 Like, you know, a human body doesn't recognize it at all, but you don't want it human-y to the point where anybody's going to get sick. And that's the real fear in making a vaccine is that people will get the disease, you know? I see. Oh, so you just put your finger on it. So he's looking for a... He's trying to mute or attenuate it so that it's right at that perfect fault line between...