Jenner: When hypothesis becomes theory & the skeptics of the day – Part 1

Happy death day Edward Jenner!!

A then living Edward Jenner

January 26th 2013, marks 190 years since the death of Edward Jenner in 1823. [1]

About 30 years before that, in 1796, that same man made one of his scientific understandings a reality. Jenner, as you should all have learnt in school, discovered that by giving people cowpox, this would protect them from smallpox.

When hypothesis becomes theory

I’ve read stories over the last few weeks that range Jenner’s contributions from, the saviour of mankind to, one small part in an already understood practice. Now, it seems fairly well understood that Jenner was neither of these. He was no revolutionary or maverick, but his part was a vital step.

There is much evidence at the time, of a causal link between cowpox and smallpox. In fact, Dr John Fewster had presented a paper to the Royal Society in 1765 titled, “Cow pox and its ability to prevent smallpox”. Also, many dairy farmers of the time were aware of the link. A cattle breeder from Dorset, Benjamin Jesty, had documented inoculating his wife and two children with smallpox in 1774.

What Jenner did, his unique contribution to science, was turning the established causal relationship into a properly tested understanding. By actually attempting to infect someone with smallpox, having first given them cowpox, he finally turned the understood hypothesis into theory.

Jenner had formed a hypothesis, based on observation. He then tested his observation. Simple, right? Job done, all home to the West Country for scones, yes?

Well, no. Of course not, because the Royal Institute weren’t going to accept a single case as proof of theory. In fact Jenner had his paper, which he had informally submitted, returned to him with a note, “that if he valued his reputation already established by his paper on the cuckoo, he had better not promulgate such ideas as the use of cowpox for the prevention of smallpox”. [2]

Persistence with actual evidence

Unlike Dr. Fewster, who had presented his paper and then went no further and unlike so many quacks and pseudo-scientists, Jenner had actual evidence and persevered. Over the next two years he carried out the practice many more time, finally presenting 23 cases independently, in his “Inquiry” of 1798.

Independent publication can raise the red flag for the critical thinker and rightly so. But Jenner wasn’t rewriting understood science, he wasn’t proposing a radical change in thinking. He just took the next step. He’d followed the mantra of the scientific community at the time, “don’t think, try”. By doing so he introduced the world to the first evidence based vaccine.

“But now listen to the most delightful part of my story. The boy has since been inoculated for the Smallpox which as I ventured to predict produced no effect.” – Letter to friend, dated 19th July 1796, after the successful inoculation of James Phipps

Jenner’s faced a cautious medical establishment, who deliberated at length over his findings before accepting them. It wasn’t until some 17 years after his death, in 1840 that the government banned the use of variolation (the use of smallpox) and under the provisions of the Vaccination Act, provided free vaccinations (using cowpox) to all.

Jenner’s contribution to the world is recognised, if not always correctly. He followed the evidence to its conclusion and the world is a much better place for him!

Edward Jenner, I salute you and your willingness to test on children, including your own son, in the name of science!

More to come – Part Two

I will look into Jenner’s legacy and the efforts of the anti-vaccination movement of the day. I’ll also have a go at the AVN and a few homeopaths, you know, for balance! I’d hoped to have more time to write this all for his ‘death day’, but not to be!

[1] I’ve seen Jenner’s death listed as 3 different dates (23rd, 25th & 26th), but the 26th is by far and away the most quoted.
[2] Unable to find the original source of this quote. This is referenced to Khan 1963, p604.

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