William Saletan's thoughts on research into artificial blood cells:
The idea of having little plastic sacks pumped into your bloodstream sounds pretty freaky. We're talking about filling you with petroleum products in a way that challenges the meaning of "flesh and blood." For all I know, further animal or human testing may find unforeseen health risks from this kind of mixture, particularly at such a small scale and with such pervasion of the body. But if the technology turns out to be safe, it'll go a long way toward loosening our concept of ourselves as biological creatures.