List of 11 Pioneer Microbiologists of the World

List of eleven pioneer Microbiologists of the World:- 1. Antony Van Leeuwenhoek 2. Louis Pasteur 3. Robert Koch 4. Edward Jenner 5. Paul Ehrlich 6. Martinus W. Beijerinck 7. Sergei N. Winogradsky 8. Dimitri Ivanovski 9. Lazzaro Spallanzani 10. Joseph Lister 11. Alexander Fleming.

Microbiologist # 1. Antony Van Leeuwenhoek:

Antony van Leeuwenhoek (pronounced Lay-wen-hook) (1632-1723), a citizen of Delft, Holland, was not a man of great learning, but he was very ingenious. He became expert in the grinding of simple magnifying lenses.

He made these lenses of small bits of glass, polished them very carefully, and mounted each separately between two brass, copper, silver, or gold plates, to which he fastened an adjustable holder for the object to be-examined.

He constructed many of these ‘microscopes’ each containing a single lens ground by himself. The best of lenses magnified about 200 times. His microscopes were superior to any of that time.

He observed, drew and measured a large number of living organisms including bacteria and protozoa in materials such as rain water, pond and well water, and saliva and the intestinal contents of healthy subjects and communicated them to the Royal Society of London in 1683.

He is known as the father of bacteriology because it was he who first accurately described the different shapes of bacteria (coccal, bacillary and spiral) and pictured their arrangement in infected material.

Leeuwenhoek observed that very large numbers of bacteria appeared in watery infusions of animals or vegetable matter which were left to stand for a week or two at room temperature. He believed that these huge populations were the progeny of a few parental organisms, or seeds that were originally present in the materials of the infusion or had entered it from the air.

The significance of these observations was not realized then and to Leeuwenhoek the world of ‘little animalcules’ represented only a curiosity of nature. Their importance in medicine and other areas of biology came to be recognized two centuries later.

In addition to his work in microbiology, Leeuwenhoek made other contributions to medicine. He gave the first complete account of the red blood cell, demonstrated the capillary connections between-arteries and veins, and made other important anatomical observations.

In 1677, he described for the first time the spermatozoa from insects, dogs, and man. He studied the structure of the optic lens, striations in muscles, the mouth parts of insects, and the fine structure of plans. In 1680, he noticed that yeasts consist of minute globular particles.

Microbiologist # 2. Louis Pasteur:

Pasteur’s contributions are many and great. The diversity of the fields in which he used his talents is astounding. The credit of a sound and scientific beginning of microbiology goes to him, and hence he is rightly called the Founder of Microbiology.

Louis Pasteur (1822-95) was born in the village of Dole (France) on December 27, 1822. His father was a tanner. Pasteur was originally trained as a chemist, but his studies on fermentation led him to take interest in microorganisms. His discoveries revolutionized medical practice, although he never studied medicine.

1. The term ‘microbiology’, as the study of living organisms of microscopic size, was coined by Pasteur.

2. He also coined the term ‘vaccine’.

3. He concluded during the period between 1844-57.

a) That optically active compounds, such as the stereo-isomeric forms of tartaric acid and amyl alcohol, never arose from the purely chemical decomposition of sugars but were formed from them by the action of microorganisms. These were always present in fermenting liquors and increased in number as the process continued.

b) He used different forms of nutrient fluid to grow microorganisms and demonstrated that a medium suitable for one might be unsuitable for another. He advocated that for successful cultivation of microorganisms it was necessary to discover a suitable growth medium and to establish optimal conditions of temperature, acidity or alkalinity, and oxygen tension.

c) He emphasized the need for scrupulous sterilization of everything coming into contact with the material under examination and demonstrated numerous sources of contamination from air, dust and water.

He demonstrated that some organisms were not destroyed by boiling. For the sterilization of fluids he advocated heating to 120°C under pressure and for glassware the use of dry heat at 170°C. He showed the value of the cotton-wool plug for protecting material from aerial recontamination.

4. In 1860-61, he provided strong evidence to disapprove the theory of spontaneous generation.

5. In 1860-64, he gave experimental evidence that fermentation and putrefaction are effects of microbial growth.

6. In 1863-65, he developed the process of destroying bacteria, known as pasteurization. He proved that the ‘disease of wine’ could be prevented without altering the flavour by heating the wine for a short time to a temperature (55°-60°C), a little more than halfway between its freezing and boiling points.

This process (pasteurization) is employed throughout the civilized world today to preserve milk and certain other perishable foods.

7. In 1865, he was asked to attempt to find the cause of pebrine, a disease which was threatening to ruin the business of raising silkworms, an important industry in Southern France.

Pasteur succeeded in demonstrating that this silkworm disease was caused by microscopic germs — protozoa and showed that the infection could be eliminated by choosing for breeding only those worms which were free of the parasites. This discovery was one more step towards the establishment of the truth of the germs theory of disease.

8. In 1877, Koch and Pasteur demonstrated that anthrax is caused by bacteria. Pasteur grew the organisms in sterilized yeast water and kept them in the laboratory for several months, transferring them frequently to new culture fluid, in which they multiplied readily, and showed that these cultures would always cause anthrax when inoculated into healthy animals.

9. In 1880, he prevented chicken cholera by injection of live attenuated culture. He found that pure cultures of the germ of this disease which had been kept in the laboratory for some time would not kill his animals as fresh cultures did, but would merely cause a passing illness from which the chickens recovered.

Then he discovered that the animals that had recovered from a previous inoculation of weakened germs were immune, and did not succumb to the disease. Pasteur immediately perceived that it might be possible to make individuals resistant by inoculating them with the weakened (and therefore harmless) germs of a particular disease.

10. In 1880, he first successfully cultured staphylococci in liquid medium and produced abscesses by inoculating them into rabbits.

11. In 1881, he developed live attenuated anthrax vaccine.

12. In 1881, pneumococci were first noticed by Pasteur and Sternberg independently.

13. Pasteur’s crowning achievement was the successful application of the principle of vaccination to the prevention of rabies, or hydrophobia, in human beings and the development of rabies vaccine in 1885.

He did not find the germs of this disease under his microscope (now known as rabies virus) but he was able to propagate them by artificial inoculation into the brains of dogs and rabbits.

Finally he evolved a system of vaccination with weakened virus which prevented the development of this fatal disease it the inoculations are given soon after the bite of the rabid animal. He gave the first successful treatment for rabies in 1885 to a young boy bitten by a rabid dog.

14. In 1887, Pasteur and Joubert first described Clostridium septicum and called it Vibrion septique.

15. In 1888, in recognition of his incomparable achievements, the Pasteur Institute of Paris was established by public contribution during his lifetime for investigations of infectious diseases and preparation of vaccines. Acclaimed the world over for his epoch making discoveries, Pasteur died in Paris on September 28, 1895. His body lies in Pasteur Institute of Paris.

Microbiologist # 3. Robert Koch:

A bacteriologist second only to Louis Pasteur and popularly called the ‘Founder of Microbial Techniques’ was Robert Koch (1843-1910). He was born on December 11, 1843 in Germany. In 1866, he took his degree in Medicine and began a general practice in a small country town. In 1872, he took a diploma in Public Health and became interested in microscopical studies.

With a microscope given as a birthday present by his wife he set up a primitive laboratory and started his studies on microbes in relation to diseases. Later, he became the first director of the Koch Institute for infectious diseases which was established in 1891.

Koch attracted many pupils from all over the world; his pupils include famous bacteriologists as bacillus), Loeffler (discoverer of diphtheria bacillus) von Behring (discoverer of diphtheria antitoxin), Pfieffer (described Pfieffer’s bacillus and phenomenon), Kitasato (discoverer of plague bacillus), Welch (discoverer of gas gangrene bacillus), Ehrlich and Wasserman. In 1905, he was awarded the Nobel Prize in Medicine for his work on tuberculosis.

His contributions to microbiology are variegated and enormous:

1. In 1876, Robert Koch successfully isolated anthrax bacillus in pure culture, studied the formation and germination of its spores, and provided the proof of its infectiousness. This agent as the sole cause of anthrax was confirmed by Pasteur.

2. In 1877, he introduced the method of making smears of bacteria on glass slides, and of staining them with the aniline dyes. He was also the first to employ in bacteriological work the improved compound microscope of Abbe.

3. In 1878, his studies of would infections explored the role of animal experimentation in establishing the cause of bacterial infections.

4. In 1881, he described means of cultivating bacteria on solid media, thus making it possible to obtain pure cultures by transferring material from a single colony.

First he used as his growth medium pieces of potato, then 2.5-5.0% gelatin to prepare solid media fortifying them with 1% meat extract as an essential ingredient. He poured melted nutrient gelatin on glass slides and allowed them to set under a bell jar to prevent contamination.

He inoculated media using sterile needles or platinum wires dipped in suspensions to take minimum inoculum and lightly drawing lines across the medium. He also developed pour-plate method. At the suggestion of Frau Hesse, his cook, he substituted agar in place of gelatin as solidifying agent for the media. The hanging-drop method of studying bacteria as used today is a product of his genius.

5. In 1882, Koch surprised the world by announcing his discovery of tubercle bacillus (Mycobacterium tuberculosis), the causative agent of tuberculosis. He described a special staining method for detection of this organism and grew it in pure cultures in the laboratory.

He showed that animals would develop tuberculosis when inoculated with pure cultures of this organism, and recovered the identical organisms from the diseased tissues of the animals. The discovery of the tubercle bacillus made him internationally famous and the bacillus was called Koch’s bacillus and tuberculosis, Koch’s disease

6. In 1883 he discovered the causative agents of cholera (Vibrio cholerae), Egyptian ophthalmia (pink eye) and Koch Week’s bacillus.

7. In 1884, Koch expounded the postulates or laws by which an organism may be proved to be the cause of a particular disease. These are known as Koch’s postulates. He showed how he had fulfilled these laws in his own studies on the causation of tuberculosis.

He also discovered tuberculin a substance in cultures of tubercle bacilli that causes a specific reaction when injected into a tuberculous individual. He advocated use of tuberculin in the treatment of tuberculosis. But unfortunately it was a grievous error committed by him.

8. Koch continued his work on tuberculosis with respect to tuberculin reactivity and in 1890-91, he showed how a normal guinea-pig and an already infected guinea-pig behaved differently to an infection with tubercle bacillus. This is known as Koch’s phenomenon.

9. From 1885-90 Koch studies various organisms present in water, soil and air and their relation in prevention of disease.

10. He invented the hot air oven and steam sterilizer, basic tools in any microbiology laboratory. He developed methods for testing antiseptics and to distinguish between bacteriostatic and bactericidal concentrations.

Microbiologist # 4. Edward Jenner:

Edward Jenner (1749-1823) was born in Berkeley in 1749. Orphaned before he was 5-years-old, his brothers and sister set him on a career of medicine. He completed his training with the great surgeon John Hunter in London.

He introduced the modern method of vaccination to prevent smallpox. He observed that milkmaids who contracted cowpox or vaccinia while milking were subsequently immune to smallpox. On May 14, 1796 he devised a brave experiment.

He performed a vaccination against smallpox by transferring material from a cowpox pustule on the hand of a milkmaid, Sarah Nelmes, to the arm of a small boy named James Phipps his gardener s son. Six weeks later the boy was inoculated with smallpox.

He failed to develop the disease. By 1798 Jenner published his results in 23 cases and by 1800 about 6000 persons had been inoculated with cowpox to prevent smallpox. The terms vaccine and vaccination were first used by Pasteur out of deference to Jenner.

In 1967 the World Health Organisation masterminded final global plan to eradicate smallpox. Success was announced in 1980 with the declaration Smallpox is dead. Thanks to Jenner.

Edward Jenner’s discovery has now been developed into one of the most important parts of modern medicine-Immunology. This science helps us to treat many infectious diseases, and to understand transplantation, allergies and diseases such as rheumatoid arthritis and AIDS.

Jenner made several other important contributions to medicine. He was probably the first to associate angina with hardening of the arteries. He also described rheumatic hear, disease and purified important medicines.

Edward Jenner has also become in other field of science. He was made a follow of the Royal Society in 1789 for correctly described the curious nesting behaviour of cuckoos. He was also one of the first to publish convincing evidence that some species of birds migrated to other countries in the winter (many believed they hibernated).

Together with John Hunter, he studied the hibernation of mammals such as hedgehogs and dormice. Edward Jenner was probably the first person to fly a balloon in Britain Filled with hydrogen and launched from Berkeley Castle, it travelled 24 miles. A skilled geologist and fossil-hunter, Jenner discovered the first Plesiosaurus fossil on nearby Stinchcombe Hill.

Jenner’s home is now dedicated to the memory of the man and his work. His study remains much as it was the day he died in 1823. In its peaceful garden is the thatched hut where he vaccinated the poor, free of charge. Grape vines that he planted still crop heavily.

Microbiologist # 5. Paul Ehrlich:

Paul Ehrlich (1854-1915), an outstanding German scientist and genius of extraordinary activity, added a great mass to our knowledge of medical science, and a large number of technical methods he proposed are now in daily use in microbiological and chemical laboratories.

1. In 1879, he applied stains to cells and tissues for the purpose of revealing their function.

2. In 1882, he reported the acid-fastness of tubercle bacillus.

3. From 1890-1900 he did important research in immunology. He soon found that the specific effect of immune serum could be demonstrated in vivo and in vitro and introduced methods of standardizing toxin and antitoxin. To him goes the credit of minimum lethal dose.

4. In 1898, he proposed side chain theory of antibody production.

5. In 1909, he introduced salvarsan, an arsenical compound, sometimes called the ‘magic bullet’. It was capable of destroying the spirochaete of syphilis with only moderate toxic effects. He continued his experimentation until 1912 when he announced the discovery of neosalvarsan. Thus he created a new branch of medicine known as chemotherapy.

Microbiologist # 6. Martinus W. Beijerinck:

Martinus W. Beijerinck (1851-1931) was a professor at the Delft Polytechnique School (Holland) in his later years, but was originally trained in Botany and began his carrier in Microbiology studying the microbiology of plants. He was one of the great general microbiologists who made fundamental contributions to microbial ecology and many other fields.

Following are the major contributions of Beijerinck in the field of microbiology:

1. Beijerinck’s greatest contribution to the field of microbiology was perhaps his clear formulation of the concept of the enrichment culture. Instead of isolating microorganisms from nature in a nonselective fashion, he proposed ‘selecting’ specific micro­organisms from a natural sample through the use of specific culture media and incubation conditions that favoured growth of only one type or a physiologically related group of microorganisms.

Using his enrichment culture (or “selective culture”, as he called it) technique, Beijerinck isolated the first pure culture of many soil and aquatic microorganisms, including aerobic nitrogen fixing bacteria (Azotobacter), nitrogen fixing root nodule bacteria (later named Rhizobium), sulphate-reducing and sulphur-oxidizing bacteria, Lactobacillus species, green algae, and many other microorganisms.

2. Beijerinck described the basic tenets of virology and in rightly called by many as the founder of virology. From his studies of tobacco mosaic disease, he confirmed in 1898, using selective filtration technique, that the tobacco mosaic disease was caused not by any pathogenic bacteria or toxin secreted by bacteria (as stated by Ivanowski) but by some new type of pathogenic agents, which he called “contagium vivum fluidum” (infections living fluid) and referred subsequently to it as a “virus” (poison). He also said that these infections agents (the virus) multiply only inside the living cell. (Dimitri Ivanovski discovered viruses in 1992, but failed to report his findings.)

Microbiologist # 7. Sergei N. Winogradsky:

Sergei N. Winogradsky (1856-1953), a Russian microbiologist, made many contributions to soil microbiology and is rightly called the founder of soil microbiology. He had interests similar to Beijerinck’s and successfully isolated several key bacteria for the first time.

Winogradsky lived to be almost 100, publishing many scientific papers, along with a major monograph, Microbiologic du Sol (Soil Microbiology); the latter work, a true milestone in microbiology, contained his original drawings of many of the organisms he had isolated of otherwise studied in enrichment culture or natural material during his carrier.

However, the major contributions of Winogradsky to the field of microbiology are the following:

1. Winogradsky isolated pure cultures of nitrifying bacteria and clearly demonstrated that the process of nitrification (oxidation of ammonia to nitrate) was the result of bacterial action.

2. He studied in 1887 the oxidation of H₂S by sulphur oxidizing bacteria directly in their natural habitats.

3. From his studies of sulphur oxidizing bacteria, Winogradsky developed the concept of chemolithotrophy, the oxidation of inorganic compounds resulting in the release of energy. He also concluded from his studies of the nitrifying bacteria that these organisms obtained carbon from CO₂, in air, i.e., that they were autotrophs.

Although the concepts of chemolithotrophy and autotrophy were not readily accepted by his contemporaries, we know now that the two processes are extremely important processes on Earth and can even support the growth of higher organisms.

4. Winogradsky isolated in 1893 the first nitrogen fixing bacterium (the anaerobe Clostridium pasteurianum) using enrichment culture technique and by so doing developed the concept of bacterial nitrogen fixation.

Microbiologist # 8. Dimitri Ivanovski:

Dimitri Ivanovski, a Russian botanist, is famous for his studies on mosaic disease of tobacco, a severe disease especially in Holland and Germany at his time. He was actively engaged in the investigation of this disease to find out the nature of the agent causing it.

Ivanovski repealed the experiments carried out by Adolf Mayer, and first successfully experimentally demonstrated that the tobacco mosaic disease has been caused by agents which successfully passed the Chamberland-porcelain filter that retains even the smallest bacteria.

He stated that the juice from infected tobacco plants did not loss infectivity even after passage through the filtre which, if the disease was caused by a bacterium, should have happened.

It was an important clue but, contrary to his experimental result and despite his inability to isolate any bacterium, Ivanovski still maintained that either the pathogenic bacterium’ somehow passed through the filter or a ‘toxin’ secreted by it passed through the filter and made the filtrate infectious.

Microbiologist # 9. Lazzaro Spallanzani:

Lazzaro Spallanzani (1729-1799), a forgotten giant who infact was a true precursor of modern biology and one of the “founding fathers” of microbiology, died two centuries ago.

Although he is a comparatively less known than other great scientists, many aspects of our current scientific culture are based in his inspiration. This Italian, born in Modena in 1729, was a follower of the great naturalist Antonio Vallisnieri (1661-1730) and attended lectures by the famous Laura Bassi (1711-1778).

Bassi was a full professor at the University of Bologna in the middle of the eighteenth century, and was such a extraordinary woman—who spoke several languages, possessed an unusual knowledge of mathematics, physics and natural sciences, and still had time to bear twelve children—inspired the scientific vocation of the young Spallanzani.

Triggered by these stimuli, Spallanzani became professor of natural history at the Universities of Modena and Pavia and later a researcher renowned throughout Europe by the multiplicity and curiosity of his observations. Since he was ordained by the Roman Catholic Church, he is also known by the nickname of abate Spallanzani.

Following are the significant contributions of Spallanzani in the field of science:

1. Spallanzani’s classic studies on the impossibility of spontaneous generation of life from dead matter contributed to the setting up of techniques on sterilization later perfected by Louis Pasteur. Pasteur, acknowledging the importance of these studies, hung Spallanzani’s portrait in one of the halls of his Institute at Paris.

2. Furthermore, the versatility of Spallanzani’s research contributed quite efficiently to the progress of physiology in areas as diverse as blood circulation, breathing and digestion.

3. Among his many scientific achievements, the most outstanding discoveries are by far the various contributions included in his book Experiences to Serve to the History of the Generation of Animals and Plants, which was first published in Genova, in Italian, in 1786.

The experiences described in this book arc of great interest, particularly when analyzed in the light of modern techniques such as cloning or in vitro fertilization. Among other accomplishments, these studies report the first experimental evidence that ovules are fertilized by spermatozoa.

4. Spallanzani was able to obtain embryos which “were born just as if mating had preceded their life” by means of artificial fecundations in various animals. On these bases, he tried to obtain not only hybrid animals but also imaginary beings, such as the famous onotauro, an animal supposed to be the result of breeding between a bull and a mare or a horse and a cow. He thought that “Nature always responds to questions with instructive answers”, hence he managed to learn valuable lessons even when he met with failure.

Spallazani’s scrupulous thoroughness in the performance of experiments, his wide and imaginative ability to design them, and his exquisite precaution to interpret the results were characteristics of his personality. He clearly demonstrated traits that are typical of current scientists rather than of ancient naturalists.

His method of repeating experiments several times, for instance, met with serious criticism among his contemporaries, and even the famous English surgeon John Hunter (1728-1793) was of the opinion that he multiplied unnecessarily the experiments with no known purpose.

But, such an approach, however, allowed him to reach conclusions that are still valid after centuries. However, as scientists in all ages, Spallanzani was not immune to error.

Prisoner in part of Aristotle’s ideas, he favored some wrong interpretations of the pre-formationist theory, which supported the pre-existence of the embryo before fertilization and assumed a sole animistic role for the spermatic fluid. Nevertheless, we owe to Spallanzani the first studies on reproduction which can be considered really modern.

Microbiologist # 10. Joseph Lister:

Joseph Lister (1827-1912), an English surgeon, was born at Essex (England) and died at Walmer (England). He was the son of a wealthy wine merchant namely, Joseph Jackson. Lister who developed an achromatic lens for the microscope. His parents took a great interest in their son’s education. They instructed him and sent him to Quaker schools that imphasized natural history and science.

At the age 16 his decidea medicines would be his carrier. Lister graduated from King’s College, London, and became a house surgeon at University Hospital in 1852. He was appointed as assistant to James Symes, the best surgeon of the day.

He later married Symes’s daughter. Lister enjoyed a privilege denied many scientific innovators; he saw his principles accepted during his lifetime and was honored with the title of Baronet in 1883.

He was also appointed as one of the twelve original members of the Order of Merit in 1902. A British Institution of Preventive Medicine, previously named after Edward Jenner, was renamed as Lister Institute of Preventive Medicine in 1899 in honour of Lister.

Lister was a humble, religious, and unassuming man, uninterested in financial gain or fame. After the death of his wife in 1893, he retired from surgery and al his death in 1912, was almost completely blind and deaf.

Following are the real contributions of Lister:

1. Lister’s discovery of antiseptic treatment of wounds is outstanding. As a surgeon, Lister was concerned with the high mortality rate of post-amputation patient and the high rate of gangrene after surgery.

Applying the knowledge that bacteria caused disease, and drawing from Louis Pasteur’s work that proved the existence of airborne microorganisms, Lister concluded that airborne bacteria could cause infection in surgical wounds.

Lister read about the effect of carbolic acid used on sewage bacteria in outhouses, cesspools and stable in the about the effect of carbolic acid used on sewage bacteria in outhouses, cesspools and stables in the nearby town of Carlisle, and developed an antiseptic system whereby he would spray carbolic acid in the operating room, and use it to sterilize the surgical instrument and his hand. In addition, he applied the acid and around the wound, and directly on the dressings.

Lister first used this method in 1865 while treating a compound fracture of a leg, an injury that often claimed about 60% of patients, and where amputation of a limb was usually the only treatment. The procedure was successful. Lister published his antiseptic method in The Lancet, in 1867. There was one problem carbolic acid, especially the spray, was harmful to those who came in contact with it.

However Lister found milder antiseptics and later heat-sterilized the surgical instruments. At first, the medical found community did not support Lister’s theory, but eventually his antiseptic method gained recognition and was adopted as standard procedure for treating wounds and during surgery.

Medics used Lister’s antiseptic method, which proved to be effective, during the Franco-Prussain War (1870-1871). In 1877, Lister became Professor of Surgery at King’s College, London.

2. Besides his discovery of antiseptic treatment of wounds, Lister’s achievements in the field of surgical techniques also deserve mention. During his stay at King’s College Hospital in London, he became the second man in England to operate on a brain tumour. He also developed a method of repairing ‘kneecaps’ with metal wire and improved the technique of mastectomy.

3. Lister also studied histology under William Sharpey during which time, he wrote an important paper on inflammation where he discussed the susceptibility to disease of inflammed tissue.

However some consider Lister “the father of modern antisepsis”. Listerine mouth-wash is named after him for his work in antisepsis. Also named in his honour is the bacterial genus Listeria, typified by the food-borne pathogen Listeria monocytogenes.

Microbiologist # 11. Alexander Fleming:

Alexander Fleming (1881-1955) was born to a Scottish sheep-family. He excelled in school and entered St Mary’s Hospital in London to study medicine. He was a short man, usually clad in a bow tie, who even in his celebrity never mastered the conventions of public society.

Fleming was a bacteriologist and would have remained a quiet bacteriologist had serendipity not come calling that fateful September in 1928 when he discovered penicillin, the miracle drug, from the mould Penicillium notatum. In fact, Fleming was not even the first to describe the antibacterial properties of Penicillium.

John Tindall had done so in 1875, E. Duchesne in 1896 and, likewise, D.A. Gratia in 1925. However, unlike his predecessors, Fleming recognized the significance of his findings. He would later say, “My only merit is that I did not neglect the observation and that I pursued the subject as a bacteriologist”.

The improbable chain of events that led Alexander Fleming to discover penicillin is the stuff of which scientific myths are made. Fleming had been interested in searching something that would kill pathogens ever since working on wound infections caused by staphylococci bacteria. He left a culture plate smeared with staphylococcus bacteria on his lab bench while he went on a two-week holiday.

When he returned, he noticed a clear halo surrounding the yellow-green growth of a mould that had accidentally contaminated the plate. Unknown to him, a spore of a rare variant called Penicillium notatum had drifted in from a mycology lab one floor below.

Luck would have it that Fleming had decided not to store his culture in a warm incubator, and that London was then hit by a cold spell, giving the mould a chance to grow.

Later, as the temperature rose, the staphylococcus bacteria grew like a lawn, covering the entire plate — except for the area surrounding the moldy contaminant. Seeing that halo was Fleming’s “Eureka” moment, an instant of great personal insight and deductive reasoning.

He correctly deduced that the mould must have released a substance that inhibited the growth of the bacteria. Fleming’s initial work was reported in the British Journal of Experimental Pathology.

By 1932, Fleming stopped his work on penicillin and happily provided other researchers with samples of his mould. Fleming’s work remained in relative obscurity for a decade. In 1939 a specimen of Fleming’s mould became available to a team of scientists at Oxford University led by Howard Florey. This team had technical talent, especially in a chemist named Ernst Boris Chain.

Florey, Chain and their colleagues rapidly purified penicillin in sufficient quantity and successfully treated mice that had been given lethal doses of bacteria.

They also demonstrated in later years that injections of penicillin caused miraculous recoveries in patients with a variety of infections. Pneumonia, syphilis, gonorrhea, diphtheria, scarlet fever and many other bacterial infections that once killed patients suddenly became treatable.

As deaths caused by bacterial infections plummeted, a grateful world needed a hero and Fleming become such hero. Fleming received awards and accolades in rapid succession, including a Knighthood (with Florey) in 1944 and the Nobel Prize for Medicine (with Florey and Chain) in 1945.

When Fleming died of a heart attack in 1955, he was mourned by the world and burried as a national hero in the crypt of St. Paul’s Cathedral in London. Although Fleming’s scientific findings may not have reached greatness, his singular contribution, the discovery of penicillin, changed the practice of medicine and the course of history.