I’m just going to take on the stuff where left off. The hormone I want to talk to you about is called melatonin. And it’s synthesized in the Pineal Gland（松果腺）, which is very small. It is the size of a pea in your brain. Decartes （笛卡尔）called it “the seat of soul”, and it is where melatonin is made. And it has a rhythm as well. And in the sense, it is the opposite of cortisol（皮质醇）. It peaks at night. We call it as the darkness hormone. In every species that we studied, melatonin occurs at night. And it’s a hormone that prepares you for the things, that your species, does at night. So, of course, in humans we sleep, but animals, like rodents（啮齿动物）, they are awake. It’s a hormone that is related to darkness behavior.