particles that can penetrate into the lungs. >> what happens when a particle goes into the lungs? >> this particular poison works at what we call the cellular level, the most basic level, the cells all over the body are constantly doing things, performing metabolic functions. ricin interferes with that, it breaks down that machinery at a basic level, what happens if someone inhales it, they will have difficulty breathing, some of the earlier symptoms. their lungs will start to fill with fluid in response that poisonous -- the lungs will try to respond, that ultimately is what can cause death. >> if you know what you've inhaled, is it treatable? >> there's no particular anti-dote for ricin, usually we say that people are treated systematically, for example, if you knew someone inhaled it, and they were developing symptoms, you might put them on a breathing machine, try to