In order to really study the social history of the Middle Ages, you have to understand the role of spices. Now, this might sound a little spurring, even a little strange. But what seem like little things now were back then actually rather big things. So first let’s define what a spice is. Technically speaking, a spice is part of an aromatic plant that is not a leaf or herb. Spices can come from tree bark like cinnamon, plant roots like ginger, flower buds like cloves. And in the Middle Ages. Europeans were familiar with lots of different spices, most important being pepper, cloves, ginger, cinnamon, maize and nutmeg. These spices literarily dominated the way Europeans lived for centuries, how they traded and even how they used their imaginations. So why this medieval fascination with spices? We can boil it down to there general ideas briefly. One was cost and rarity. Uh two was exotic taste and fragrance. And third, mysterious origins and kinds of mythical status. Now for cost and rarity, spices aren’t native to Europe and they had to be imported. Spices only grew in the East Indies and of course transportation costs were incredibly valuable even from the very beginning. Here is an example. In 408 AD, the Gothic General who captured Rome demanded payment. He wanted 5000 pounds of gold among other things but he also wanted 3000 pounds of pepper. Maybe that would give you an idea of exactly where pepper stood at the time. By the Middle Ages, spices were regarded as so important and expensive they were used in diplomacy, as gifts by heads of state and ambassadors. Now for the taste. The diet then was relatively bland, compared to today’s. There wasn’t much variety. Especially the aristocracy who tended to eat a lot of meat, they were always looking for new ways to prepare it, new sources, new tastes and this is where spices came in. Now, this is a good point to mention one of the biggest myths about spices. It’s commonly said that medieval Europeans wanted spices to cover up the taste of spoiled meat. But this isn’t really true. Anyone who had to worry about spoiled meat couldn’t afford spices in the first place. If you could afford spices, you could definitely afford fresh meat. We also have evidence that various medieval markets employed a kind of police to make sure that people did not sell spoiled food, and if you were caught doing it, you were subject to various fines, humiliating public punishments. So what actually was true was this：In order to have meat for the winter, people would preserve it in salt, not a spice. Spices actually aren’t very effective as preservatives. And throughout winter, they would eat salted meat, but the taste of the stuff could grow really boring and depressing after a while. So the cook started looking for new ways to improve the taste and spices were the answer, which brings us to mysterious origins and mythical status. Now the ancient Romans had a thriving spice trade and they sent their ships to the east and back. But when Rome collapsed in the fifth century and the Middle Ages began, direct trade stopped, and so did that kind of hands-on knowledge of travel and geography. Spices now came by way of the trade routes with lots of intermediaries between the producer and the consumer. So these spices took on an air of mystery. Their origins were shrouded in exotic travels. They had the allure of the unknown, of wild places. Myths grew up of fantasy lands, magical faraway places made entirely of food and spices. And to that, spices themselves had always been considered special or magical not just for eating and this was already true in the ancient world where legends about spices were abundant. Spices inspired the medieval imagination. They were used as medicines to ward off diseases, and mixed into perfumes, incent. They were used in religious rituals for thousands of years. They took on a life of their own and they inspired the medieval imagination, spurred on the age of discovery in the 145th and 16th centuries. When famous explorers like Columbus and da Gama and Magellan left Europe in their ships, they weren’t looking for a new world.; they were looking for spices. And we know what important historical repercussions some of those voyages had.
TPO 18 Lecture 4 Biology
A：Well, it’s finally looking like spring is arriving. The last of the winter snow would be melting away in a few days. So before we close today, I thought I’d mention a biological event that’s a part of the transition from winter to spring, something you can go outside and watch if you have some patience. There is a small creature that lives in this area; you’ve probably seen it. It’s the North American wood frog. Now the wood frog’s not that easy tosspot since it stays pretty to close to the ground, under leaves and things and it blends in really well with its background as you can see. But they are worth the effort because they do something very unusual, something you might not have even thought possible. OK North American wood frogs live over a very broad territory or range. They’re found all over the northeastern United States and all through Canada and Alaska, even inside the Arctic Circle. No other frog is able to live that far and north. But wherever they live, once the weather starts to turn cold and the temperature starts to drop below freezing, as soon as the frog even touches an ice crystal or a bit of frozen ground, well, it begins to freeze. Yeah...yes to me. You look a little bit taken aback.
B：Wait, you mean it’s still alive but it freezes, solid?
A：Well, almost. Ice forms in all the spaces outside the cells but never within a cell.
B：But… then how does its heart beat?
A：It doesn’t.
B：But…then how could it…….
A：You are gonna do such a thing? Well, that first touch of ice apparently triggers a biological response inside the frog. That first of all starts drawing water away from the center of its body, so the middle part of the frog, its internal organs, its heart, lungs, liver, these start getting drier and drier while the water that’s being pulled away is forming a puddle around the organs just underneath the skin. And then that puddle of water starts to freeze. OK, up to known, the frog’s heart is still beating, right? Slower and slower but…and in those last few hours before it freezes, it distributes glucose, a blood sugar throughout its body, its circulatory system, sort of acts like an an antifreeze.
B：A solution of antifreeze like you put in your car in the winter?
A：Well, you tell me. In frogs, the extra glucose makes it harder for the winter inside the cells to freeze. So the cells stay just slightly wet, enough so that they can survive the winter. Then after that, the heart stops beating altogether. So is that the same?
B：I don’t really know, but how long dose it stay that way?
A：Well, it could be days or months, all winter in fact but umm, see the heart really doesn’t need to do any pumping now because the blood is frozen too.
B：I just, I guess I just don’t see how it isn’t, you know, clinically dead.
A：Well, that’s the amazing thing and how it revives is pretty amazing too. After months without a heartbeat, spring time came around again, the earth starts to warm up and suddenly one day, ping, a pulse, followed by another one, then another until maybe ten, twelve hours later, the animal is fully recovered.
B：And does the thawing process have some kind of trigger as well?
A：Well, we are not sure actually, the clearer thing is even though the sun is warning the frog up on the outside, its inside thaw out first, the heart and brain and everything. But somehow it all just happens that way every spring.
B：But after they thaw does it affect them like their lifespan?
A：Well, hmm, we really don’t know a lot about how long a wood frog normally lives, probably just a few years but there is no evidence its longevity. It does have some other impacts though. In studies, we found that when it comes to reproduction, freezing diminishes the mating performance of males. After they’ve been frozen and thawed of course, they don’t seem quite as vocal. They move slower and they seem to have a harder time recognizing a potential mate. So if the male frog could manage not to go through this freezing cycle, he’d probably have more success in mating.
