So, you see, physical illness can have psychological causes. Now, we just have time to introduce another interesting example of the interaction between the mind and the body - placebos. Placebos, maybe you've heard them called sugar pills, are harmless substances - not always sugar - that are used routinely on groups of sick people in experiments. These experiments test the effectiveness of new drugs. One group is given the new drug, the other group is given a placebo, and the results are measured. As you might guess, some of the people who receive the new drug get better. Surprisingly, however, some of the placebo group also get better. Why? Well, it's an interesting question, one which doctors can't quite answer. Some of the group may have gotten better on their own, without any treatment at all. But research has shown that the very act of taking a medication that you think will make you better, often does make you feel better. Have you ever taken an aspirin and felt better in five minutes? Aspirin doesn't work that fast, does it? Basically, if you believe you will get better, sometimes you do. The history of how doctors and healers have used the mind-body connection to cure people is long and interesting. But I see that it's time to close, so I'll have to cover this in the next class. You have to hold your questions on this topic till then. Before you go, I have some handouts for you concerning the midterm exams next week.