In the mid and late 19th century, scientists conducted medical researches in examining the microorganisms causing deadly diseases in human beings. They were more than explorers. In other words, they were healers who discovered remedies for many illnesses caused by organisms invisible to the naked eye. Initially, scientists involved in such researches, had to invent their own research techniques, learning ways and methods to cultivate germ cultures and prove their observations by trial and error. What was lacking was a basic systematic research approach whereby organisms responsible for dreaded diseases could be discovered easily.
At last, one man who worked with pure logic was able to devise techniques by which future researches could be conducted in an appropriate manner. It was none other than Dr. Robert Koch – a man who showed the way to medical researchers.
German folk doctor Robert Koch lived a very fruitful and symbolic life, which began on December 11, 1843 in a tiny German town within the upper Harz Mountains of Clausthal – Zellerfeld, Hanover. He was one among 13 children. His father was a mining official.
When Robert was five, he told his parents, “I can read.” His parents were surprised at the kid’s words. In fact, little Robert taught himself to read with the aid of newspapers. This act foreshadowed the intelligence and methodical perseverance of Robert in his later life. While growing up, he displayed an interest in chess and a flair for natural history. Young Robert used to spend much of his time in wandering and collecting natural objects like minerals, plants, small animals, as well as insects and lichens. His ambition was to become a great explorer. Like his father, he had a strong urge to travel.
Robert began his educational career from the local high school, called Gymnasium. He was scholarly and Biology was his favorite subject. He was also interested in literature and especially influenced by Johann Goethe.
Robert strongly desired to become an explorer but destiny had something else in store for him. After his preliminary education, he enrolled in Gottingen University to study medicine in 1862. There he studied botany, physics, and mathematics. Robert was very much influenced by Jacob Henle, the professor of Anatomy. Henle’s book, describing infectious diseases caused by living organisms called Parasites, had great impact on Robert. He also got a chance to meet eminent scientists of those days, Friedrich Wohler and Wilhelm Krause. Friedrich Wohler, the chemist, was first to synthesize an organic compound like urea, from an inorganic substance in 1828. While studying medicine, Robert made up his mind to be a skilled doctor and serve mankind through his works. Shortly after his graduation in 1866, he joined the Hamburg General Hospital as an intern.
At Hamburg, he came in contact with Emmy Fratz. He fell in love with her and soon tied the nuptial knot. She bore him their only daughter, Gertrud, who later married a doctor. Robert and Emmy’s marriage lasted for more than 25 years, and ended in 1893. Dr. Koch married Hedwig Freiberg, the second time, at the age of 50.
After a brief tenure at the Hamburg General Hospital, he worked at an institute for mentally retarded children for a few months. Prior to this, Koch had stayed in Berlin for six months to study chemistry, where he met Professor Virchow and was greatly influenced by his works.
As a physician, Koch practised in various provincial towns during the initial stage of his career. First at Langenhagen and thereafter, at Rackwitz, the province of Posen in 1869.
After passing his District Medical Officer’s Examination, he served in the Army as a medical officer throughout the Franco-Prussian War. In 1872, Dr. Koch was designated as a District Medical Officer at Wollstein, Prussia. He worked there till 1880. This was the most important phase in his life. He carried out the epoch-making researches that were the beginning of his long voyage in the scientific world. He began studying substances through a magnifying glass. One of the most cherished moments in his life was when his wife Emmy gifted him a microscope on his 28th birthday. This greatly facilitated his researches. As a physician, he was busy and successful. But his professional activities did not deter him from developing interests in subjects like bacteriology, archeology, and anthropology and also a new field of occupational diseases like lead poisoning.
In those days, bacteriology was the newly emerging field of science. Hence, initially Koch had to overcome teething problems due to lack of scientific equipments. Moreover, he was cut off entirely from libraries and contacts with other scientific researchers. His home – a four room flat – was his laboratory. Apart from the microscope, the equipments were procured from his own meager resources. Despite paucity of funds and lack of scientific equipment, he made remarkable progress in his research work.
During this period he had observed that the mortality rate of cattle was very high in Europe. He decided to devote himself to finding the cause behind the fatal disease suffered by other warm-blooded animals. Koch’s first major breakthrough in bacteriology occurred in 1870s, when he discovered bacillus responsible for anthrax.
The results of this painstaking work were demonstrated by Koch to Ferdinand Cohn, Professor of Botany at the University of Breslau. Cohn called a meeting of other scientists, including the great German pathologist Julius Friedrich, Professor Friedrich Cohnheim and bacteriologist Paul Ehrlich, the founder of modern immunology among others to witness this demonstration on Pathological Anatomy. Both Cohn and Cohnheim appreciated Koch’s pioneering work. In 1876, Cohn published Koch’s findings in the popular medical journal – Beitrage Zur Biolugie Der Pflanzen, of which he was the editor. This brought Koch in the limelight. Soon further recognition was to follow. He was the first scientist to demonstrate that “mysterious substances do not cause infectious diseases but specific substances called microbes were the causative agents of specific disease”. These agents were later named Bacteria.
His findings created a revolution in the world of science, which also brought to light the pathogenic nature of certain microbes or microorganisms, as their contributory role in human diseases was an unsolved question since their discovery by Louis Pasteur.
Now, Koch was famous but still without adequate quarters or equipped laboratory conditions for his research work. In 1880, he was appointed a member of the Reichs-Gesundheitsamt – Imperial Health Bureau, in Berlin. At first, he was provided with a narrow, badly ventilated room as a laboratory. Later, he was lucky to get a well-equipped laboratory. He worked there with his assistants, Loeffler, Gaffky and others; and continued to refine the bacteriological methods he had used in Wollstein. Berlin became his mainstay, where he carried out most of his research for the rest of his career. During this period, Koch developed postulates, the four criteria that assist in distinguishing microbes from one another. These postulates have been validated and much sought after in present day researches. He also invented a new method, Reinkulturen, which was the cultivation of pure bacterial cultures on solid media, such as potato and on nutrient agar kept in a special kind of flat dish invented by his colleague Petri and called Petridish.
Now, Koch had the tools and the techniques to carry out investigations in the field of his interest. He had a doctor’s desire to cure and the scientist’s eagerness to explore the unknown. In 1881, he concentrated on tuberculosis, the fatal disease of those days, due to ignorance and poor hygienic conditions that people lived in. The following year he announced the way he had isolated bacillus responsible for tuberculosis.
He published his work on this bacillus that was confirmed and acclaimed by medical researchers throughout the world. Following this discovery, he was appointed leader of the German Cholera Commission to investigate the epidemic of cholera in Egypt and India. He traveled to these countries and discovered Vibrio cholorae, the causative agent of cholera. He charted the rules for control of cholera epidemic that were approved by German authorities in 1893. These rules are effective and in use even today.
The Government of Germany honored Koch’s significant contribution in 1891 by appointing him Director of Berlin’s Institute for Infectious Disorders in 1891. Koch retained the post till 1904.
In later years, Dr. Koch went on to study tropical diseases of the East and West Africa. He had achieved the heights of fame and was honored with several awards and prizes. His invaluable contribution got him the prestigious Nobel Prize for Medicine in 1905.
Dr. Robert Koch made scientific research the only mission of his life. He lived for more than 15 years than that contemporary Louis Pasteur, another great microbiologist of that era. Koch died on May 27, 1910, of a heart attack at the German Health Resort, in Baden-Baden. Today, apart from his other inventions, his Postulates guide those working in the field of microbiology. The rich legacy of his works has placed his name among those who dedicated their lives for the well being of human race.
Our quest for knowledge has led us to two frontiers – space, and the world of microscopic life. Dr. Robert Koch, the German Bacteriologist, chose the latter and set it up on its feet, turning it into an exact science. He endeavored to take up the arduous task of probing the microscopic world of bacteria. He cleared the doubts pertaining to microorganisms, which were hitherto unknown and shrouded in mystery.
In the late 19th century, two of the most dangerous killer diseases were King Cholera and White Death–Tuberculosis. Koch achieved remarkable breakthroughs in the fight against these diseases, and the world recognized him as The Father of Modern Bacteriology. He isolated many diseases – bacteria and animal vectors of a number of diseases. The weakening of the mighty human at the hands of the invisible bacteria appalled him. His in-vitro and in-vivo researches helped human kind’s ascent towards healthier life.
Today, Koch’s Postulates serve as an infallible guide for bacteriologists and researchers alike, expanding new vistas of knowledge, reminding us of his luminous personality.
December 11, 1843 Birth of Robert Koch in Hanover, Germany.
1862 He went to the University of Gottingen to study medicine.
1866 Received his M.D. degree from the University of Gottingen.
1867 After internship at Hamburg General Hospital, he started General practice at Langenhagen.
1869 Practiced at Rackwitz. Passed his District Medical Officer’s Examination.
1870 He volunteered for service in the Franco-Prussian war.
1872 Appointed as the District Medical Officer in a small town of Bomst.
1876 Discovered the bacillus responsible for Anthrax disease.
1880 Appointed a member of the Imperial Health Bureau in Berlin.
1882 Discovered the bacillus responsible for Tuberculosis disease.
1883 Was sent to Egypt as leader of the German Cholera Commission.
Discovered the vibrio responsible for causing Cholera.
1893 He formulated the rules for the control of epidemics of Cholera and other diseases, which got approval by the authorities in Germany
.
1885 Appointed as a Professor and Director of Hygiene in the University of Berlin.
1891 Became Director of Berlin’s Institute for Infectious Disorders.
1901 His declaration at the International Medical Congress on Tuberculosis in London : The bacilli causing human and bovine tuberculosis are not identical.
1904 He retired from the Directorship.
May 27, 1910 Death of Dr. Robert Koch at Baden-Baden, in Germany.
ANTHRAX
Robert Koch began his scientific studies at Wollstein with a small laboratory, equipped with a microscope, a microtome (an instrument that cuts thin slices or cross section of objects that are to be seen under the microscope) and a self-made incubator. At that time, new and fundamental discoveries were rocking the scientific and medical worlds. His contemporary French scientist Louis Pasteur had touched the height of the microbiological world with his path-breaking discoveries. In such an exciting period, young Dr. Koch decided to conduct research into the cause of diseases, rather than treating patients suffering from them.
Koch was lucky to venture into an area of research he desired, in Wollstein. The farmers of his district were badly affected by the diseased animals, the diseases that Louis Pasteur had tackled earlier. It was Anthrax – the infectious fatal disease attacking farm animals and in some cases, even human beings. The causative agent of this disease, Bacillus Anthracis had been identified in the blood of affected animals or human beings. But there was a confusion whether this bacillus was the true causative agent. Even after the infected animals were removed from their places, those places were found to possess infection for several years, which was mysterious. The farmers were depressed. They appealed to Koch to find a way out.
Koch began his study by collecting blood samples from carcasses of cows that had died of anthrax. Louis Pasteur had discovered a vaccine for anthrax that was an effective cure in many cases, but still not a sure method for its prevention. Koch studied the entire life cycle of Bacillus Anthracis. He wondered as to how the microbes survived icy winters and lived to kill animals the next spring. Koch cultivated the anthrax organisms in suitable media on microscope slides. He demonstrated their growth into long filaments, and discovered the formation within them of oval; translucent bodies called dormant spores.
He chose mice to test and experimented on it, in-vitro. He lucidly explained his findings : why the infection persisted over a long period despite removal of the carcass of the infected animals, that the bacillus could generate spores, which could survive for a long time. He further experimented the nutrient fluid containing the anthrax bacilli at various incubation temperatures. He completely dried out the solution, subjected it to extreme degrees of heat and cold. When he observed the bacilli under the microscope, they had shrunk and slowly contracted into individual glassy spheres. They stayed in this dormant phase known as spores for months. When Koch placed them into a warm nutrient solution, the glassy spheres immediately started to turn back into their original rod-like shape and became active to infect another animal -again. Koch was overwhelmed by these findings. This was the first time in history that such a life cycle had been observed under the controlled in–vitro conditions!
Koch demonstrated his findings to Professor Ferdinand Cohn, an eminent botanist who worked with plant spores. He confirmed Koch’s findings. Julius Cohnheim, a noted pathologist who was deeply impressed by Koch’s discovery, expressed : “It leaves nothing more to be proved. I regard it as the greatest discovery ever made with bacteria and I believe that this is not the last time that this young Robert Koch will surprise and shame us by the brilliance of his investigations.”
PURE BACTERIAL CULTURE
After the success of anthrax research, in 1877, Koch published an important paper on investigation, preservation and photographing of bacteria. The next year, he summarized his experiments on the etiology of wound infection. He experimented and demonstrated that the animal body is an excellent apparatus for cultivating the bacteria. Elsewhere in the world, other researchers were gratefully adopting Koch’s pure culture techniques.
Soon after his appointment to the Imperial Health Board in Berlin, he realized that the study of bacteria must be pursued under absolutely controlled conditions. He was not satisfied with his hanging drop slide method.
This discovery of Koch was an accident, the result of his forgetfulness. Once it so happened that someone had left a boiled potato, a part of his lunch, on Koch’s laboratory desk. When Koch arrived at the laboratory next morning, he noticed the potato and was perhaps annoyed at the negligence of his staff. He was going to throwthe potato out of the window and when he saw that the potato was carrying some tiny colored specks. His curiosity led him to a question : why were there so many different colors ?
He studied the bits of potato microscopically and found that each spot contained a colony of active germs. Every point of infection had its own type of microbe, even though there was no contamination ! Koch found the way to grow bacteria in a pure form. There was a maximum probability for development of contamination in liquid cultures. Koch realized that bacteria grown on a solid nutrient media remained pure. Koch and his assistants, including Petri, the inventor of Petridish, experimented with other foods and nutrient materials. Finally, they succeeded in developing a gelatin beef–broth solution on which all types of bacterial cultures could grow and thrive. It was a major breakthrough in bacteriology. Bacteria no longer needed to be developed in an animal host or guinea pig. It was substituted by the new alternative, now known as agar, which is used in every biological laboratory today. Koch’s discovery brought an end to cruelty towards animals and revolutionized bacteriology making it an exact science.
KOCH’S POSTULATES : GUIDELINES FOR MICROBIOLOGISTS
Following the introduction of advanced methods by which the bacteria could be cultivated, detected and identified in a pure culture, Koch worked out a systematic method for biological research. He formulated a set of rules in 1882, which are known as Koch’s Postulates. These are four postulates, which became a guide for bacterial researches :
• The researcher must show that same type of microbe exists in every case of the disease studied.
• The researcher must be able to isolate the microbe and grow it in a pure culture.
• The researcher must be able to inject this culture into susceptible test animal or guinea pig and demonstrate the infection of the disease once again.
• The researcher must be able to isolate the microbes from the infected animals, grow a new culture, and repeat the entire process.
Koch followed these postulates to identify specific bacilli causing the specific disease, like Mycobacterium causing tuberculosis, Vibrio cholorae causing cholera, Salmonella typhi causing typhoid, Streptococcus pneumoniae causing pneumonia, Neiserria meningitides causing meningitis, Clostridium tetani causing tetanus and host of other bacteria including Staphylococci, Streptococci and Gonococci.
TUBERCULOSIS
Koch, now recognized as a scientific investigator of the first rank, moved rapidly and concentrated on the study of tuberculosis, with the main aim of isolating it and getting to the root cause. In those days, tuberculosis was a major disease affecting public health in Europe. The mortality rate was so high that one out of seven succumbed to this dreadful disease, called white death.
No one had ever seen the microbe that caused the disease; it was mistakenly believed, even by some doctors, that there was no microbe causing tuberculosis. Only Koch firmly believed that every disease had to have its own specific cause. To prove his belief, he chose tuberculosis. He studied the bits of infected lungs from tuberculosis victims, under the most powerful microscopes available at that time. He wanted desperately to find out the germ itself, but was unable to discover it. He sorted out the problem by using dyes, hoping to color germs. Paul Ehrlich, who later discovered the cure for syphilis – another dreadful disease, was one of his collaborators. Paul was a man who had spent a lifetime in using dyes to stain animal tissues as well as bacteria. He helped Koch to design a dye that would attach itself to one type of germ alone. Eventually, the bacillus was isolated and identified. A difficulty arose when albeit for some time it seemed impossible to grow the organism in pure culture. At last, with his exceptional skills, Koch overcame all the hurdles and succeeded in isolating the organism believed to be the cause of all forms of tuberculosis. He announced his epoch-making discovery on March 24, 1882, before the Physiological Society of Berlin, which later published under the title ‘The Etiology of Tuberculosis.’ This valuable document served as an invaluable guideline and went a long way in keeping in check the epidemic of this dreadful disease in various countries.
After eight years, in November 1890, he stunned the world by announcing that he had invented an effective cure for tuberculosis. He named the newly invented substance as tuberculin. Unfortunately his venture boomeranged. Many patients collapsed following injection of large unmeasured doses that were given to them by mistake. This brought him much discredit, but all this was only a passing phase. However, his attempt was not a total failure. Later, it was proved that tuberculin had extensive applications in the diagnosis of tuberculosis. Tuberculosis was insurmountable until the middle of the 20th century as more refined drugs had to developed. As per latest research, Tuberculosis is also linked with HIV . A person having HIV becomes 30 times more vulnerable to tuberculosis, which in turn accelerate AIDS disease.
CHOLERA
After his initial success in isolating and determining the cause of tuberculosis, Dr. Koch shifted his concentration to the problems related to other diseases. Meanwhile, the disease that was causing havoc in the East threatened to enter into Europe. To nip it in the bud, the German Government appointed a commission presided by Koch to Egypt and India, where the cholera epidemic had broken out. Although Koch was frustrated by the cessation of the epidemic, he worked under difficult conditions in the dangerous tropical areas. Soon he found out that the culprit spreading the epidemic was Vibrio cholorae, a comma shaped organism and traced it to its infective source – polluted water. This was a crucial discovery as the disease puzzled the scientists and researchers over the years. Koch suggested that the disease could be controlled, perhaps even eradicated if and only if the water supplied was clean and stored in hygienic conditions. During his visits to Egypt and India, he also discovered amoebae, an organism responsible for dysentery, and the bacillus causing the ailment opthalmia, an inflammation of the eye – the diseases, commonly found among the natives of these geographical regions.
OTHER DISCOVERIES
The work of cholera was followed by a brilliant investigation of bubonic plague. In 1897, at the invitation of the British colonial rulers, Koch visited India again in order to find out the cause of epidemic of plague, in Calcutta. After extensive studies, he proved that humans caught it from a flea that resided in infected rats. The world knew for the first time that rats transmitted the plague. He became occupied from 1891 to 1899 with investigations into many other diseases hazardous to human beings and animals alike. In 1901, he stated before the International Medical Congress on Tuberculosis in London that the bacilli that caused human and bovine tuberculosis were not identical. His statement furthered much controversy and opposition at that time, but present day investigations have proved Koch’s view as the right one.
After three years, he went to South Africa to study East Coast fever of cattle. He made important observations on this disease as well as on pathogenic species Babesia and Trypanosoma and on Tick borne spirochaetosis. He demonstrated that African sleeping sickness is transmitted by the tsetse fly. Cattle Rinderpest in South Africa, Javanese malaria, Leprosy and Texas fever were some of the diseases whose microbes he discovered and identified under his microscope. Koch had formulated a technique for microbe hunting that was almost safe. It was his gentleness and kindness that he taught and passed his knowledge to every researcher; even the newcomers, who visited his laboratory.
Dr. Robert Koch was conferred many awards, commendations and honors during his lifetime. His pioneering work on cholera brought him an award of DM 100,000 (German Marks) from the Government of Germany. He held the directorship of the Institute of Hygiene in the University of Berlin in 1885, and also appointed as the director of the Institute for Infectious Diseases in 1891. He became the Brigadier General Class I of Berlin in 1890.
He received honorary doctorates from the Universities of Heidelberg and Bologna. He was bestowed with honorary citizenships of Berlin, Wollstein and his native Clausthal – Zellerfeld. He was offered the honorary memberships of learned societies and academies in Berlin, Posen, Vienna, Naples, Peru and New York. Several international scientific institutes including the French Academy of Sciences and the Royal Society of London conferred upon him honorary fellowships.
Koch was awarded the German Order of the Crown, the Grand Cross, the German Order of the Red Eagle. For the first time, such a high distinction was bestowed upon a person from the medical fraternity. Moreover, he was also honored by the governments of Russia and Turkey with their respective orders. In 1906, the German Emperor honored him with the prestigious title of Prussian Order of Merit.
The greatest honor bestowed upon Koch was in 1905, when he was awarded the prestigious Nobel Prize in Medicine for his investigations and discoveries in relation to tuberculosis.
Koch was posthumously honored in several countries where memorials in his honor were constructed. The Institute for Infectious Diseases in Berlin was renamed as the Robert Koch Institute as a tribute to this great scientist.
