Doctor’s Casebook – by Dr Keith Souter – The genius of scientist Louis Pasteur is still with us today

Last week I talked about Lady Mary Wortley-Montagu, one of the early pioneers of immunology. In 1717 she introduced variolation to this country from Turkey. This was an early form of inoculation against smallpox and was the best we had until 1796, when Dr Edward Jenner discovered vaccination.

Jenner noticed that milkmaids who caught the mild illness of cowpox rarely went on to contract the potentially deadly smallpox. Deducing that cowpox gave protection he experimented with inoculation and published his historical paper in 1798. The word ‘vaccine, from the Latin ‘vacca’ for cow was coined for the first time.

The next significant figure was Louis Pasteur (1822-1895), a French chemist who discovered that microbes were responsible for making wine turn sour and that they did this by turning alcohol into vinegar. This led him to develop the process of pasteurization, which was named after him, in which bacteria are destroyed by heating beverages and then allowing them to cool. We still use this widely today in the dairy industry, because milk is an organic and nutrient rich liquid that is extremely susceptible to the growth of micro-organisms. Indeed, nearly every liquid you buy will have been pasteurised to prevent the growth of bacteria, thereby making them safe to consume.

Pasteur then turned his attention to the study of disease. His researches led him to conclude that micro-organisms were the cause of various infectious diseases. He proposed the Germ Theory and such was his standing in science that within a short period of time it was widely accepted. For the first time we were given a scientific understanding of infections.

In 1865 building on the work of Agostino Bassi de Lodi, he saved the silk industry by showing that if the parasite that caused the disease ‘pebrine’ in the silkworms could be eliminated then the disease would disappear.

He went on to develop vaccine therapy, producing a vaccine against chicken cholera in 1879. Further research led to him developing vaccines against anthrax, smallpox, TB, cholera and rabies. Undoubtedly, he was one of the  true giants of modern science.