LOUIS PASTEUR  1822 - 1895  (G4, W4, Va, Vb, Vc)


Pasteur: detail, by the French painter Leon Joseph Florentin Bonnat (1833-1922) – Musée Pasteur, Institut Pasteur, Paris. Institute: from eBook of McClure’s Magazine, September 1893, (an Amercan illustrated monthly periodical), artist unknown – The Project Gutenberg. Chardonnet: by the French photographer Eugène Pirou (1841-1909), 1905. Koch: coloured version after a portrait by the photographer Frank Hancox, contained in The London Illustrated News of 1897. Ehrlich and Behring: drawings, dates and artists unknown.

xxxxxAs we have seen, it was in 1858 (Va) that the outstanding French chemist and microbiologist Louis Pasteur began to study the process of fermentation in the making of wine. He discovered that this was caused by microorganisms, and from this finding came the method known as “pasteurisation”, a controlled heating process for destroying harmful microscopic life. Further experiments convinced him that diseases were spread by germs contained in particles of dust. His theory - one of the most important contributions to medical science ever made - was proven in 1865 (Vb). It was then that, tasked with saving the French silkworm industry, he discovered that the virulent disease which was affecting the silkworms was caused by a tiny parasite. He destroyed all the infected worms and the leaves they fed on, and re-established a thriving industry based on healthy worms.

xxxxxHis germ theory of disease did not convince all. Sceptics remained for many years, and his work came in for a great deal of adverse criticism and ridicule at times. However, by the 1880s the majority of doctors and surgeons, like the Englishman Joseph Lister, were taking antiseptic precautions to stop the spread of disease carried in the atmosphere - such as boiling instruments and using chemical disinfectants. By that time, however, Pasteur had turned his attention to preventative medicine. When studying a particular disease, he told an audience in 1884, he did not think of finding a remedy but, more importantly, the means by which it could be prevented. As early as 1880, while investigating fowl cholera - a highly contagious condition - he discovered that, by employing a process similar to that used by the English physician Edward Jenner - who had discovered a vaccine against cowpox back in 1796 (G3b) - he could give the birds immunity from the disease by inoculating them with a weakened form of the germ. He concluded that the weak strain had enabled each bird to form a defence against an even more powerful attack of the disease. And this further explained why animals which had been stricken with a disease but had managed to recover from it also became immune to further attacks.

xxxxxThe following year Pasteur turned to the study of anthrax, an acute disease which is primarily a disease of grazing animals - such as cattle, sheep and horses - but can also affect humans. His rival in this field, the German bacteriologist Robert Koch had discovered the rod shaped anthrax bacilli (illustrated) and made his findings known in 1876. Pasteur experimented further with Koch’s bacilli. By subjecting them to heat over varying periods of time he eventually managed to isolate a weakened strain which could serve as a workable vaccine. Then in May 1881, having had his findings challenged by Hippolyte Rossignol, the editor of The Veterinary Press, he staged a public demonstration of this vaccine. He injected a number of sheep and cows with the attenuated (weakened) culture, and left a similar number untreated. Four weeks later he injected all the animals with a powerful anthrax culture, and within a space of three days all the untreated animals had died. By contrast, the inoculated group suffered no ill-effects and were described as being “in perfect health”.

xxxxxIn April 1882 Pasteur was elected a member of the Académie Française, and it was then that he began his research to find a preventative treatment for rabies, a deadly virus which causes inflammation of the brain in warm-blooded animals, and can be passed onto humans from bites or scratches from an infected animal. Known in humans as “hydrophobia”, it is invariably fatal. He began his investigation by studying the saliva of an animal suffering from rabies and then, by a series of injections, he established that the disease (a virus in fact) was also present in the nervous system. Then, using the dry tissue of infected animals, particularly rabbits, he eventually obtained a weakened form of the virus which he considered to be safe for injection into humans. But the test as to its safety came sooner than expected when, in July 1885, a nine-year old boy who had been bitten by a rabid dog was brought to him for treatment. Because in the case of rabies there was a delay before the virus reached the brain, it was possible to give the vaccine after the bite had occurred. However, because the vaccine had not been fully proven, Pasteur hesitated. Then eventually, in view of the boy’s condition, he carried out the injection and, against all odds, the boy survived.

xxxxxThexsuccessful production of a vaccine against rabies led directly to the founding of the Pasteur Institute in Paris, dedicated to the treatment of infectious diseases and, today, one of the most famous centres of biological research. Built with money received from public subscriptions, raised worldwide, it was opened in 1888, and Pasteur served as its director until his death in 1895. With the assistance of a well-trained team, and serving mainly in an advisory capacity, he spent the remaining years of his life searching for the means by which diseases such as septicaemia, diphtheria, tuberculosis and smallpox could be prevented by vaccination.

xxxxxPasteur died at Saint-Cloud in the western suburbs of Paris in September 1895. A national hero with many honours to his credit, he was given a state funeral at Notre Dame Cathedral and buried in a crypt at the Pasteur Institute. Pasteur, a modest man who dedicated his life to the benefit of others, was, without doubt, one of the greatest medical scientists of all time. Quite apart from his introduction of “pasteurisation”, a method which saved thousands of lives and proved of such economic benefit, and the advances he made in providing vaccines for a number of deadly diseases, his discovery of the germ theory of disease proved the single most important contribution ever made to the advancement of medical science. Today he is recognised as the man whose painstaking work saved the greatest number of human lives.

xxxxxIncidentally, Pasteur’s life was not without its hardship and tragedy. He was brought up with a mentally retarded sister, and he saw three of his five children die of infant diseases. And during his lifetime he suffered from several strokes, one of which left him partially paralysed at the age of 46. This hampered his work but never stopped it. As a dedicated Christian, he rejected Darwin’s theory of evolution and believed, on the contrary, that science brought man nearer to God. This unswerving faith sustained him throughout his life. ……

xxxxx…… Duringxhis early research Pasteur was ably assisted by the French bacteriologist Pierre Roux (1853-1933). He began working for Pasteur in 1879 and took part in developing vaccines for fowl cholera, anthrax and rabies. Later he worked on vaccines for syphilis and tetanus, and in 1889, together with the French-Swiss bacteriologist Alexandre Yersin, he discovered the diphtheria toxin. He joined the staff of the Pasteur Institute in 1888, and was the director of the Institute from 1904 until his death.

xxxxxAs we have seen, it was in the 1860s that Pasteur saved the French silk industry from extinction by finding and eradicating a harmful parasite. In the 1880s, however, the industry was again threatened. In 1878 the French chemist Hilaire de Chardonnet (1839-1924) who, ironically, had worked with Pasteur during his research into silkworms, knocked over a bottle of nitrocellulose and noticed that, due to evaporation, the contents had developed into long thin strands of fibre, very similar in strength and appearance to silk. Working with mulberry leaves - the food of the silkworm - he turned them into a cellulose pulp by using a combination of nitric and sulphuric acids and then stretched the material into fibres. In 1884 he received the first patent for artificial silk (to become known as rayon in the 1920s ), and he exhibited his invention at the Paris Exhibition of 1889. Having treated the material to reduce its flammability, he began manufacturing his “Chardonnet silk” in 1891, the first synthetic fibre to go on the market.

xxxxxMeanwhile two English chemists, Charles Cross (1855-1935) and Edward Bevan (1856-1921), having formed a partnership in 1885, set up a chemical business in London. There they carried out research into the organic compound called cellulose, and in 1892 took out a patent for an artificial silk known as viscose rayon. This was sold commercially from 1905.

xxxxxPasteur’s major rival, whom he met in London in 1881, was the German physician Robert Koch (1843-1910), one of the founders of microbiology. He and his assistants introduced the techniques for developing bacteria outside of the body - growing pure cultures of single species of bacteria in the laboratory - and this enabled them to pinpoint the bacteria responsible for a number of deadly diseases, including tuberculosis, cholera and blood poisoning. As we have seen, it was his discovery of the anthrax bacteria in the late 1870s that assisted Pasteur in providing a successful vaccine against this disease. Hexlater confirmed that fleas and rats were responsible for the transmission of bubonic plague, and that sleeping sickness was transmitted by the tsetse fly. (Discovered, in fact, by his one-time colleague, the Scottish microbiologist David Bruce (1855-1931) in 1903.)

xxxxxIn addition, Koch pioneered valuable new techniques for conducting experiments in microbiology - such as the use of dyes to sharpen the image of bacteria under the microscope  - and he laid down a set of rules, his so-called “postulates”, to determine whether a particular bacterium was the cause of a specific disease. In 1891 he was appointed director of the Prussian Institute for Infectious Diseases (later renamed the Robert Koch Institute) but, after winning the Nobel Prize for Medicine in 1905, he spent most of his time travelling to many parts of the world, studying a variety of diseases - such as malaria, cholera and sleeping sickness - and advising on ways to combat them.

xxxxxOne of Koch’s assistants was the German immunologist Emil von Behring (1854-1917). He later became professor of hygiene at Marburg University, a position he held for over 20 years. Hexannounced the discovery of antitoxins in 1890 and, aided by the Japanese bacteriologist Shibasaburo Kitasato (1852-1931), developed a serum therapy against diphtheria and tetanus. For his advances in serum therapeutics - the treatment of disease by the injection of serum from immune animals - he was awarded the first Nobel Prize in Medicine in 1901, and his vaccination techniques against diphtheria and tuberculosis earned him the title ”Children Saviour”. Inxhis development of a diphtheria serum Behring was assisted by his colleague Paul Ehrlich (1854-1915), the German bacteriologist who later developed the first antibiotic for the treatment of syphilis, and whose research into the field of chemotherapy earned him the Nobel Prize for Medicine in 1908.

xxxxxAxnumber of other bacteriologists of this period are worthy of note. The French-Swiss physician Alexandre Yersin (1863-1943) worked with Pierre Roux in the discovery of the diphtheria toxin in 1884, and in Hong Kong ten years later - along with Shibasaburo Kitasato - he discovered the bacillus responsible for the bubonic plague - later named Yersinia pestis in his honour. ThexGerman physician Arthur Nicolaier (1862-1942) discovered the tetanus bacterium in 1884, showing that the condition resulted from the contamination of open wounds with soil bacilli, and in the same year the German biologist Frederich Loffler (1852-1915), together with his countryman Edwin Klebs (1834-1913) discovered the organism that causes diphtheria (commonly known as the Klebs-Loffler bacillus) - at virtually the same time as Yersin and Roux. Later, in 1897, Loffler discovered the cause of the virulent foot and mouth disease which affects cloven-hoofed animals.


Hilaire de Chardonnet,

Robert Koch, Emil von

Behring and Paul Ehrlich


xxxxxAs we have seen, the French chemist and microbiologist Louis Pasteur began studying the process of fermentation in the making of wine in 1858 (Va), and from this research came up with the idea of “pasteurisation”, a controlled heating system for destroying harmful microscopic life. He later became convinced that diseases were spread from germs, and proved this to be the case in 1865 (Vb) while combating a serious disease in the French silkworm industry - though sceptics remained. Then in the 1880s he turned his attention to preventive medicine and, working along the lines of the English physician Edward Jenner - who had discovered a vaccine against cowpox in 1796 (G3b) - developed a vaccine for the prevention of fowl cholera. Further success came with vaccines for anthrax in 1881 - an animal disease which can also affect humans - and for the deadly virus known as rabies. In 1888 the Pasteur Institute was opened in Paris, dedicated to the treatment of infectious diseases, and Pasteur served as its first director until his death in 1895. In these later years he supervised the work by which diseases such as septicaemia, diphtheria, tuberculosis and smallpox could be prevented by vaccination. Pasteur, a modest man who spent his life in the service of others, was one of the greatest scientists of all time. Quite apart from “pasteurisation”, a method which saved thousands of lives, and the vaccines he developed for some of the most deadly diseases, his discovery of the germ theory proved the single most important contribution to the advancement of medical science.