Washington - It was the first time in his career fixing hearts at Johns Hopkins Medicine that David Kass had been asked to diagnose a condition like this: A heart two sizes too small suddenly grows three sizes in one day.
For the residents of Whoville, yes, the transformation was wondrous. But when asked to be the Grinch's cardiologist, Kass considered what medical conditions might have caused such a change. Never before had he been asked to diagnose a storybook character - but then again, how many storybook characters have cardiac issues? "Horton has hearing problems," he noted, but you would need an ear, nose and throat specialist for that.
It's almost Christmas. And so researchers at Johns Hopkins, Georgetown University and other learned places are bringing their expertise to some of the holiday's classic tales.
Georgetown professors answered questions such as: Does Santa use big data to find the perfect gift for every child? Why doesn't Claus age?
And they even wondered - Grinch-like - whether there might be some toy-licensing violations going on in Santa's workshop.
At Johns Hopkins, they called on a theoretical particle physicist to explain the ghosts who bring Scrooge into his past and his future in Charles Dickens's "A Christmas Carol."
Moving forward in time is easy, said physicistIbrahima Bah, an assistant professor at Hopkins: Just start moving close to the speed of light.
"In principle, physics allows you to go forward in time compared to another person," he said, drawing on Albert Einstein's theory of special relativity: If one person (say, a ghost) is moving fast compared to someone else, his clock will tick slower; 10 years in the ghost's reference frame could be 30 for the person holding still.
"But we don't know how to move back in time," said Bah, whose name is inescapably Scroogian.
"You would have to have negative energy density. We don't know how to make that, or what that even means." (Indeed.)
If there were a way to tear a hole in the fabric of space - called a naked singularity ring - "if you somehow go through that ring, and come back out, then you would go back in time," he said. "But physically, there is no process that can make a naked singularity ring."
Easier option: Suspend disbelief. Read more Dickens.
Steve Farber, principal investigator at the Carnegie Institution for Science and a Johns Hopkins biology professor, took on another question: Why did Rudolph have a very shiny nose?
He knew there are creatures that light up naturally, such as sea anemones and coral that glow a brilliant red. His team routinely inserts fluorescent jellyfish-like proteins into the zebrafish he works with to make the fish glow to study cardiovascular disease. His theory would take a sort of one-in-a-million chance, but it goes something like this:
Say one of the reindeer is pregnant and feeling lousy while Santa's sleigh is soaring over the Holy Land. She passes out, and despite Santa Claus's desperate efforts to maneuver, the sleigh crashes into the Red Sea. The reindeer gets cut on some coral that has a protein in it that, if you ever saw it, you would even say it glows.
"The question is, how would you get that DNA into Rudolph's DNA?" Farber asked, from the pregnant reindeer's blood to the egg cell that will one day be baby Rudolph.
"There are particles related to viruses called mobile genetic elements that have the ability to cut genomes and insert sequences into the DNA."
But why would just the nose light up? If some DNA from the coral got into a protein that's only in the nose - such as a smell receptor - that could explain it.
Still, while it would be easy to inject the DNA into an egg cell in a lab, it's a little hard to imagine that transfer happening in nature.
Harder than imagining a jolly fat man flying a sleigh around the world in one night? For some, yes.
When Kass, a cardiologist whose research into heart failure has led to discoveries that have helped many people, was asked if the university's public-relations team could videotape him evaluating the Grinch, he said, "I'll do it, but I have to put on a fake Austrian accent and wear my glasses like Chuck Schumer."
He didn't let them slide down his nose, as the Democratic U.S. senator from New York often does, but he was able to come up with a novel explanation. Kass has evaluated many diseased hearts - small and large. If a heart grew as rapidly as the Grinch's, it struck Kass as highly unlikely that the Grinch would be cheerful and active, lifting his sled, handing out presents and whatnot.
Kass drew on research that had interested him, in Science, in which a molecular biologist at the University of Colorado at Boulder studied how a Burmese python's heart grows dramatically after a very large meal, such as a rabbit.
Then, he turned elsewhere in the literature. Just before the rapid expansion of his heart, the Grinch had stolen Who pudding, roast beast and everything down to the very last can of Who hash.
It was obvious: The Grinch must be a snake.
He is very green, but . . .
"He does have legs," Kass acknowledged. "But Dr. Seuss put legs and fur on all sorts of things," including plants. "To me, that's not a defining feature."
And in the end, if his diagnosis ("Snake") is correct, his medical advice would be easy. "Just don't eat so much at once."
More specifically, "Avoid eating something where someone would look at it and not be able to figure out how you ate it all. It's probably generally decent advice, whether you're a snake or not. It may describe a lot of us after Christmas dinner."