Louis Pasteur

Louis Pasteur was a pioneering French biochemist and the first bacteriologist.  He invented pasteurization of milk, discovered bacteria are causes of fermentation, decay and disease and developed vaccines for anthrax and rabies.

Louis Pasteur (1822-1895) was the son of a tanner from Dole, in Eastern France.  He graduated from the Ecole Normale in Paris, where the comment on his diploma for chemistry was 'mediocre': possibly because his work was already too independent and original for his masters.   He soon proved the judgment wrong, in a succession of university and college posts.

Pasteur's first discoveries came after he was asked by local wine producers to investigate why wine goes sour.  He disproved the existing theory of 'spontaneous generation": that things 'went bad' because of the air.  He demonstrated that it was the result of the activity of tiny organisms.  These organisms (bacteria, or germs) were, he believed, like any other animals, and could be killed and prevented from breeding.  He invented a process of killing them by heating, called pasteurization.  It was now possible to produce, preserved and transport wine, milk and beer without them becoming undrinkable.

In 1868, Pasteur was partially paralysed, but continued with his research.  In 1881, he successfully came up with a protection for the deadly cattle and sheep disease anthrax.  He believed it was bacteria that also caused disease, and he isolated and cultivated a weakened version of those that produced anthrax.  He injected this into 25 sheep, and some days later infected them and 25 others with the full disease.  Only the 25 not treated died.  This proved those injected had developed a resistance from their contact with the weakened germs that protected them against the full germs.  Pasteur called the weakened viruses 'vaccines' in honor of Edward Jenner, who had used cow-pox (Latin name, vaccinia) to protect against smallpox in a similar way.

Pasteur turned his attention to rabies (called hydrophobia in humans), and after painstaking research produced a vaccine from the bone-marrow of infected rabbits.  He used this on 6 July 1885 on Jacob Meister, a 9 year old boy bitten by a rabid dog, and saved his life.

Pasteur created a revolution in scientific method, moving from the laboratory and tackling disease where it happened.  He did not rest content with showing what caused disease, but sought to find solutions.  He was a close friend of Joseph Lister who justly summed up Pasteur's achievement:"Truly there does not exist in this wide world an individual to whom medical science owes more than to you."