Epidemiology: 1773

This evening he disputed the truth of what is said, as to the people of St. Kilda catching cold whenever strangers come. 'How can there (said he) be a physical effect without a physical cause?' He added, laughing, 'the arrival of a ship full of strangers would kill them; for, if one stranger gives them one cold, two strangers must give them two colds; and so in proportion.' I wondered to hear him ridicule this, as he had praised M'Aulay for putting it in his book: saying, that it was manly in him to tell a fact, however strange, if he himself believed it'. He said, the evidence was not adequate to the improbability of the thing; that if a physician, rather disposed to be incredulous, should go to St. Kilda, and report the fact, then he would begin to look about him.

--From Boswell's Life of Johnson--

People who lived in an isolated community noticed they would catch colds when strangers came to visit. Johnson found the idea ridiculous, and later jokes that they must just not like the visitors they were getting.

It's easy to dismiss ideas when they go against a consensus. Fortunately, in science, people make decisions about truth based on falsifiable experiments and not consensus. That's why today we worry about germs instead of our humors.

Echinacea: 1599

Marg. A maid, and stuffed! there's goodly catching of cold.
Beat. O, God help me! God help me! how long have you professed apprehension?
Marg. Even since you left it. Doth not my wit become me rarely?
Beat. It is not seen enough, you should wear it in your cap. By my troth, I am sick.
Marg. Get you some of this distilled Carduus Benedictus, and lay it to your heart: it is the only thing for a qualm.
Hero. There thou prickest her with a thistle.

--From Much Ado About Nothing--

If you take Echinacea because people say it will fight a cold, why not try Carduus Benedictus? Shakespeare recommends it and he's better than "people", isn't he?

Germ warfare: 1790

When those who labour for their daily bread have the misfortune to catch cold, they cannot afford to lose a day or two, in order to keep themselves warm, and take a little medicine; by which means the disorder is often so aggravated as to confine them for a long time, or even to render them ever after unable to sustain hard labour. But even such of the labouring poor as can afford to take care of themselves, are often too hardy to do it; they affect to despise colds, and as long as they can crawl about, scorn to be confined by what they call a common cold. Hence it is, that colds destroy such numbers of mankind. Like an enemy despised, they gather strength from delay, till at length they become invincible.

--From Domestic Medicine--

Now I understand the phrase: "that which does not kill you, only makes you stronger." It's about colds. If you spread them to others and they die you have less competition.

[Note that the author isn't talking about the disease spreading to uninfected people from infected people who refuse to isolate themselves. That idea isn't mentioned in this medical treatise.]

Music to recuperate to: 1748

Bang! Bang! Bang! Wake up! Humors behave!