are freely floating. As an example when the broken step with only a T comes near a floating A, the A becomes attached and completes that step. Thus, as the latter unwinds, new bases, with sugar and phosphate attached, complete the ladder. And by the time it is completely unwound, two new lad-, ders have been informed.

This explained how DNA was able to make cop-ies of itself. But how was DNA able to direct the manufacture of proteins? Protein manufacture was done outside the nucleus. Yet, DNA was found only in the nucleus.

Do you recall our mention that there are two nucleic acidsDNA and RNA?

44

DNA, Master Planripr of Life

While the DNA was found only in the nucleus, the RNA appeared in both the nucleus and the cytoplasm, the substance of the cell outside the nucleus. Experiments at the University of Cali-fornia showed that UNA somehow moved from the nucleus out to the cytoplasm.

Then the process became clear. The DNA is the master planner. It contains the directions for the making of living material. Within the nucleus, in a way as yet unknown, the DNA passes its protein manufacturing instructions to the RNA. The RNA then goes out into the cytoplasm to help in the manufacture of die proteins. In some cells, or vi-ruses such as the tobacco virus, it was RNA iot DNA that contained the master plan.

In 1955, Severe Ochoa (born 1905) of New York University was able to make some RNA in the laboratory. This was the first time RNA had been created outside a living cell. One year later, his former pupil, Arthur Kornberg (born 1918), made some DNA while at Washington University in St Louis.

In August 1961, two scientists at the National Institutes of Health in Bethesda, Maryland, were able to make a simple RNA molecule. They put it to work making protein, and found that it pro-duced one part of the protein.

Our mystery story ends here. The nucleic acid brothers, DNA and RNA, are the master planners of life. Within their tiny, curving ladders is con-tained the secret of life.

45


It is the DNA and RNA that determine thatj baby chickens look like chickens, and baby rabbits; like rabbits. It is the DNA and RNA that determine; the color of the eyes and hair, and the weight and height of every baby born.

New evidence is bringing us ever closer to an understanding of the molecules that control life.

46

Discovery of the Unconscious

Science, during the last 500 years, has struck man three cruel blows. In the 16th century, Nicolaus Copernicus proved that the Earth is not the center of the world, but merely a tiny spot in tile vast heavens. In the 19th century, Charles Darwin pro-vided evidence that man had developed from the lower animals. At the beginning of this century, Sigmund Freud struck the cruelest blow of all. He showed that man is largely directed by a part of his mind over which he has no control, that he is not completely the master of what he is, what he thinks, or what he says and does.

As a student at the university of Vienna, Sig-mund Freud (1856-1939) found it hard to decide what to study. Physiology, the study of how the

47


parts of animals and plants work, gave Freud his; greatest pleasure. He soon began to study the; nervous systems of men and animals. As an aid in! this work, he studied medicine and became a doc- ' tor, even though he did not intend to work as a; doctor.

After his marriage in 1886, and as his family be-gan to grow, he realized that he would have to open an office as a doctor to support his wife and his six children. Since his work had been on the nervous system, it is not surprising that Freud treated diseases of the nervous system.

Patients came to his office with nervous condi-tions, such as loss of sight, hearing, or speech, and unreal fears. Some of them worried all the time. Some could not move parts of their bodies. Yet, when Doctor Freud examined them, they seemed to have nothing wrong with their nervous systems. People who have nervous conditions such as these are called neurotics; such a condition is called a neurosis.

Freud found that nothing could be done to help these people. Should he do what the other doctors were doing, and suggest staying in bed in a dark room? Should he suggest exercise? Hot baths? Ice water baths? Since nothing seemed to help, every-thing was suggested. Freud tried them all, but to no effect.

In the 1880's Doctor Josef Breuer, one of Freud's teachers, treated a neurotic patient in a completely new wayand was able to cure the neurosis. The patient was a German girl named Anna O. She

48


could not move her right arm, and she could not remember how to speak German. She could speak only English.

Doctor Breuer put Anna into a kind of sleep that allowed her to listen and talk and follow sugges-tions. While Anna was asleep, Doctor Breuer helped her remember back to the moment when she was first unable to move her arm and when she first forgot how to speak German.

Doctor Breuer learned that one day, while nurs-ing her dying father, Anna had gone to sleep, with her right arm over her chair. When she awakened her arm had no feeling, and from then on she was unable to move it. Some days later, she again fell asleep at her father's bedside. This time she dreamed that an animal was coming out of the wall to attack her father. She tried to call out, but could not. All she could say was an English poem that she had learned as a child. After that, she could speak only English.

Here, then, was the root of the neurosis. The ill-ness and death of Anna's father had been a very difficult experience for her.

Doctor Breuer was able to cure Anna by helping her remember those difficult moments. She was then able to look at them and accept them. As she did this, she found that she was able to move her arm and speak German.

Freud was the first to realize how important Anna's cure was. He used the case as a model for his treatment of neurotic patients. As time passed, Freud made changes and improvements on the ap-

49


proach of Breuer. The result was a new sciencjj called psychoanalysis.

Psychoanalysis is both a new understanding oj how the human mind works and a new way of treating illnesses of the mind. One of the important ideas of psychoanalysis is that we do not know most of our thoughts and feelings and cannot control them. Freud compared the human mind to a bloclej of ice floating in the ocean. Just a small part of thi ice shows above the surface of the water, while most; of the ice is beneath the surface. Freud said that the mind was somewhat like the ice. We know only? a small part of our thoughts and feelings. He called; this part of the mind the conscious. The large part of our thoughts and feelings that we do not know* and cannot control he called the unconscious. j

As you read this page you can prove to yourself ] that the unconscious part of your mind is at work. What are you doing with your hands? Are you bit-: ing your nails? Are you playing with a pen or pencil? Unless you consciously tell yourself to do these things, it is undoubtedly the unconscious part of your mind that is responsible for these actions.

Another idea of psychoanalysis is that all neu-roses come from the unconscious part of the mind.; This idea led to the belief that, if unconscious; thoughts are made conscious, usually die neuroses will disappear. In the case of Anna O., you will re-member that she was cured by having the uncon-scious memories connected with her father's death brought to her consciousness.

If neuroses were to be treated by bringing

50


thoughts out from the unconscious, then a way had to be found to reach into the unconscious. Freud found one approach to reaching the unconscious that became an important part of psychoanalysis an approach he called free association. Patients were asked to let their thoughts wander and say whatever came into their minds. He wanted to hear all memories, dreams, and wishes of his patients. As they spoke, he found they remembered painful memories from the unconsciousmemories that they had long kept hidden.

All of us have memories that we keep hidden in our unconscious. Here is a simple experiment that will give you some idea of how deeply memories are buried. Write a list of ten words, including words such as mother, school, church, and kissing. Ask a friend to tell you the first word that comes into his mind after you read each word.

You will find that some answers take much longer to tell than others. Freud believed that the answers people could not give quickly were in some way connected with painful or unpleasant memories. You will also notice that some answers seem to have no relation to the word you read. These, too, may be somehow connected with unpleasant memories. You will not learn too much about a person by using free association. In the hands of a trained person, however, it becomes a valuable tool.

Have you ever forgotten a telephone number that you knew perfectly well? Have you ever met a friend on the street and called him by the wrong name?

51


Freud explained these errors as struggles be-tween the conscious and unconscious. You had a reason, he would have said, for not remembering the telephone number that you consciously tried to remember. The reason might be that you do not like the person you were going to call or you might have had a recent unpleasant telephone call.

Sometimes it is very easy to see the unconscious thought For example, a young girl asked her mother, "Did you have parties like this when you were alive?" Imagine what the girl thought of her motherl

Just as man has always made errors, he has al-ways dreamed. But Freud, in 1900, was the first to make a careful study of dreams. This gave us still another look into the unconscious mind.

Dreams are a form of mental activity that goes on when a person is asleep. Some dreams may be un-real and seem to make little sense, and others may be so real and clear that we are not sure that we are dreaming. Dreams are a stage on which the un-conscious can act out its needs, fears, desires, and hopes while the conscious mind sleeps.

Mary, a young lady, had this dream: She was driving the old family car, with her father as a pas-senger. She came to a high hill. It was too high for her. She asked her father to drive up the hilL

One way to understand Mary's dream is as a wish to be adult and independent. The hill is a problem she cannot answer for herself. She needs to be a child again and ask her father for help. She wants

52


to be independent at the same time that she wants to depend on her parents.

After studying hundreds of dreams, Freud found that dreams have a language of their own. The lan-guage of dreams deals with symbols, where one thing really means something else. In Mary's dream, the hill was not really a hill, but a big problem. Driving a car was a symbol for being adult and free. These symbols sometimes have meaning for just one person. But Freud found that the same symbols appear again and again in the dreams of different people, at different times and in different places.

House is one such symbol that appears in the dreams of many people. He found that house is often the symbol for the body. Other symbols, he found, were kings and queens for one's parents; water for birth; and a long trip for death. Some-times symbols mean something quite different from what you might expect. Dreams of being in a crowd, for example, often mean that you feel alone; dreams of clothing or a uniform often mean that you feel naked.

These symbols can be a valuable tool in under-standing dreams. To understand the human mind, a doctor does not simply connect dream symbols with their meanings in a book. To the trained doc-tor, dream symbols are another tool of science to help people understand and accept themselves.

The conscious and unconscious parts of our mind form what we are, how we think, how we act, what we want, what we fearour personality. Freud found that one's personality works in three ways.

53


He called these three: id, the ego, and the superego. They are different ways that the mind, or personal-ity, works. They are not different parts of the brain.

Here, in simple terms, is how the personality is put together. The id is the selfish child of the un-conscious. It is not interested in anyone or anything except gathering pleasure when it wants it. Good and bad, right and wrong, mean nothing to the id; whatever it wants, it takes. The id, or "I want," is the source of all energy of the personality.

If the id cannot get an object in reality, then it imagines that it gets it. When the id wants some food, it either eats or imagines it is eatingand is satisfied either way. The id cannot tell the differ-ence between real food and imaginary food.

It is the job of the ego to tell the difference be-tween real and imaginaryand to help the id find it with the least trouble. The ego is the connection between the needs of the id and the real world which can satisfy these needs. The ego has to take care of the entire person, not just satisfy the id. Sometimes the ego gives the id what it wants. Sometimes the ego makes the id wait to get what it wants.

The third part of the personality is the superego. The superego is shaped by the outside world, es-pecially by a child's parents. Through rewards and punishments, the parents pass on to the child their beliefs in what is right and wrong.

The superego also wants to have its own way. To accomplish this, it either rewards or punishes the ego. The rewards are feelings of pride; the

54


punishments are guilty feelings. Sometimes the feelings are so strong that you reward yourself with a new dress or suit, or punish yourself with an ill-ness. This can even happen without your knowing it. Have you ever had a guilty feeling although you do not recall doing anything wrong? This is prob-ably your superego punishing you, not for some-thing you did, but for something you thought of doingl

The id, ego, and superego, are all parts of our personality. The id, "I want," the ego, "I can," and the superego, "I must" or "I must not," sometimes get along very well together, and sometimes they do not.

Within our personality, there are struggles be-tween the id, the ego, and the superego. If the ego gives the id what it wants, the superego may be angry. If the ego says no to the id and obeys the superego, the id is not satisfied. How can the ego defend itself against the damaging effects of strug-gles such as these?

The ego uses many tricks to defend itself against attack by the rest of the personality, as well as by the outside world. These tricks of the ego are called defense mechanisms. Although there are many dif-ferent kinds of defense mechanisms, each of us uses just a few, over and over again,

A favorite defense mechanism is displacement. When you have a fight with a friend and later go home and scream at your mother, that is an ex-ample of displacement. The feelings that were di-rected at one object are displaced, and directed

55


at a safer object. You are afraid to scream at your friend, who may very well scream at you. You scream instead at your mother, since you can be sure of her love.

Perhaps the most important defense mechanism is the one that protects by keeping us from realiz-ing that anything unpleasant happened. The uncon-scious can "forget" bad experiences and memories, so that you are not conscious of them. This defense mechanism is called repression.

Freud gives an example of repression in his own case. Someone was telling him about a sum-mer resort with three hotels. Freud, who had been at this resort many times, insisted that there were only two hotels there. When told the name of the third hotel, Freud realized that it had been re-pressed from his conscious memory because it re-minded him of the name of a doctor whom he disliked.

A very popular defense mechanism, similar to repression, is denial. In repression, the unconscious part of the mind pushes the unacceptable thought or feeling out of your conscious. In denial, you consciously refuse to accept it; you know the truth, but won't admit it Lies that people tell to protect themselves in difficult situations, when they know that they are lying, are examples of denial.

Have you ever started a fight with someone, and explained it by saying, Tie hates me and so it is not my fault"? This rather common situation may be a very clear example of the use of the de-fense mechanism called projection. Projection 56


brings relief to the ego by changing the subject of a feeling. Projection changes "I hate him" to "He hates me." Projection puts thoughts and feelings you find hard to accept onto someone or something else. The purpose of projection is to take difficult situations that are within the personality, and put them outside, where the ego can more easily handle them.

Sometimes the ego is fighting so hard against some sort of attack that it completely turns itself around in a defense mechanism that is called reac-tion formation. Do you know people who are too neat and clean? Others who are too kind? A per-son may like to be dirty but feel very guilty about it. Reaction formation can make him overly neat and clean. Someone else feels angry at the world. He feels guilty and the reaction formation makes him overly kind.

Every one of us uses defense mechanisms in handling problems. A baby begins forming defense mechanisms right after birth. The first time he has to wait even a minute for his milk, he begins to develop ways to understand and ease his pain. Part of Freud's theory of psychoanalysis is that these early experiences are very important in form-ing the personality that is with a person for life.

The infant is almost all id. If a baby could speak, the only words he would use would be, "I want, I want, I want." As he grows, his ego develops and be finds the best ways to get the things that he Wants. The superego develops last, as his parents

57


give him a sense of what is right and what is wrong.

Freud felt that every adult neurosis could be traced back to either a childhood neurosis or some bad experience that left a mark on the personality. He believed that the child's feelings and mental activity were very important.

Sigmund Freud made one of the great advances of modern science. The theories that shocked the world 60 years ago are still held by many in the field of psychoanalysis today. Others have kept some of Freud's ideas, while developing and chang-ing ideas they did not accept. But Freud's ideas still form the foundation from which all later think-ing in psychoanalysis developed.

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The Theory of Relativity

There is a joke about relativity that was very popular some years ago. It told of a man named Smith who wrote a book explaining relativity. Someone wrote about the book: "Smith is greater than Albert Einstein. When Einstein first explained the theory of relativity, only twelve men in the whole world understood him. When Smith explains it, no one understands himl"

We, of course do not want to make the same mis-take as Smith. Today more and more people want to understand relativity. In the New York Public Library alone there are more than 500 books on relativity! Einstein's first explanation of relativity More than a half-century ago shocked the world. Since that time relativity has become accepted.

59


The theory of relativity came indirectly from a question that scientists had thought about for many centurieshow does light get from one place to an-other? By the 19th century, most men agreed that light is a wave movement, like waves in the sea or sound waves. Sea waves are moving water, though, and sound waves need air or some other substance which can be moved. What about light? Sometimes light travels through air or through clear material like glass or water. But what about the light that comes to us from the stars? Most of space is empty, with no air at all. Light, then, must be able to pass through an empty space.

Scientists were very unhappy about the idea that light waves move without moving something. So they invented this "something," and called it ether. Ether was said to be everywhere, filling all the empty spaces and going through all matter. Ether was impossible to see or feel, since it passed right through our bodies.

In 1881 two Americans, Albert Michelson (1852-1931) and Edward Morley (1838-1923), decided to discover whether there really was an ether. Knowing that our earth is moving through space, they expected that this movement would create ail "ether wind."

In their experiments, Michelson and Morley sent rays of light the exact same distance in all direc-tions. They expected that if there was an ethe* wind some rays of light would be pushed faster by the wind, and others held back. They measure^ how long it took the light to travel this same disj 60


tance with, against, and across the ether wind. The result? The light took the exact same length of time, though it traveled in different directions. If there was an ether wind, it did not affect the speed of light.

Several men tried to explain why Michelson and Morley found no ether wind. One idea, stated in 1893 by George FitzGerald (1851-1901), is of in-terest to us. He explained the results of the Michel-son-Morley experiments by saying that the ray of light which they used got shorter as it pushed through the ether wind. He compared it to a ship that gets a little shorter as it goes through the water because of the water pressing on its front end.

FitzGerald was having a difficult time getting anyone to accept his idea. For one thing, it did not seem possible to prove. FitzGerald said that any object that is moving gets shorter in the direction it is moving, and the greater the speed, the shorter it becomes. The only test of this statement would be to hold a measuring tool next to the moving object. But since the measuring tool would also be moving, it too would get shorter!

Two years later, in 1895, Hendrik A. Lorentz (1853-1928), a Dutchman developed a theory of how to measure this change in length. As an exam-ple, a car speeding along at 50 miles per hour is re-duced to its first length times 0.9999999999999. This tells us that the car is .000000000002 inches shorterl This change in length cannot, of course, be noticed. Only at speeds approaching that of light is there noticeable change in length. If you imagine an ob-

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ject moving 93,000 miles a second, which is one-half the speed of light, the object becomes 86 per cent of its first length.

Scientists in all parts of the world studied the Michelson-Morley experiments and the FitzGerald-Lorentz theory. One of the men puzzling about this was Albert Einstein (1879-1955).

Einstein realized how important were the Michelson-Morley and FitzGerald-Lorentz theories. Using their work as a foundation, he gave 20th century science a new understanding of the physi-cal worldthe theory of relativity. It was published in two parts: The "Special Theory of Relativity" in 1905, and the "General Theory of Relativity" in 1916.

The special theory of relativity is based on a few beliefs stated by Einstein. The first, the one that gave the theory its name, is the belief that all mo-tion is relative. For instance, to say that an automo-bile is traveling at 50 miles an hour does not say very much. To make more sense you must say that it is moving 50 miles an hour relative to the earth. But this still does not give the true speed of the car. We know that the earth is moving around the sun. The sun, too, is in movement. Therefore, it is really impossible to determine the true speed of the car, since there is nothing in the universe that is not moving. j

When Einstein applied to the ether his idea thai all motion is relative, he realized that it is not posj sible to find the ether. If it were possible to find the ether, by ether wind or in some other way, thai

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would mean that the ether is fixed and unmoving. Since Einstein believed that all motion is relative, that meant that nothing in the universe could be fixed and unmoving. If there were a fixed ether, this would be the only part of the universe not in motion, and not relative to anything else. Einstein could not accept this idea. Therefore, although Ein-stein does not say there is no ether, he does say that it is impossible to find the ether.

The other statement of the special theory comes from an idea that has been accepted for hundreds of years. The statement applies when a group of objects or people (a system) is in uniform motion. Uniform motion means that the system is either moving at a constant speed (not getting faster or slower or not moving at all. The second statement of the special theory is that there are no experi-ments that you can do in a system in uniform mo-tion or at rest that will tell you whether the system is moving or not.

The next time you are in a car or train moving in a straight line at a steady speed, or in uniform mo-tion, try this experiment. Take a penny in your right hand, and hold it directly over your left hand. Drop the penny. You might expect that in the time it takes the penny to fall, the car has moved you forward, and the penny would not fall on your left hand. Yet you will notice that the penny falls straight into your hand. As long as the car, and you in it, are moving at a uniform speed, the penny falls just as it would if you were standing still. If there Were no windows in the car, it would not be pos-

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sible to perform an experiment to tell you whether you are standing still or moving at a uniform rate. Any experiments that you try in a uniformly moving system will give the same results as if you did them in a laboratory built on the ground.

Einstein took this old law about uniformly mov-ing systems, and added to it. He said that the speed of light in a space that has had all the air removed, as seen by an observer, is always the same. This be-came the foundation of relativity. Einstein wrote that regardless of how the source of light is moving or how the receiver of the light is moving, the speed of light remains exacdy the same to an ob-server186,000 miles a second.

The theory that the speed of light always is the same to an observer seems to go against common sense. For instance, if you are on a train traveling 50 miles an hour, and you walk forward in the train at 5 miles an hour, your speed in relation to the ground is 5 less than 50, or 45 miles an hour.

In his first paper on relativity, Einstein describes a situation where you cannot add or take away speeds. A railroad signal light is shining along the track, traveling at the speed of light, 186,000 miles a second. When a train approaches the light, an ob-server on the train would expect to find the speed of light from the signal to be 186,000 miles a second added to the speed of the train. After the train passes the signal, the speed of its light for the ob-server should be 186,000 miles a second, less the speed of the train. Yet, Einstein said that the speed of light to an observer always stays the same.

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To make sense out of this we have to say that if the speed of light always stays the same then it must be that something else changes. Einstein be-lieved that time is affected by speed. He stated that time slows in a system in motion, and fhe greater the speed, the slower the movement of time. For example, imagine that a man in a plane makes his watch agree with a clock on the ground at twelve o'clock. Then he goes on a trip in space, traveling for the entire time at exactly 93,000 miles a second. When he lands, the clock on land says 1:00 o'clock, but his watch says 12:54.

This story shows that the flow of time is slower for systems in motion. When the plane traveled at 93,000 miles a second, one-half the speed of light, time moved only 9/10 as fast as time does in a sys-tem at rest. That is why an hour passed On earth, but only 54 minutes, which is 9/10 of an hour, on the plane.

The theory also showed that the mass of an ob-ject increases with its speed. (Mass is very much the same as weight.) As an example, if a 150-pound man were to run at a speed of 161,000 miles a sec-ond, his mass, or weight, would be 300 poundsl

Knowing that length, time, and mass are changed by speed, we now come to one of the most interesting and important ideas that came from the special theory. Mass increases with speed, and as an object moves faster and faster, its mass gets greater and greater. For example, if a little ball were traveling at 99.9999999999999 per cent of the speed of light, it would have a mass of thousands of

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pounds. If an object traveled at the speed of light, it would have an endless mass. The same sort of thing happens to length moving at the speed of light. It becomes an imaginary number, and there-fore not possible. Although Einstein introduced us to a strange, new world, even he could not accept endless mass and imaginary length. He therefore concluded that no object can travel faster than the speed of light

The special theory of relativity was not the kind of theory that could be easily tested in the labora-tories.

The first tests of the theory came from studies of atoms. Parts of atoms move at speeds approaching the speed of light. In studying electrons, scientists found that the electrons were being sent out of some substances at different speeds and with dif-ferent masses. Why? They expected all electrons to be alike, and they could not understand the many different weights.

They found that if the electrons all had the same mass when at rest, the very fast, different speeds at which they traveled explained the different masses. Thus, the Special Theory of Relativity seems to work.

As a result of his work on the special theory, Ein-stein arrived at the most famous statement in all science, E = MC2, where E is energy, M is mass, and C is the speed of light. Einstein reasoned in this manner. The mass of an object increases with mo-tion. Motion is a form of energy. If the increased

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mass comes from the increased energy, that means that energy really has massl

The special theory showed that matter and en-ergy are not the completely different things that man had believed for so long. In fact, one can be changed to the other.

In 1916, Einstein published the "General Theory of Relativity," which applies to systems where one system is getting faster or getting slower than the other.

To help us understand this theory, we will go on a series of imaginary elevator rides.

First, we will put the elevator on the top floor of a building, cut the ropes holding it up, and let it freely fall down. Everyone inside the car feels no weight, because the car is dropping from under his feet and he does not weigh on the floor at all. If someone drops a book, it seems to float in the air, because the elevator and its passengers are falling just as fast as the book. If someone jumps up, he slowly floats toward the ceiling. The exact same things would happen in the elevator if it were in outer space, away from the pull of any gravity.

Now, we will put our imaginary elevator out in space where there is no gravity, and have it pulled up by a rope attached to the top. This time every-one feels the right weight, the book falls down when you drop it, and when you jump it is the same as jumping on the ground. The reason all this hap-pens beyond gravity is that the elevator is being Pulled up against your feet, the elevator comes up to meet the book, and the pull makes the jump

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seem perfectly normal. The normal pull of gravity would give the same results if the elevator were still in a building on earth.

Finally, we will put the elevator in the building, and have it going up faster and faster. Since the el-evator is being pulled up against you, you feel much heavier than usual. Because of the feeling of great weight, it is difficult to jump. The same thing would happen in an elevator standing still on a planet with a greater mass than earth, since the greater the mass, the greater the pull of gravity.

What do these stories tell you? They told Ein-stein that it is not possible to tell the difference be-tween gravity and the force of changing motion. This idea is the heart of the general theory of rela-tivity.

Einstein was the first to show that the general theory was true. It was known that Mercury's path around the sun changed a little every century. Part of the change was due to the pull of gravity from the other planets. But part could not be explained.

Einstein worked out Mercury's path, using the theories of relativity. He knew that in traveling in its path, Mercury's speed varied. This would cause its mass to vary, which would cause the path to change. His figures showed that Mercury's path should move exactly the amount that it did. This not only explained Mercury's changing path, which had long puzzled men, but showed that the general theory of relativity was true.

We will return to our imaginary elevator and go

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for another ride. This time we will be out in space, beyond the pull of gravity. We will have a rope at-tached to the top, pulling the car upward.

Now imagine that a ray of light comes through a hole in the front of the elevator. It enters higher than where it hits the back wall, because in the time it took to cross the car, the elevator moved up.

All those in the car are surprised at what they seea ray of light bending! It makes no difference now whether they are on Earth or in space. There can be no doubt. They saw a ray of light bend as it passed through the elevator. Light can be bent by gravity or by the force of changing motion.

Einstein went further with this idea. He agreed that light could be bent by gravity or by changing motion. But he was not satisfied with the idea of gravity as a force that reached out, held light, and bent it. He suggested a new way to think of gravity. He said that gravity actually changes the shape of space, putting hills and valleys in space. Think of space as a large, thin sheet of rubber. Think of the sun as a ball. When you put the ball on the rubber sheet, it pulls the rubber down. If you were to roll a smaller ball along the sheet, it would roll toward the valley caused by the larger ball. In the same way, as the light travels near the sun, the path of the light follows space shaped by the sun's gravity.

How could it be shown that light is bent when it passes through space that has been bent by grav-ity? Einstein described a possible way. First, take a picture of a star so that its position is known in re-

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lation to other stars. Then, when the Earth hajjj moved so that the star can be seen on the edge


"When a man sits with a pretty girl for an horn: it seems to him a minute. But let him sit on a hot stove for only a minute, and it is longer than an hour. That is relativity!"

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8 Atoms

Probably no one learns about atoms without ex-periencing a great feeling of wonder. It is hard to imagine that all things, living and dead, big and small, are made of atoms too small to be seen. And the thought that there is a busy little world within each atom is even more wonderful to consider.

There are three leading kinds of "citizens" in the world within the atom. They are the protons, the neutrons and the electrons. The number of these particles within the atom determines the weight and chemical character of the atom. Two of the particles, the protons and the neutrons, are found only in the nucleus, the very tiny, very heavy cen-ter of the atom. They both have about the same weight. To determine the relative weight of dif-j 72

Atoms

ferent atoms, which are much too light to be actu-ally weighed, the protons and neutrons are considered one atomic weight each. Thus an atom with eight protons and eight neutrons in its nucleus has an atomic weight of sixteen.

The difference between the protons and the neu-trons is the electric charge on each. The proton has a positive electric charge. This means that it is pulled by a negative charge and pushed away by another positive charge. The neutron has no elec-tric charge at all.

Although all the weight of the atom is found within the nucleus, the nucleus is only a very small part of the ato

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Melvin Berger - Advances of Modern Science