 Could you just walk us through what exactly Hilleman's doing in this trial process? Sure. So he starts with adults, and then you work your way down to children. And what he's doing is he's injecting his vaccine and just being like, do you die or are you okay? Yeah, well, yeah, not quite that grim, but yeah. Or is it safe, and is it inducing an immune response which is likely to be protective? Okay. So you give them the vaccine, you check back in, you draw their blood, and then you look for antibodies. Right.