XXV. SOME GREAT NAMES IN BIOLOGY
If we were to attempt to group the names associated with the study of biology, we would find that in a general way they were connected either with discoveries of a purely scientific nature or with the benefiting of man's condition by the application of the purely scientific discoveries. The first group are necessary in a science in order that the second group may apply their work. It was necessary for men like Charles Darwin or Gregor Mendel to prove their theories before men like Luther Burbank or any of the men now working in the Department of Agriculture could benefit mankind by growing new varieties of plants. The discovery of scientific truths must be achieved before the men of modern medicine can apply these great truths to the cure or prevention of disease. Since we are most interested in discoveries which touch directly upon human life, the men of whom this chapter treats will be those who, directly or indirectly, have benefited mankind.
The Discoverers of Living Matter.—The names of a number of men living at different periods are associated with our first knowledge of cells. About the middle of the seventeenth century microscopes came into use. Through their use plant cells were first described and pictured as hollow boxes or "cells." But it was not until 1838 that two German friends, Schleiden and Schwann by name, working on plants and animals, discovered that both of these forms of life contained a jellylike substance that later came to be called protoplasm. Another German named Max Schultz in 1861 gave the name protoplasm to all living matter, and a little later still Professor Huxley, a famous Englishman, friend and champion of Charles Darwin, called attention to the physical and chemical qualities of protoplasm so that it came to be known as the chemical and physical basis of life.
Prof. Tyndall's experiment to show that if air containing germs is kept from organic substances, such substances will not decay. The box is sterilized; likewise the tubes (t) containing nutrients. Air is allowed to enter by the tubes (u), which are so made that dust is prevented from entering. A thermometer (th) records the temperature. The substances in the tubes do not decay, no matter how favorable the temperature.
Life comes from Life.—Another group of men, after years of patient experimentation, worked out the fact that life comes from other life. In ancient times it was thought that life arose spontaneously; for example, that fish or frogs arose out of the mud of the river bottoms, and that insects came from the dew or rotting meat. It was believed that bacteria arose spontaneously in water, even as late as 1876, when Professor Tyndall proved by experiment the contrary to be true.
As early as 1651 William Harvey, the court physician of Charles I of England, showed that all life came from the egg. It was much later, however, that the part played by the sperm and egg cell in fertilization was carefully worked out. It is to Harvey, too, that we owe the beginnings of our knowledge of the circulation of the blood. He showed that blood moved through tubes in the body and that the heart pumped it. He might be called the father of modern physiology as well as the father of embryology. A long list of names might be added to that of Harvey to show how gradually our knowledge of the working of the human body has been added to. At the present time we are far from knowing all the functions of the various parts of the human engine, as is shown by the number of investigators in physiology at the present time. Present-day problems have much to do with the care of the human mechanism and with its surroundings. The solution of these problems will come from applying the sciences of hygiene, preventive medicine, and sanitation.
In the preceding chapters of this book we have learned something about our bodies and their care. We have found that man is able within limitations to control his environment so as to make it better to live in. All of the scientific facts that have been of use to man in the control of disease have been found out by men who have devoted their lives in the hope that their experiments and their sacrifices of time, energy, and sometimes life itself might make for the betterment of the human race. Such men were Harvey, Jenner, Lister, Koch, and Pasteur.
Edward Jenner, the discoverer of vaccination.
Edward Jenner and Vaccination.—The civilized world owes much to Edward Jenner, the discoverer of vaccination against smallpox. Born in Berkeley, a little town of Gloucestershire, England, in 1749, as a boy he showed a strong liking for natural history. He studied medicine and also gave much time to the working out of biological problems. As early as 1775 he began to associate the disease called cowpox with that of smallpox, and gradually the idea of inoculation against this terrible scourge, which killed or disfigured hundreds of thousands every year in England alone, was worked out and applied. He believed that if the two diseases were similar, a person inoculated with the mild disease (cowpox) would after a slight attack of this disease be immune against the more deadly and loathsome smallpox. It was not until 1796 that he was able to prove his theory, as at first few people would submit to vaccination. War at this time was being waged between France and England, so that the former country, usually so quick to appreciate the value of scientific discoveries, was slow to give this method a trial. In spite of much opposition, however, by the year 1802, vaccination was practiced in most of the civilized countries of the world. At the present time the death rate in Great Britain, the home of vaccination, is less than .3 to every 1,000,000 living persons. This shows that the disease is practically wiped out in England. An interesting comparison with these figures might be made from the history of the disease in parts of Russia where vaccination is not practiced. There, thousands of deaths from smallpox occur annually. During the winter of 1913-1914 an epidemic of smallpox with more than 250 cases broke out in the city of Niagara Falls. This epidemic appears to be due to a campaign conducted by people who do not believe in vaccination. In cities and towns near by, where vaccination was practiced, no cases of smallpox occurred. Naturally if opposition to vaccination is found nowadays, Jenner had a much harder battle to fight in his day. He also had many failures, due to the imperfect methods of his time. The full worth of his discovery was not fully appreciated until long after his death, which occurred in 1823.
Louis Pasteur.
Louis Pasteur.—The one man who, in biological science, did more than any other to directly benefit mankind was Louis Pasteur. Born in 1822, in the mountains near the border of northeastern France, he spent the early part of his life as a normal boy, fond of fishing and not very partial to study. He inherited from his father, however, a fine character and grim determination, so that when he became interested in scientific pursuits he settled down to work with enthusiasm and energy.
At the age of twenty-five he became well known throughout France as a physicist. Shortly after this he became interested in the tiny plants we call bacteria, and it was in the field of bacteriology that he became most famous. First as professor at Strassburg and at Lille, later as director of scientific studies in the École Normale at Paris, he showed his interest in the application of his discoveries to human welfare.
In 1857 Pasteur showed that fermentation was due to the presence of bacteria, it having been thought up to this time that it was a purely chemical process. This discovery led to very practical ends, for France was a great wine-producing country, and with a knowledge of the cause of fermentation many of the diseases which spoiled wine were checked.
In 1865-1868 Pasteur turned his attention to a silkworm disease which threatened to wipe out the silk industry of France and Italy. He found that this disease was caused by bacteria. After a careful study of the case he made certain recommendations which, when carried out, resulted in the complete overthrow of the disease and the saving of millions of dollars to the poor people of France and Italy.
The greatest service to mankind came later in his life when he applied certain of his discoveries to the treatment of disease. First experimenting upon chickens and later with cattle, he proved that by making a virus (poison) from the germs which caused certain diseases he could reduce this virus to any desired strength. He then inoculated the animals with the virus of reduced strength, giving the inoculated animals a mild attack of the disease, and found that this made them immune from future attacks. This discovery, first applied to chicken cholera, laid the foundation for all future work in the uses of serums, vaccines, and antitoxins.
Pasteur was perhaps the best known through his study of rabies. The great Pasteur Institute, founded by popular subscriptions from all over the world, has successfully treated over 22,000 cases of rabies with a death rate of less than 1 per cent. But more than that it has been the place where Roux, a fellow worker with Pasteur, discovered the antitoxin for diphtheria which has resulted in the saving of thousands of human lives. Here also have been established the principles of inoculation against bubonic plague, lockjaw, and other germ diseases.
Pasteur died in 1895 at the age of seventy-three, "the most perfect man in the realm of science," a man beloved by his countrymen and honored by the entire world.
Robert Koch.
Robert Koch.—Another name associated with the battle against disease germs is that of Robert Koch. Born in Klausthal, Hanover, in 1843, he later became a practicing physician, and about 1880 was called to Berlin to become a member of the sanitary commission and professor in the school of medicine. In 1881 he discovered the germ that causes tuberculosis and two years later the germ that causes Asiatic cholera. His later work has been directed toward the discovery of a cure for tuberculosis and other germ diseases. As yet, however, no certain cure seems to have been found.
Lister and Antiseptic Treatment of Wounds.—A third great benefactor of mankind was Sir Joseph Lister, an Englishman who was born in 1827. As a professor of surgery he first applied antiseptics in the operating room. By means of the use of carbolic acid or other antiseptics on the surface of wounds, on instruments, and on the hands and clothing of the operating surgeons, disease germs were prevented from taking a foothold in the wounds. Thus blood poisoning was prevented. This single discovery has done more to prevent death after operations than any other of recent time.
Modern Workers on the Blood.—At the present time several names stand out among investigators on the blood. Paul Ehrlich, a German born in 1854, is justly famous for his work on the blood and its relation to immunity from certain diseases. His last great research has given to the world a specific against the dread disease syphilis.
Another name associated with the blood is that of Elias Metchnikoff, a Russian. He was born in 1845. Metchnikoff first advanced the belief that the colorless blood corpuscles, or phagocytes, did service as the sanitary police of the body. He has found that there are several different kinds of colorless corpuscles, each having somewhat different work to do. Much of the modern work done by physiologists on the blood are directly founded on the discoveries of Metchnikoff.
Charles Darwin, the grand old man of biology.
Heredity and Evolution. Charles Darwin.—There is still another important line of investigation in biology that we have not mentioned. This is the doctrine of evolution and the allied discoveries along the line of heredity. The development or evolution of plants and animals from simpler forms to the many and present complex forms of life have a practical bearing on the betterment of plants and animals, including man himself. The one name indelibly associated with the word evolution is that of Charles Darwin.
Charles Darwin was born on February 12, 1809, a son of well-to-do parents, in the pretty English village of Shrewsbury. As a boy he was very fond of out-of-door life, was a collector of birds' eggs, stamps, coins, shells, and minerals. He was an ardent fisherman, and as a young man became an expert shot. His studies, those of the English classical school, were not altogether to his liking. It is not strange, perhaps, that he was thought a very ordinary boy, because his interest in the out-of-doors led him to neglect his studies. Later he was sent to Edinburgh University to study medicine. Here the dull lectures, coupled with his intense dislike for operations, made him determine never to become a physician. But all this time he showed his intense interest in natural history and took frequent part in the discussions at the meetings of one of the student zoölogical societies.
In 1828 his father sent him to Cambridge to study for the ministry. His three years at the university were wasted so far as preparation for the ministry were concerned, but they were invaluable in shaping his future. He made the acquaintance of one or two professors who were naturalists like himself, and in their company he spent many happy hours in roaming over the countryside collecting beetles and other insects. In 1831 an event occurred which changed his career and made Darwin one of the world's greatest naturalists. He received word through one of his professional friends that the position of naturalist on her Majesty's ship Beagle was open for a trip around the world. Darwin applied for the position, was accepted, and shortly after started on an eventful five years' trip around the world. He returned to England a famous naturalist and spent the remainder of his long and busy life producing books which have done more than those of any other writer to account in a satisfactory way for the changes of form and habits of plants and animals on the earth. His theories established a foundation upon which plant and animal breeders were able to work.
His wonderful discovery of the doctrine of evolution was due not only to his information and experimental evidence, but also to an iron determination and undaunted energy. In spite of almost constant illness brought about by eyestrain, he accomplished more than most well men have done. His life should mean to us not so much the association of his name with the Origin of Species or Plants and Animals under Domestication, two of his most famous books, but rather that of a patient, courteous, and brave gentleman who struggled with true English pluck against the odds of disease and the attacks of hostile critics. He gave to the world the proofs of the theory on which we to-day base the progress of the world. Darwin lived long enough to see many of his critics turn about and come over to his beliefs. He died on the 19th of April, 1882, at seventy-four years of age.
Associated with Darwin's name we must place two other co-workers on heredity and evolution, Alfred Russel Wallace, an Englishman who independently and at about the same time reached many of the conclusions that Darwin came to, and August Weissman, a German. The latter showed that the protoplasm of the germ cells (eggs and sperms) is directly handed down from generation to generation, they being different from the other body cells from the very beginning. In 1883 a German named Boveri discovered that the chromosomes of the egg and the sperm cell were at the time of fertilization just half in number of the other cells (see page [252]) so that a fertilized egg was really a whole cell made up of two half cells, one from each parent. The chromosomes within the nucleus, we remember, are believed to be the bearers of the hereditary qualities handed down from parent to child. This discovery shows us some of the mechanics of heredity.
Applications to Plant and Animal Breeding.—Turning to the practical applications of the scientific work on the method of heredity, the name of Gregor Mendel, an Austrian monk, stands out most prominently. Mendel lived from 1822 until 1884. His work, of which we already have learned something (see page [258]), remained undiscovered until a few years ago. The application of his methods to plant and animal raising are of the utmost importance because the breeder is able to separate the qualities he desires and breed for those qualities only. Another name we have mentioned with reference to plant breeding is Hugo de Vries, the Dutchman who recently showed that in some cases plants arise as new species by sudden and great variations known as mutations. And lastly, in our own California, Luther Burbank, by careful hybridizing, is making lasting fame with his new and useful hybrid plants.
References
Conn, Biology. Silver, Burdett & Co.
Darwin, Life and Letters of Charles Darwin. Appletons.
Galton, Hereditary Genius. London (1892).
Thompson, Heredity. John Murray, London England.
Wasmann, Problem of Evolution. Kegan Paul, Trench, Trübner and Co., London, E. C.