Louis Pasteur

Louis Pasteur was born on 27 December 1822 in Dole, in the Jura department, the son of the tanner Jean-Joseph Pasteur, a former soldier of the Napoleonic era, and Jeanne-Étiennette Roqui. In 1827 the family moved to Arbois, where Pasteur attended the Collège d'Arbois. He was an average pupil; his interests were fishing and drawing.

In 1843 he was admitted to the École normale supérieure in Paris. In 1849 he married Marie Laurent, daughter of the rector of the University of Strasbourg, where he was professor of chemistry. Only two of their five children reached adulthood; three died of typhoid.

Pasteur's first research concerned the crystal forms of tartrates. In 1848 he showed that tartaric acid from living sources rotates light, whereas the synthetic mixture does not, because it consists of two mirror-image forms. As dean at Lille (from 1854) he turned to fermentation; in 1857–1858 he showed that fermentation is the work of living yeasts and bacteria.

In 1859–1862 he investigated whether life can arise spontaneously. In flasks with long, curved necks, sterile nutrient broths remained unspoiled as long as dust and germs did not enter; this supported the view that micro-organisms arise from other micro-organisms. In 1862 he received the Alhumbert Prize of the Académie des sciences for this. His debate with Félix Pouchet concerned the interpretation of such experiments.

He then applied his insights. He developed the heating of wine and beer to prevent spoilage (pasteurisation), investigated the silkworm diseases pébrine and flacherie at Alès in 1865–1870, and from 1877 worked with collaborators such as Émile Roux and Charles Chamberland on vaccines against chicken cholera, anthrax and rabies. In 1888 the Institut Pasteur opened, financed partly by donations from France and abroad.

Pasteur worked in the second half of the nineteenth century, when industrialisation, urbanisation and natural science were changing healthcare. Competing explanations existed for the cause of infectious diseases, such as decay and 'miasmas', as opposed to living germs. He was not the first to point to micro-organisms as agents of disease; Agostino Bassi did so in the early nineteenth century for a silkworm disease.

Science was also a national matter. After the Franco-Prussian War (1870–1871) the rivalry between French and German researchers, according to historians, also took on a national dimension. Robert Koch showed in 1876 that the bacterium Bacillus anthracis causes anthrax; in 1881–1882 he criticised Pasteur's methods, after which a public polemic followed.

The pasteurisation of wine and beer, and later milk, reduced spoilage and made transport and storage safer. Joseph Lister developed antiseptic methods in surgery with Pasteur's work as inspiration. Pasteur's research on silkworms helped silk farming in southern France against pébrine, although the second disease, flacherie, remained hard to combat.

His vaccines spread the idea that weakened pathogens can provide protection; he gave the word 'vaccine', derived from Edward Jenner's cowpox vaccination, a general meaning. According to the surviving figures, about 350 people were treated for rabies in 1886, of whom one contracted the disease. The Institut Pasteur became a centre for research, teaching and vaccine production.

Pasteur suffered a stroke in 1868 and afterwards worked a great deal with collaborators. He died on 28 September 1895 at Villeneuve-l'Étang, near Marnes-la-Coquette. The French government decided on national funeral ceremonies; his widow declined burial in the Panthéon and chose a crypt in the Institut Pasteur, where he rests.

In 1995 the historian Gerald Geison analysed Pasteur's private laboratory notebooks and argued that his public accounts of, among other things, the 1881 anthrax trial and the first rabies treatment sometimes differed from practice. Others, among them Max Perutz, defended Pasteur. The debate concerns how differences between private and public science should be interpreted.