The butler didn't do it…it was locums!
There I was, innocently reading the Dover Thrift Edition of "Victorian Tales of Terror," when suddenly, like a phantom in the night, contingent labor cast its shadow over me as I turned a page and read...
"Bring one of your best men, and come with me to the haunted mill. But first let me exact from you a pledge of honor that, if our journey should result in nothing, you will keep the matter secret, as I am very sensitive to ridicule."
"He looked at me in amazement, and then, as he burst into a hearty laugh, exclaimed: 'I say, my friend you are over-working yourself. It's time you got a locum tenens, and took a holiday.'"
The story in which that was written, "The Corpse Light," was originally published in 1899. I was reminded how long the concept of contingent labor has been around. But the earliest reference to it that I can find to contingent usage is still this one, from 1347.