The Year of Louis Pasteur

The Year of Louis Pasteur International Symposia

Maxime Schwartz
Director General, Institut Pasteur

Louis Pasteur was born in 1822. The year 1995 has been designated "The Year of Louis Pasteur" to mark the hundredth anniversary of his death and will be commemorated throughout the world. The events will be organized jointly by UNESCO and the Pasteur Institute to allow the scientific community to pay a tribute to one of the outstanding figures of science, a man who revolutionized the fields of biology and medicine during the second half of the 19th century.

"The year of Louis Pasteur" will include six international scientific symposia. They will address current progress in the fields of Pasteur's major discoveries, and illustrate their universal impact on biological sciences, and their applications to health, agriculture, industry and the environment.

Symposia will be held in each of the five continents of the world, in recognition of Pasteur's role as a missionary for science, in addition to being a laboratory scientist and rigorous experimentalist. Indeed, numerous other scientists from many different countries came to work with him, and he sent collaborators to all corners of the world to continue his work.

Pasteur tackled a wide variety of research problems during his career, but nevertheless the succession of advances he made now appears to be extremely logical and constitutes a coherent body of discoveries. However, his work can be divided into several areas, each of which will be addressed by one of the symposia.

In the mid1840s, the young Louis Pasteur worked on the crystallography of tartrates. He demonstrated that molecular asymmetry is a characteristic of the living world. This was undoubtedly one of the most fundamental of Pasteur's discoveries. These studies led to the analysis and understanding of the molecular interactions that govern the functioning of all living organisms. The New York symposium entitled "Stereospecificity and Molecular Recognition" deals with this theme.

The splitting of racemic tartaric acid by fermentation was the link that led Pasteur to study lactic, ethanolic, butyric, and acetic fermentations beginning in 1854. In the course of these studies, Pasteur showed that each of these fermentations resulted from the growth of a particular microbe. He went on to identify the metabolic and nutritional characteristics of these organisms, and the optimal conditions for their growth. This was also the start of germ theory, and the identification of the universal role of microorganisms in the major cycles of matter. During this work, Pasteur also laid down various rules for industrialists who required "good fermentations." This body of work was the basis for what would now be called general microbiology, and for numerous biotechnological applications. This is the theme of the symposium in Papeete, "Microbes, Environment, Biotechnology."

With these glimpses of the breadth and diversity of the microbial world, Pasteur was drawn into considering the issue of the origin of microorganisms. An impassioned and famous debate around 1860 involving many of the leading intellectuals of the period was finally ended by Pasteur's demonstration that all the experiments supporting the theory of spontaneous generation were faulty. This posed in clear terms the problems of the origin of life and subsequent evolution, which was discussed at the symposium in Rio de Janeiro, entitled "From Spontaneous Generation to Molecular Evolution."

It did not take long for Pasteur to move from studying the involvement of microorganisms in fermentation of plant products and putrefaction of animal products to investigating their possible role in infectious disease. In 1865, Pasteur started studying silk worm diseases, then chicken cholera, pig erysipelas and anthrax. For each of the diseases, Pasteur showed that a particular microorganism was responsible, and went on to analyze these microbes and their modes of transmission. This led him to complete his germ theory, and propose prophylactic guidelines which became the basis for hospital hygiene. This work was the start of medical microbiology in its largest sense and of etiology and epidemiology of infectious diseases. The symposium in Dakar, "Etiology and Pathogenesis of Infectious Disease," and that in Hanoi, "Epidemiology and Public Health," deal with these problems.

While working with chicken cholera, Pasteur noticed that a virulent strain could lose its virulence. He called this phenomenon "attenuation." Furthermore, he found that such attenuated strains could confer immunity against the disease. Thus, Pasteur discovered the principle of vaccination and set the foundations for what became the field of immunology. The discovery was rapidly applied to anthrax. The detractors and skeptics were finally convinced of the soundness of the theory by the famous field experiment at Pouilly le Fort in 1881.

In 1880, continuing the same line of research, Pasteur started to work on rabies, a disease that preoccupied and fascinated the public. Even though he could not isolate the responsible microbe, he nevertheless managed to "attenuate" it, prepare a vaccine and vaccinate uninfected and, finally, infected dogs. In 1885, he showed that it was possible to vaccinate humans who had been bitten by rabid dogs. This success was acclaimed worldwide and was the main reason for Pasteur's universal and lasting popular fame. The issue of vaccination and vaccines remains of major importance today. It is addressed by the Paris Symposium "Vaccines, One Hundred Years after Louis Pasteur."

In 1946, the Institut Pasteur commemorated the 50th anniversary of the death of its founder with a Symposium. The publication resulting from the meeting contains articles summarizing the lectures by most eminent scientists detailing the impact of Pasteur's discoveries. These articles are fascinating for every historian of science.

The last 50 years have seen a boom in biological sciences, and this progress shows no signs of abating. The collection of the six volumes of the Year of Louis Pasteur Symposia will undoubtedly give future generations an overview of this flowering of the biological sciences by describing the current state of our knowledge and the major issues remaining unresolved. Tweet