Aristotle and Slavery

I started reading Aristotle's Politics last night. I haven't gotten very far, but what I read was a bit disturbing. Aristotle says that some people are born to be slaves and some people are born to be masters. And of course, he seems to think the class he belongs to is the class of masters. Ok, I have problems with that. I e-mailed my professor, who sent me the piece I was reading, and told him about my trouble. He told me to "think beyond the obvious." He suggested that I look closer at what Aristotle means by slavery, and "natural slaves." Aristotle says, "He who participates in rational principle enough to apprehend, but not to have, such a principle, is a slave by nature." But I am not so sure how you "have" rational principle. So that didn't help so much. He also speaks about the soul and the body, how the soul rules the body, and the body is the slave of the soul, at least it should be by nature. When I try to think "beyond the obvious" idea of slaves, I have to say that most people are a slave to a large number of things, such as our bodies. We have to eat to sustain ourselves; we need money to be able to eat; we have to work to earn the money to be able to eat; we have to get up at a certain time to be able to work to earn the money to be able to eat. In this manner, I think we are all slaves to a certain extent, and it seems that we are slaves to our bodies. When I think beyond our physical needs, most of us also become slaves to the people in our lives, to the other mental and physical demands on us, to our religious beliefs. And all this is not necessarily a bad thing at all - it is, as Aristotle says, natural. I guess the question I have left is, is there any way for a person to NOT be a slave, in any realm at all?