Similia Similibus Curantur

This is part 2 of a series. You can read part 1 here.

One of the greatest European scientists of the late medieval period was Paracelsus (known as Philippus Aureolus Theophrastus Bombastus von Hohenheim to his friends), the founder of toxicology.

Big Daddy P rocking a double red hat

And it was his detailed, scientific approach to understanding human health four centuries ago that paved the way for vaccinations, although he himself never successfully developed one.

One of his most revolutionary and important acts was publicly burning the “medical” texts written by the quack Roman doctor Galen in the central square of Basel, Switzerland, marking Paracelsus as one of the first medical experts to defy the centuries-long superstitious belief in the “four humors” that we covered in part 1 of this series.

Hair of the Dog

Like all scientists in his day, Paracelsus published all of his research in Latin, and it’s from him that we get the term similia similibus curantur, usually translated into English as “like cures like.”

If you’ve ever uttered the expression “hair of the dog,” this is an expression of the medieval belief (predicated upon Galen’s teachings and others) that a small dose of something will cure a larger, more dangerous dose.

Today, “hair of the dog” usually means drinking a small volume of alcohol the day after you’ve intoxicated yourself by drinking a large volume of alcohol.

Originally, however, the expression “hair of the dog” referred to the belief that a wound from a dog bite could be healed by placing one of the offending dog’s hairs into the wound.


Paracelsus dedicated much of his life to finding cures for infectious diseases like syphilis, and although he never quite discovered any enduring solutions, he was able to prove that a lot of the so-called treatments en vogue at the time were utter horseshit.

Today, his theory of “like cures like” isn’t generally thought to be part of modern medicine.  It’s only “fringe” medical practices such as homeopathy that still adhere to that philosophy.

But in one particular circumstance, it turns out that Paracelsus was genuinely onto something when it came to treating illnesses.

Today, we call it “vaccination” or “inoculation.”

And the theoretical underpinnings of vaccine theory and the theory of hermeneutics (of which Paracelsus was a staunch advocate) play a very, very big role in how we got to World War 3, as we shall see anon.

A Pox Upon Your Science

You know, it’s more than a little telling that the only infectious disease (smallpox) that doctors have ever eradicated in the history of medicine happened more than 200 years ago.


Despite all the hype and the talk and the promises and the soaring stock prices, modern medicine has never managed to wipe out even a single infectious disease.


If you ask an epidemiologist or “public health expert,” they’ll tell you that Dr. Edward Jenner is the “father of immunology” for discovering a systematic way to apply the “like cures like” philosophy to treating diseases, the process we now call “vaccination.”

The textbooks will gush excitedly about Jenner’s accomplishments, but I don’t find them particularly praiseworthy.

To understand what Jenner did, it’s important to know that (human) smallpox is just one of a number of “poxes,” all cousins in a large family of viruses.

In fact, poxes are so common that nearly every kind of mammal has its own “pox.” And all the poxes are very closely related, genetically speaking, to one another.

As such, throughout history, human beings were sometimes infected by mammalian poxes, especially cowpox (today, we call this “zoönotic” transmission).

To put it into modern terms, medieval European milkmaids had a cowpox “infection rate” of more than 90%. Getting some skin rashes or coming down with a minor fever from being around cows all the time was just considered part of the job and no big deal.

Furthermore, plenty of people throughout history (starting with the Chinese) had noted that people who had previously been infected by an animal pox were immune against the much deadlier human version (smallpox).

Jenner’s only real accomplishment was to scientifically test this “old maid’s tale” about acquired immunity to see whether it was true.  And when it came to smallpox, it was.

Jenner then wrote up his notes and published them in the journal of the (British) Royal Society, achieving worldwide fame.  Since his vaccine theory confirmed traditional European beliefs about “like causing like,” it made sense to people.

And because his original vaccination process involved taking pus from infected (female) cows (“vacca” in Latin) and injecting it into people, Jenner’s method ultimately became known as vaccination.

Therefore, to “vaccinate” someone literally means to “cow-ify” them.

Fun, eh?

Unethical to an Extreme

While Jenner is widely lauded for “inventing” vaccines, what is far less well known is the fact that he was an extremely wealthy and privileged white man living in imperial Britain who first tested his vaccination theory on an 8-year-old child, the son of one of Jenner’s bonded servants, completely against the kid’s will.

Paging Dr. Mengele to the white courtesy phone

Jenner scraped some pus from an infected cow and then injected it into the child.  The poor boy then got a high fever and nearly died.

After the kid recovered, Jenner then injected him with some full-strength smallpox.

Incredibly unethical.

But not unusual. For some reason, nearly all of the inventors of vaccines were flaming assholes.

Nonetheless, Jenner’s experiment worked. The kid who had been forcibly injected with cowpox had indeed developed immunity to smallpox.

Despite this, it still took one hundred and eighty years to eradicate smallpox via vaccination.

A Deadly Legacy

Unfortunately, Jenner’s success with the smallpox vaccine has led to a lot of spectacular failures in medicine.

My best estimate is that a few million people, at least, have died or become seriously ill over the past 200 years because of failed attempts to create other vaccines as successful as the smallpox vaccine, including one particular malaria vaccine trial that killed twice as many people as the disease itself.

Various vaccines have been developed over the years to try and cure diseases like cholera, Ebola, swine flu, and polio, but they’ve never ever come close to the success of the smallpox vaccine.

Yet the mania for vaccines has only increased over time, despite these colossal setbacks. Right now, half of my news feed is composed of articles debating, discussing, and eagerly anticipating the arrival of new vaccines.

Nonetheless, we must remember that vaccines have only ever eradicated one disease, and that vaccine was developed two centuries ago.

Why Did Vaccinations Eradicate Smallpox But Not Other Viruses?

Well, there are several reasons, but the most important one lies in the name of vaccinations themselves – cows.

Family farms as we all picture them in our head do not really exist anymore, but they are epitomized in the classic English folk song Old MacDonald Had a Farm.

Most versions of the song list the animals (and the noises they make) found on the eponymous farmer’s farm:

  • a cow
  • a dog
  • a pig
  • a duck
  • a hen/chicken
  • a goat
  • a donkey

All of those animals would’ve been common on any farm worldwide, whether it be in Asia, Africa, the Middle East, or Europe, with one exception: the cow.

I don’t want to get too sidetracked by a lengthy aside into how cows were domesticated, but the short version is that cows were the last animal on Old MacDonald’s farm to live in large numbers in close proximity to people.

And many places around the world never domesticated cows, particularly Southeast Asia, the Pacific, and the Americas, to wit, many populations are still classified as lactose intolerant because of a lack of historical exposure to dairy cows.

Herd Immunity

Poxes, in general, are believed to have originated in rats or mice, but only a handful of animal poxes are known to be able to “cross over” and infect humans, primarily monkeypox and cowpox (chickenpox, despite its name, does NOT come from chickens and is not a disease that chickens ever get).

Since people have never “domesticated” monkeys or worked with large herds of them, it’s only the cowpox that regularly crossed over to humans (horsepox, for unknown reasons, almost never infects people).

And it was the human populations that had dairy cows (Central and South Asia, Africa, Europe, and the Middle East) that slowly began developing natural immunity to smallpox.

That might sound wildly incorrect considering that smallpox was a major killer in Europe in the 18th century when Dr. Jenner was operating, but nonetheless, it is estimated that only around 30% of people in cow herding societies died after being infected with smallpox.

A 30% infection rate is very, very high, of course, but when you compare that to completely unexposed populations like those in the Americas, the death rate there was the mirror opposite – at least 70% (and possibly a much higher percentage) of indigenous Americans and Pacific Islanders died after becoming exposed to smallpox.

Simply put, a lot of cow herding Europeans, Central and South Asians, Africans, and Middle Easterners had been exposed to poxes over the centuries, and their descendants were far more naturally resilient to smallpox than other populations who were never regularly exposed to animal poxes.

Little Brother and Big Brother

In addition, even the human smallpox virus comes in two variants – one called “major” and one called “minor,” for obvious reasons.

Historically, the “minor” version never killed more than 1% of the people it infected.

Indeed, getting the “minor” version of smallpox was almost identical to getting the flu today: a fever, possibly a headache, a feeling of weakness, and muscle pain.  Rest in bed for a few days, drink plenty of fluids, and you’ll be fine.

It was only the “major” version of smallpox that was likely to kill you, although again, the overwhelming majority of people from cow herding societies survived it.

Lucky Strike

Jenner’s original method of “vaccination” of exposing people to cowpox in order to inoculate them against smallpox worked most of the time.  But exposing people to the minor version of smallpox did an even better job of inoculating them against the major version.

Indeed, the smallpox vaccine by the World Health Organization (about which we will say much more later on) to eventually eradicate the disease was based on the minor version of smallpox.

Unfortunately, no other deadly viruses today have a “weak brother” from which to confer natural immunity or develop a vaccine.

More or less, humanity got very lucky that smallpox naturally had a number of weak “brothers” that were critical to developing human immune system resilience against the stronger “big brother.”

That is the main reason why modern scientists have never ever been able to duplicate “Jenner’s” success with vaccines and why they probably never will be.

Click here to read part 3.

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