How Many Germs Are in a Kiss?


Your mouth is home to 700 different kinds of bacteria, and you may have wondered just how many germs you’re getting—or giving!—when you swap spit with someone else. A new study, just published in the journal Microbiome, provides the answer (germaphobes, you might want to look away now): In a 10 second kiss, an average of 80 million bacteria are transferred.

Researchers from the Amsterdam-based Micropia Museum and TNO Microbiology and Systems Biology in the Netherlands focused on intimate kissing, “involving full tongue contact and saliva exchange … unique to humankind and common in over 90 percent of known cultures.” The scientists asked 21 couples, aged 17 to 45, who visited the Artis Royal Zoo in Amsterdam to fill out questionnaires—which included queries on the last time they ate, time passed since their last kiss, and how often they engaged in intimate kissing—then had them spit into a tube and swabbed tongues with cotton to analyze what bacteria were already on their tongues and in their saliva. They found that couples had similar bacteria in their saliva and on their tongues, possibly due to shared habits (like smoking), diets, and even toothpaste.

To figure out just how many bacteria make the jump during a kiss, they asked one person from each couple to drink a probiotic liquid that contained specific varieties of Lactobacillus and Bifidobacteria which, according to the researchers, make up 0.15 percent of the bacteria in saliva and 0.01 percent of the bacteria on the tongue on average. After the couple made out, they repeated the spit-and-swab routine; when the researchers analyzed the samples, they found that the quantity of the probiotic bacteria was .54 percent in the receiver’s saliva and .49 percent on the tongue. (Additionally, Remco Kort, lead researcher and microbiologist at the Netherlands Organisation for Applied Scientific Research in Amsterdam, told CBS that “significant difference in height between French-kissing partners can result in a greater exchange of saliva—downward—to the shorter participant.”)

The researchers also found that couples who shared at least nine intimate kisses a day were also more likely to have similar microbes in their saliva—but that they weren’t likely to stick around in the absence of French kissing. “Our findings suggest that the shared microbiota among partners is able to proliferate in the oral cavity,” they write in the study, “but the collective bacteria in the saliva are only transiently present and eventually washed out, while those on the tongue’s surface found a true niche, allowing long-term colonization.”

A steamy tongue kiss might transfer 80 million bacteria, but according to a “Kiss-O-Meter” installed at the Micropia Museum, only 1000 bacteria are transferred by a quick smooch. Pucker up!

What Are the 12 Days of Christmas?

Everyone knows to expect a partridge in a pear tree from your true love on the first day of Christmas ... But when is the first day of Christmas?

You'd think that the 12 days of Christmas would lead up to the big day—that's how countdowns work, as any year-end list would illustrate—but in Western Christianity, "Christmas" actually begins on December 25th and ends on January 5th. According to liturgy, the 12 days signify the time in between the birth of Christ and the night before Epiphany, which is the day the Magi visited bearing gifts. This is also called "Twelfth Night." (Epiphany is marked in most Western Christian traditions as happening on January 6th, and in some countries, the 12 days begin on December 26th.)

As for the ubiquitous song, it is said to be French in origin and was first printed in England in 1780. Rumors spread that it was a coded guide for Catholics who had to study their faith in secret in 16th-century England when Catholicism was against the law. According to the Christian Resource Institute, the legend is that "The 'true love' mentioned in the song is not an earthly suitor, but refers to God Himself. The 'me' who receives the presents refers to every baptized person who is part of the Christian Faith. Each of the 'days' represents some aspect of the Christian Faith that was important for children to learn."

In debunking that story, Snopes excerpted a 1998 email that lists what each object in the song supposedly symbolizes:

2 Turtle Doves = the Old and New Testaments
3 French Hens = Faith, Hope and Charity, the Theological Virtues
4 Calling Birds = the Four Gospels and/or the Four Evangelists
5 Golden Rings = the first Five Books of the Old Testament, the "Pentateuch", which gives the history of man's fall from grace.
6 Geese A-laying = the six days of creation
7 Swans A-swimming = the seven gifts of the Holy Spirit, the seven sacraments
8 Maids A-milking = the eight beatitudes
9 Ladies Dancing = the nine Fruits of the Holy Spirit
10 Lords A-leaping = the ten commandments
11 Pipers Piping = the eleven faithful apostles
12 Drummers Drumming = the twelve points of doctrine in the Apostle's Creed

There is pretty much no historical evidence pointing to the song's secret history, although the arguments for the legend are compelling. In all likelihood, the song's "code" was invented retroactively.

Hidden meaning or not, one thing is definitely certain: You have "The Twelve Days of Christmas" stuck in your head right now.

Big Questions
Where Does the Phrase '… And the Horse You Rode In On' Come From?

Horses may no longer be the dominant form of transportation in the U.S., but the legacy of our horseback-riding history lives on in language. When telling people off, we still use the phrase “... and the horse you rode in on.” These days, it’s rare for anyone you're telling to go screw themselves to actually be an equestrian, so where did “and the horse you rode in on” come from, anyway?

Well, let’s start with the basics. The phrase is, essentially, an intensifier, one typically appended to the phrase “F*** you.” As the public radio show "A Way With Words" puts it, it’s usually aimed at “someone who’s full of himself and unwelcome to boot.” As co-host and lexicographer Grant Barrett explains, “instead of just insulting you, they want to insult your whole circumstance.”

The phrase can be traced back to at least the 1950s, but it may be even older than that, since, as Barrett notes, plenty of crude language didn’t make it into print in the early 20th century. He suggests that it could have been in wide use even prior to World War II.

In 1998, William Safire of The New York Times tracked down several novels that employed the term, including The Friends of Eddie Coyle (1972) and No Bugles, No Drums (1976). The literary editor of the latter book, Michael Seidman, told Safire that he heard the term growing up in the Bronx just after the Korean War, leading the journalist to peg the origin of the phrase to at least the late 1950s.

The phrase has had some pretty die-hard fans over the years, too. Donald Regan, who was Secretary of the Treasury under Ronald Reagan from 1981 through 1984, worked it into his official Treasury Department portrait. You can see a title along the spine of a book in the background of the painting. It reads: “And the Horse You Rode In On,” apparently one of Regan’s favorite sayings. (The book in the painting didn't refer to a real book, but there have since been a few published that bear similar names, like Clinton strategist James Carville’s book …and the Horse He Rode In On: The People V. Kenneth Starr and Dakota McFadzean’s 2013 book of comics Other Stories And the Horse You Rode In On.)

It seems that even in a world where almost no one rides in on a horse, insulting a man’s steed is a timeless burn.

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