Scurvy Dogs?

Dogs don't get scurvy. Guinea pigs do. And polar bears are more like lemons than limes are like lemons, on one important margin. 

Reality can be weird.

A fun imagined dialogue, where Forlich is right, but looks completely crazy, because reality can be weird.

Let’s imagine a version of history where the guinea pigs did indeed get lost in the Norwegian mail, so Holst and Frolich only tested dogs, and found no sign of scurvy. Let’s further imagine that Frolich has been struck by inspiration, and through pure intuition has figured out exactly what is going on. 

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Frolich: You know Holst, I think old James Lind was right. I think scurvy really is a disease of deficiency, that there’s something in citrus fruits and cabbages that the human body needs, and that you can’t go too long without. 

Holst: Frolich, what are you talking about? That doesn’t make any sense.

Frolich: No, I think it makes very good sense. People who have scurvy and eat citrus, or potatoes, or many other foods, are always cured.

Holst: Look, we know that can’t be right. George Nares had plenty of lime juice when he led his expedition to the North Pole, but they all got scurvy in a couple weeks. The same thing happened in the Expedition to Franz-Josef Land in 1894. They had high-quality lime juice, everyone took their doses, but everyone got scurvy. It can’t be citrus.

Frolich: Maybe some citrus fruits contain the antiscorbutic [scurvy-curing] property and others don’t. Maybe the British Royal Navy used one kind of lime back when Lind did his research but gave a different kind of lime to Nares and the others on their Arctic expeditions. Or maybe they did something to the lime juice that removed the antiscorbutic property. Maybe they boiled it, or ran it through copper piping or something, and that ruined it.

Holst: Two different kinds of limes? Frolich, you gotta get a hold of yourself. Besides, the polar explorers found that fresh meat also cures scurvy. They would kill a polar bear or some seals, have the meat for dinner, and then they would be fine. You expect me to believe that this antiscorbutic property is found in both polar bear meat AND some kinds of citrus fruits, but not in other kinds of citrus?

Frolich: You have to agree that it’s possible. Why can’t the property be in some foods and not others? 

Holst: It’s possible, but it seems really unlikely. Different varieties of limes are way more similar to one another than they are to polar bear meat. I guess what you describe fits the evidence, but it really sounds like you made it up just to save your favorite theory. 

Frolich: Look, it’s still consistent with what we know. It would also explain why Lind says that citrus cures scurvy, even though it clearly didn’t cure scurvy in the polar expeditions. All you need is different kinds of citrus, or something in the preparation that ruined it — or both! 

Holst: What about our research? We fed those dogs nothing but grain for weeks. They didn’t like it, but they didn’t get scurvy. We know that grain isn’t enough to keep sailors from getting scurvy, so if scurvy is about not getting enough of something in your diet, those dogs should have gotten scurvy too.

Frolich: Maybe only a few kinds of animals need the antiscorbutic property in their food. Maybe humans need it, but dogs don’t. I bet if those guinea pigs hadn’t gotten lost in the mail, and we had run our study on guinea pigs instead of dogs, the guinea pigs would have developed scurvy.

Holst: Let me get this straight, you think there’s this magical ingredient, totally essential to human life, but other animals don’t need it at all? That we would have seen something entirely different if we had used guinea pigs or rats or squirrels or bats or beavers?

Frolich: Yeah basically. I bet most animals don’t need this “ingredient”, but humans do, and maybe a few others. So we won’t see scurvy in our studies unless we happen to choose the right animal, and we just picked the wrong animal when we decided to study dogs. If we had gotten those guinea pigs, things would have turned out different.