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The Wonders of Scientific Discovery by  Charles R. Gibson
Table of Contents


 

 

DISCOVERIES CONCERNING OUR BODIES

Should we know our own anatomy?—Curious ideas of the Ancients—Harvey's discovery of the circulation of the blood—A large model of the human heart—Why the earliest anatomists made little progress—Scene in a graveyard—Stealing a corpse from the gallows—What led Harvey to his discovery—Mysterious spirits within the body—Discovery of "cells "—Great impetus to medical science—The human brain—Some curious ideas—Phrenology—Word-blindness—Word-deafness—Brain and personality—Brain surgery

[96] IT is remarkable how very little of his own body is known by the average man. There is an idea abroad that the less a person knows of his bodily organs the more peace of mind he will have, the argument being that the more he knows, the more will he imagine all sorts of ailments. The author's experience has been that those who know least imagine most; they picture things that could not possibly occur. If we understood really the functions of our various organs, and if we acted according to such knowledge, we should doubtless suffer less. However, our present subject is not hygiene nor yet physiology, but more properly the history of physiology; we desire to see how man came to discover the meaning of the different parts of his own anatomy.

The Ancients had some curious ideas of the functions of their different organs. They believed the mind to be situated in the kidneys, and did not connect the brain with the actions of thought. The heart was the seat of the soul, and from the heart came forth good or evil. We still use [97] such expressions as "a good heart" or "a hard heart" as being descriptive of a person's nature, but, of course, we do so only in a figurative sense. In passing, it may not be out of place to remark that in teaching the young it is a mistake to carry the symbolic idea too far. For instance, a clergyman tells the children that their hearts are hard as stone, or black with sin. The child pictures the actual heart, indeed there has been no attempt to cause it to think otherwise, the symbol becomes the reality, and to some thoughtful children the idea appears absurd, and more harm than good is done. There is no doubt that even in adults a great deal of religious doubt arises simply from mistaking symbols for realities. Symbols are of much value so long as they are recognised as symbols.

The ancient belief that the mind was located in the kidneys will explain to us such Old Testament phrases as "They had the Lord in their mouths, but not in their kidneys." In similar fashion the Ancients believed the bowels to be the seat of all tender emotions, and the spleen to be the organ of melancholy.

The great Aristotle, whose scientific dogmas were unquestioned for century after century, declared that the brain was a sort of cooling chamber through which the blood was passed in order to prevent its temperature rising too high. It is remarkable that one ancient philosopher, who lived five hundred years before the time of Christ, did declare the brain to be the seat of the mind and the source of feeling and movement, but no heed was paid to these "ridiculous notions." Very gradually it became evident that this theory was correct, yet there was little actual progress made in gaining information concerning the brain until modern times.


[Illustration]

A MODEL OF THE HUMAN HEART
THIS MODEL IS OF INTEREST IN CONNECTION WITH HARVEY'S GREAT DISCOVERY OF THE CIRCULATION OF THE BLOOD. THE INSET IN THE LEFT-HAND CORNER SHOWS THE MODEL WHEN CLOSED, AND INDICATES WHERE THE BLOOD ENTERS AND LEAVES THE HEART.

[98] Perhaps the one discovery which stands out most prominently in the mind of the average man is Harvey's discovery of the circulation of the blood. We shall see presently that there is another discovery of even wider influence, but Harvey's discovery has been of immense importance.

Before considering what led up to this great discovery made by Dr. William Harvey, who acted as physician to King Charles I, nearly three hundred years ago, it will be well to keep in mind a simple picture of the circulatory system.

In the illustration facing this page we see a large model of the human heart. The inset photograph shows the outward appearance, while the larger picture, with the interior displayed, will help to make matters quite plain to anyone who has not considered the subject. It will be observed that there are four distinct chambers in this hollow muscle which we call the heart. The lower left-hand chamber drives the blood out into those tubes or blood-vessels which we call the arteries. These arteries carry the blood to every part of the body; they branch off as they go, dividing and subdividing again and again till they terminate in thread-like tubes so very small that they cannot be seen without the aid of a microscope. From these extremely fine endings of the arteries the blood escapes and is transferred to similar thread-like tubes which are attached to the small veins, and these act as tributaries to larger veins, and so on, leading back to the top chamber on the opposite side of the heart. During this circular course the blood has carried nourishment to all parts of the body, and has also conveyed waste matter to the various organs capable of dealing with it. Therefore the bright arterial blood which set out from the left-hand side of the heart has been returned to the right-hand side as blood with [99] less nutriment and more waste matter, and has a purple colour. This venous blood passes down into the lower chamber of the right-hand side, and from there it is forced, by the contraction of the heart, into blood-vessels leading to the lungs. These blood-vessels end in similar thread-like tubes like those in the main system. The air-tubes of the lungs also end in similar fine tubes, through the thin walls of which the oxygen of the breathed air passes into chemical combination with the blood, while the waste carbonic acid passes out.

When the blood is oxygenated by the lungs it returns by blood-vessels as before, and this time to the upper chamber on the left-hand side. Thence it passes to the lower chamber on the same side, which brings our consideration back to the point from which we set out originally. It will be observed that there are two distinct systems, one from the left-hand side of the heart throughout the entire body and back to the right-hand side of the heart; the other system is from the right-hand side of the heart to the lungs and back to the left-hand side, the latter being a very much simpler system.

Long before the days of William Harvey it was known that blood flowed from the heart to the lungs and back to the heart, and it was even observed that the blood was "made thin "by the air. The discoverer of this fact writes rather sarcastically thus: "Anatomists, not very wise, begging their pardon, think that the lungs receive the I know not what smoky fumes discharged from the heart. About this, all one can say is that it pleases them, for they certainly seem to think that the same state of things exists in the heart as in the chimney, as if there were green logs in the heart which gave out smoke when burnt," Then he [100] proceeds to expound his own discovery that the blood merely returns, as he describes it, "mixed with air," and he lays emphasis upon the fact that he is not merely expounding a theory but an actual discovery which he has made by examining both dead bodies and living animals.

There was no thought of a circulatory system throughout the body; it being believed that the heart sent blood to all parts of the body where it was used up, fresh blood being continually manufactured.

We cannot blame the early anatomists for having made so little progress in their knowledge of the human body; indeed, we can blame only the Church as the cause of this ignorance. The human corpse was considered so sacred that doctors were not allowed to examine it, punishment being attached to any disobedience. It was not long before Harvey's time that the Church began to lose its power in such matters.

The early anatomists were free to examine any bones of skeletons which might be found in old and superficial burying-grounds, so that the anatomy of the skeleton was known before the physiology of the body. Two enthusiasts of those days relate how they were searching an old burial-place in Paris when they were attacked by a band of wild, hungry dogs, who had come also in search of bones, but for a different purpose. These same two anatomists found it so difficult to procure a corpse for examination that they tried to steal the body of a man who had been hanged and left on the public gallows as a warning to others. The enthusiasts made this attempt in broad daylight, but were caught when climbing the gallows, and were shut out of the city. However, they returned when night came on, and succeeded in securing their object. One of these daring [101] enthusiasts was Andreas Vesalius, who wrote a pioneer work which laid the foundations of modern anatomy and modern physiology. This book was written thirty years before William Harvey was born, and it was the work of Vesalius that formed the basis of Harvey's great discovery.

This great discovery associated with the name of Harvey was that the heart did not keep sending out newly made blood, but that the blood after passing throughout the body actually returned to the heart, from which again it went to the lungs to be revitalised, returning once more to the heart, and again throughout the body, keeping up a regular circulation.

All this seems very simple to us, but when Harvey first sought after the truth by means of vivisections he found it so difficult to trace the action that he began to think "that the motion of the heart was only to be comprehended by God." It was only with very patient study and the examination of many animals that he hit upon the truth. Anatomists knew of the presence of veins carrying dark-coloured blood, but they believed that this blood was flowing from the heart just as the bright arterial blood was, and that the body required these two different bloods to nourish it.

It is said sometimes that it was the presence of the little pocket-like valves in the veins which led Harvey to his discovery (these little valves prevent the blood passing backwards through the veins), but it seems quite clear from Harvey's own writings that it was not this which gave him the clue. He tells us that it was the great quantity of blood passing from the heart which led him to the truth. He could not account for the production of so much blood, [102] and he says: "I began to think whether there might not be a motion, as it were in a circle." When he had grasped this idea, he found that it would explain many difficulties, and he was able to prove that there was a real circulatory system, not only from the heart to the lungs and back, but also, what was much more difficult to imagine, a complete circulation throughout every part of the body.

We might say also that Harvey discovered there were no such things as mysterious spirits at work within the body. Formerly it was supposed that there were natural, vital, and animal spirits which took an active part in the work of the blood-vessels, but now this simple mechanical circulatory system cleared away the necessity for these, and gave a reasonable explanation of the blood passing through other organs such as the liver and kidneys. It was soon recognised that the blood not only carried nourishment to all parts of the body, but that it also carried the waste matter, due to the wear and tear of the tissue, to be disposed of by the lungs, the skin, the kidneys, and the liver. But for our present purpose we do not require to know any more physiology than will enable us to appreciate one or two of the most outstanding discoveries concerning our own bodies.

There is no doubt that the most far-reaching discovery was made in the nineteenth century, and this was when it was discovered that all living matter, whether vegetable or animal, is built up of microscopic particles which we call "cells." The very simplest form of living creature, such as the Foraminifera mentioned in an earlier chapter, is composed of one or more of these unit cells; minute specks of protoplasm or jelly-like substance. The human body is composed of many millions of such cells; not only [103] the soft tissue but the fibres, the nerves, and the bones. One of the greatest of anatomists has said that this discovery of the cells is "the greatest discovery in the natural sciences in modern times."

The names most prominently associated with this discovery are those of the two German physiologists Schwann and Schleiden. This great discovery is one of the triumphs of the microscope. Professor Schafer has said, in his famous address to the British Association when dealing with the origin of life, that we could never have guessed that we were formed of aggregates of cells, each possessing its own life, each cell being the direct descendant of another. "Nor could we suspect by intuition that what we term our life is not a single indivisible property, capable of being blown out with a puff like the flame of a candle; but is the aggregate of the lives of many millions of living cells of which the body is composed."

The great advance in medical science made during the nineteenth century is due to this discovery that our bodies are great colonies of living cells. One particularly interesting extension of this discovery was made in connection with our blood. We know that blood is a chemical solution containing a great deal of water with nutritious substances which have been extracted from our food, and that the solid matter in the blood is composed of red corpuscles and white corpuscles, which are, of course, only seen with the aid of the microscope. As is pretty generally known, it is the multitude of red corpuscles which gives the blood its characteristic colour, there being hundreds of red corpuscles to every white one.

It has been discovered that the chief duty of the red corpuscles is to carry oxygen to every part of the body, while [104] the blood fluid removes the waste matter (wear and tear) to the different organs which dispose of it.

Our present interest lies in the white corpuscles, for it has been discovered that these are independent living organisms. These little living cells act as scavengers within us, for on meeting any particle of solid matter in the blood they surround it and by chemical means cause it to disappear. A very interesting exhibition of these white corpuscles at work has been given by means of the cinematograph. Actual moving pictures were taken through the microscope, and when reproduced they showed these white corpuscles attacking some disease germs (microbes) which had gained access to the blood. We may regard disease as a battle between these white corpuscles and the invading germs, the final victory deciding whether the patient recovers or not, but the subject of microbes will be dealt with in the succeeding chapter.

We know that when a person has been partially paralysed through an effusion of blood into some portion of the brain the patient sometimes recovers the use of the affected parts. The thanks of such patients is due to these little white corpuscles in the blood, for they have clustered round the blood-clot which causes the trouble, and they have devoured the red corpuscles which have become encased in a clot.

When we think of the actions of such cells we must marvel at the great Mind which created these. Some German scientists have sought to minimise the marvellous powers of the cell as being due to mere complex chemical actions. In opposition to this we have the declaration of the great evolutionist, Alfred Russel Wallace, which he has made when speaking of the formation of the simple [105] cell, and how it contains all the forces which lead on to the evolution. This great thinker says: "What we must assume in this case is not merely a force. What we absolutely require is a mind far higher, greater, more powerful than any of the fragmentary minds we see around us; a mind not only adequate to direct and regulate all the forces at work in living organisms, but which is itself the source of all those other forces and energies, as well as of the more fundamental forces of the whole universe."

Before passing on to the epoch-making discovery of that invisible world of microbes, detected only with high-power microscopes, it will be of interest to consider a few things which have been discovered concerning that most interesting organ the human brain.

A very brief description of the brain may be of service in considering the discoveries concerning its operations. It is common practice to speak of a person's brains, and one is quite entitled to do so, as the main part of the brain is divided into two parts, forming a left-hand and a right-hand hemisphere. Then in addition to the main part of the brain there is a small or lesser brain situated at the back of the head and below the main hemispheres. The general appearance of the brain is that of a soft gray material, everywhere folded upon itself. One might describe it as being crumpled or creased together, producing the appearance of furrows. Beneath the gray matter there lies a great white mass of nerve 'fibres connected to the gray matter like a great array of telephone wires leading into an exchange. The gray matter is the seat of the conscious mind, and as this lies directly beneath the skull, we see how any injury to the [106] head is a serious matter. We all know that great bundles of nerves leave the brain by the spinal cord, and are distributed to all parts of the body. It may be remarked that although the early physiologists recognised that there existed nerves conveying impulses that give rise to sensations and nerves controlling motions, yet the exact differentiation of these was not discovered until the nineteenth century.

There still exists considerable mystery concerning most of the operations of the brain, but many important discoveries have been made, and the most important of these all lie within the last fifty years.

We have seen already that the Ancients did not discover that the brain was the organ of thought; probably they believed it to be too passive an organ to serve such a purpose. They were led to think of the conscious mind as existing in the blood, for when there was any great loss of blood there was also a loss of consciousness, and if the blood became poisoned the consciousness often became deranged also. As they believed the heart to be the seat of the soul, it seemed reasonable to suppose that the blood issuing from the heart should contain conscious thought. The one early anatomist already mentioned who declared the brain to be the seat of the conscious mind was ruled out of court by the other great thinkers of his day. And yet this pioneer was not merely guessing, for his conclusion was based upon his discovery that when the optic nerve leading to the brain was severed there could be no sight.

Some two hundred years later, which leaves us still about three hundred years B.C., the learned men of Alexandria carried out careful dissections of the brain, and they were able to trace the nerves of the special senses. Little progress was made for several centuries, till in A.D. 170 an [107] important discovery was made. This was that the nerves from the brain to the body were crossed; nerves leaving the right-hand side of the brain going to the left-hand side of the body, while those from the left-hand side of the brain go to the right-hand side of the body. This discovery has proved of much value, but progress at that time and right through the Middle Ages was imperceptible. We know that the practical death of Science during the Middle Ages in Europe was due to men trying to work out the meaning of things by studying only the causes instead of the phenomena and trying to trace the causes from these.

For a long time the early physiologists could not get away from the idea that the brain was a great gland, and that it secreted a subtle substance called thought, which they spoke of as "animal spirits," a sort of living flame. Not till the advent of the microscope did they abandon these ideas. It was the microscope which showed that the brain was not a gland, and did not secrete anything. Indeed, it was shown that the brain was an independent organ, having its different parts linked up to the body by nerves.

By examining the brain in this new light it was discovered that separate portions or localities were connected to definite parts of the body. No less than twenty-four distinct parts of the brain were suggested to represent as many different qualities of mind, then this was increased to thirty-eight, and later to sixty. Every individual peculiarity in a person was suggested to be due to the development of one or other of these different parts of the brain. Then arose the art of reading the natural "bumps" of the head by the phrenologist. Phrenology was firmly believed in by our fathers forty years ago. The encyclopaedias of that date devote many pages to the subject and declare it [108] to be a discovery of great importance even from a practical point of view. The attempts to read the capabilities and character from the bumps of the skull was not a charlatan profession; the originators had made a careful comparative study of skulls, but it became evident that they had not studied a sufficient number from which to draw general conclusions. The so-called mathematical bumps were found to be developed greatly in men who had no knowledge whatever of mathematics, while men who were very learned in one particular subject showed no special development of the corresponding bump. Nowadays the subject of phrenology is confined chiefly to the realms of boys' comic papers.

When the supposed discovery of phrenology was believed to be a mistaken idea, men went to the other extreme and said that the brain had no special sections, but acted as a whole, and although it was known that the brain was a double organ, it was considered that the two parts acted just as the two separate lungs act.

Then came a really great discovery. An eminent physician in France found on making a number of post-mortem examinations on the brains of persons who had died with paralysis of the right side of the body that in every case not only was the injury to the brain on the left side, but when the person had lost the power of speech there was in each case an injury to one particular area of the brain. It was clear that speech was controlled by one specific part of [109] the brain, and yet the anatomists would not accept the truth of this discovery for several years. This attitude was probably due to the fact that the new discovery seemed to corroborate the idea of phrenology, for by this time the physicians had rejected phrenology, although the general public continued to believe in the art for many years.

Other important discoveries followed and confirmed this fact concerning the special functions of different parts of the brain. One of the most interesting steps was the discovery of the cause of a very strange symptom in brain diseases known as "aphasia." One or two well-known cases will illustrate this phenomenon.

Professor W. A. Thomson, of New York, relates how he was hurriedly sent for on one occasion by an old patient whom he found to be much disturbed by a strange experience which had befallen her. The previous day she had put an advertisement in the newspapers for a waitress, and when the girls applied the next morning the lady found that she could not read their references. She then took up the printed newspaper and found that she could not read a word of it either. At first she thought that something had gone wrong with her eyesight, but she could see all around her distinctly, and she could even see to do her crochet work. As a last test she opened her Bible, thinking to turn to some part that she knew well, but she could recognise nothing in, it. She saw the pages and the printing, but the words had no meaning to her. Then she sent off post-haste for the doctor. He tried to calm her excitement as best he could, and explained to her that a small blood-vessel supplying a very small area in the brain had failed to do its duty by becoming clogged. In this particular area she had built up her knowledge of written words; all the [110] experience of words which she had acquired by means of her eyes was cut off from access for the time being. It was some consolation to her that she could still recognise spoken words; her knowledge of these had been gained by her ears, and the record of these was in a different small area of the brain. She could express herself perfectly in speech, but she could not write a single word. Unfortunately, she did not recover her power of reading; the white corpuscles of the blood failed to remove the obstacle.

The case of a young man of thirty was different, and was much more alarming. He was a clerk in a mercantile warehouse, and his people thought he had suddenly become insane, for he commenced to talk a complete gibberish, and could not understand what his friends said to him. Fortunately, it was found that he could still read and write, and to every written question he could give a perfectly intelligent answer. The poor fellow had become word-deaf through a cause similar to that in the case of word-blindness, just referred to, but in his case it was a different part of the brain which had been cut off from its blood supply. His hearing was not affected in any way; he could recognise and appreciate all sounds, but words had no meaning to him.

Such cases are fortunately rare, but there is a considerable variety of experience. One learned man, who was master of several foreign languages, suddenly found that he could not read any letter written in English, although he could read, very hesitatingly, words printed in English; English was his mother tongue. He was a most proficient French scholar, but now he could not read a word of French, although he could still speak that language. He could only make a little sense of Latin books with which he had been perfectly familiar. His Greek remained as it was, but as [111] this was the only language he could write now, he was greatly handicapped in correspondence.

From such phenomena as those just described it was discovered that in a particular part of the brain, a little mass of gray matter no larger than a hazel nut, there are registered all the multitudes of words which we know.

Another interesting discovery has been made, it being found that the word and speech centres of the majority of people are in the left hemisphere of the brain; but that in the case of left-handed people their speech centres are in the right hemisphere. What led to this discovery was the fact that in cases of paralysis, when there had been loss of speech, it had been generally the right side of the body which had been paralysed. And further, that when loss of speech accompanied paralysis of the left side of the body, in such cases it was found that the patient had been left-handed. A further study by means of post-mortem examinations showed that the speech area was in the left hemisphere of the brain of all right-handed patients, and in the right hemisphere of the brain in cases of left-handedness.

It goes without saying that we are born without the register of a single word in the brain, and that the building up of the records is a very gradual process. It is apparent that these registers are made in the particular hemisphere which controls the hand with which the child seeks to do things, and upon which it concentrates attention. It is apparent that there is a direct connection between speech and the gesture of the arms.

The large majority of us are either right-handed or left-handed, there being very few people really "ambidexterous," or able to use both hands equally well. The Japanese made an experiment of training a number of [112] children to use both hands equally, but the result was not satisfactory. It was found that no child trained in this fashion was ever so expert with either hand as a right-handed or left-handed child. No information is available as to whether there were two speech areas brought into use, indeed, so far as the author knows, this question has never been discussed.

It is patent that everything which is stored in the brain has been derived from without by way of the sensations, and it is evident that the chief gateways are the eye and the ear. Hence our difficulty in teaching the blind and the deaf. The most remarkable illustration of these facts is to be seen in the life story of Helen Keller, who, when she was still an infant of nineteen months, became blind, and deaf, and consequently dumb. The only gateways she had left were the senses of smell, taste, and touch. It would seem absolutely hopeless to get such a child to learn anything: but at the age of seven years she was taught to trace upon her hand such words as "doll" and "water." In less than a month the child could trace eighteen nouns and a few verbs, but she could only repeat the tracings made by her teacher; the child had no idea what the tracings meant. How could this meaning be shown to her? Her teacher took her to a water-pump and let her hold a mug to receive the water, and when the water flowed over on to the girl's hand she (the teacher) traced anew the word water on the palm of the child's hand. All at once the girl dropped the mug, and a bright look came into her face. She traced the word water several times on the palm of her hand, and indicated that she understood. She was so delighted with her new knowledge that she even tried to teach her pet dog the meaning of the word water by tracing the letters on its paw.

[113] Those who have not read the life-story of Hellen Keller have missed much. In the fourth year of her education we find her becoming a true scientist, writing down such questions as: "Who made the Earth and the seas and everything? What makes the Sun hot? Why does not the Earth fall; it is so large and heavy?" And so on. She not only took a most intelligent interest in things, but she succeeded in taking a University degree. Her subjects included Advanced Greek, Advanced Latin, Algebra, and Geometry, in some of which she passed with honours. However, our present interest lies in the fact that a brain may be so stored with knowledge, although the usual gateways are permanently closed. Surely this remarkable case ought to act as a stimulus to those of us who have all our gateways open.

Some of us have been trusted with fewer talents than others, but from what has been discovered concerning the brain it must be clear that we ourselves are responsible for the making of our "brains." No matter how fortunate an individual may have been in receiving a very plastic brain, we are all born with brains which contain no knowledge whatever. We are left to acquire this. It has been said—"a great personality may make a brain, but no brain can make a great personality."

The discoveries concerning the brain have enabled surgeons to make many wonderful operations. In cases of paralysis of some particular parts of the body the surgeon has been able to know exactly the area of the brain in which the disorganisation has taken place. In many such cases he has been able to diagnose that the trouble is caused by a tumour, and he has been able to open the skull at the exact spot and to remove the source of the trouble.


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