Words to the wise: Muscling in
Authors: G. Hutchison
Journal: BMJ (1998)

In response to Jeff Aronson’s filler about fillers (a meta-filler?), and the subsequent editorial plea for further alternatives to the word “filler,” I would like to suggest intercalation. The word has a medical pedigree in the form of intercalated discs (which is what we called the striations in skeletal muscle fibres when I was a medical student), and it also fits the bill descriptively: the Oxford English Dictionary defines it as “the insertion or interjection of something additional or foreign.”

It arrived at its current meaning after a long journey from an Indo-European root that was pronounced kal or gol, and which meant something like “to announce.” From this ancient origin, the word spread out across Europe. Northern European tongues preserve the sound and meaning in various words, including the English call. Slavic languages have a root glagol, meaning “word,” which gives us Glagolitic, the name of an old alphabet that has been largely replaced by Cyrillic—it looks as if it might have been rather too curly to write quickly. (The Cyrillic alphabet, incidentally, is named for Saint Cyril, a ninth century Greek missionary, who patched it together from Greek and Hebrew letters in order to produce a writing system for the Slavic languages. Saint Methodius was also involved, but he seems to have been the loser in the struggle for posterity.)

In Latin, the same Indo-European root gave rise to the word calare, to proclaim. The first day of each Roman month was a day for priestly proclamation; these days were therefore referred to as the Calends. From that, we derive our word calendar.

Now, the Roman year of 12 lunar months added up to a total of only 355 days. It moved inconveniently out of synchrony with the seasons unless extra days or months were inserted at intervals; a total of seven extra months every 19 years were required. So on the Calends, the priests would announce any forthcoming intercalary additions to the normal year. And it is the notion of “something extra inserted” that comes down to us in intercalation.

In Republican Rome, intercalation was a political tool: priests could prolong the term of office of a favoured magistrate, or delay the accession of an enemy. Adjustments therefore had little to do with calendrical accuracy, and by 47 bc winter was arriving in March. Julius Caesar legislated 90 extra days in 46 bc to get things back in step with the seasons, and then abolished the lunar calendar that had caused all the problems. He increased the length of the year by adding fixed days to various months, and introduced the leap year to bring the average year length up to 365.25 days. The result was the Julian calendar, and the month of July still bears his name.

But the Julian year is just a little too long—by rather less than a day a century. So in 1582 Pope Gregory XIII was obliged to abolish 10 days in October in order get the date of Easter back in line with the seasons. To prevent such an inconvenience recurring, he introduced a final calendrical subtlety that we will soon have the chance to celebrate. He trimmed three leap years out of each four centuries: 1600 was a leap year, but 1700, 1800, and 1900 were not. We are now due another leap century, and on 29 February 2000 I plan to raise a glass in toast to the continuing complexities of intercalation.