A sobering reminder of the limits of science in the war on vampiresS

Although science can achieve great things, it can only do so after a lot of thought and effort. Nowhere do we see that more clearly than in the strange tales of two real-life scientific institutions' brave attempts to guard the population from vampire attacks.

In 1994, a Norwegian group of scientists were so concerned with the threat of vampirism that they needed to study some effective way to fight against it. They decided to check on the old superstition that garlic repelled vampires. Because they had few vampires on hand, they volunteered leeches. Leeches were put on people's hands. Some of those hands were smeared with garlic, and some were plain.

To their dismay, they found that leeches preferred the garlic smeared hand in two out of three cases. When they preferred the garlic hand, they latched on in one third the time it took them to get interested in the plain hand. If anything, then, we weren't fighting vampires so much as seasoning ourselves for them.

Clearly, the 1994 group was prescient in their prediction of a vampire invasion, but their experimental data doesn't hold up. Another group of researchers measured how leeches reacted to several different foods - specifically garlic, beer, and sour cream. (I'm guessing these were the foods they had in their fridge at the time the urge to experiment struck them.) They found that beer made the leeches discombobulated, sour cream made them love the containers they were in, but didn't affect their taste for human blood, and garlic killed them. Just outright killed, fast and horribly. When put on arms that had been smeared with garlic, the leeches wriggled, making no attempts to eat at all. They were taken off the arms and put in water, and even offered garlic-free arms in a desperate attempt to save their lives, but they died in about three hours. After two leeches had the same reaction, the experiments were discontinued "for ethical reasons." We may fight monsters, but we don't have to sink to their level.

This puts us lay people in a quandary. We have two experiments that are very similar. One resulted in full, happy leeches. The other resulted in dead leeches. How did the disparity in results occur? This is something that often happens in science. Two experiments are conducted, and they have exactly opposite results. How is it even possible for that to happen?

Sometimes, it's simply by chance. If the results are weak - a mild positive response in one case and a mild negative one in the other - the experiment is testing an unrelated factor and by chance, the results vary one way in one experiment and the other way in the next. That doesn't seem to be the case in the leech experiments. It's possible that the solution to our dilemma is in some overlooked variable. Was there a different in garlic concentration? Garlic type? Leech type? Were the leeches kept in different conditions or did the blood volunteer (in either case) have some peculiar biochemistry? It's possible.

But maybe it's something more. Maybe it's vampire propaganda. And if this were about a war on vampires, who should we believe? Was the 1994 team setting the stage for a vampire invasion, making people believe that effective weapons don't work? Or is the new team throwing doubt on time-tested evidence, as a sort of vampire underground movement? Only time, and more studies, will decide.

Who wants to volunteer to have their garlic-laden blood drawn?

Via NCBI, Universitetet i Bergen.