this blood a coagulated blood be? and then he ended up being able to do some graphs. he determines that the first initial blood types, it was not a hard experiment, and he did not the dots of tools. that is a moot question. history cannot answer those questions. lives have been saved? i don't know. live said it lost? probably. the third question, what should the relationship of science and society be? should society put limits on science? the third question, if we are looking 350 years later at how initial culture responses were to blood transfusion, something that is complicated but in most circles and problematic. how will history, how will people 50 years, 100 years, 150 years be looking at us as we are trying to come to terms with our stance toward things like human embryo of the stem cell research clowning. these may seem to be very different technologies. in the end those technologies are not all that different and the philosophical realm. each one gets that the question of what it means to be human, what it means to not be human, and in the case of human embryo

. >> is there a coagulant introduced somewhere in the middle of this? . >> this coagulant brings solids together and lets the water run through. that gives us more time in the digestion process, more time to reduce the amount of solids. these are the biggest ones in the world, like we always like to do in san francisco. they are 4 meter, there's none like it in the world. >> really? wow. >> three meters, usually. we got the biggest, if not the best. so here we are. look at that baby hum. river of sludge. >> one of the things is we use bacteria that's common in our own guts to create this reduction. it's like an extra digestion. one of the things we have to do to facilitate that is heat that sludge up and keep it at the temperature our body likes, 98.6 degrees. >> so what we have here is the heat exchanger for digester no. 6. these clog up with debris and we're coming in to -- next wet weather season so we always come through here, clean them out, make sure that we get maximum heat exchange during the colder wet weather. sludge season. >> rubber glove. >

picture, as you're putting this puzzle together, of a disorder called dic, disseminated intravascular coagulationou can bleed from that. when your blood is so thin, when you're so un7ne to make a clot, you can just develop bruises and they can be spontaneous. so just because there were bruises doesn't mean that the child was ever hit. >> thompson: mcclain, who wouldn't give us an interview, said in recent testimony she didn't need the test results because this was such a "clear" case of blunt force injury. she said, "i don't get into ptt. i'm a forensic pathologist and all my people are dead. we don't run ptts." >> you have to put the whole picture together to be able to get to a diagnosis. it's a 500-piece puzzle. and sometimes, that 500-piece puzzle is a snowstorm. >> thompson: the state's experts, in this case, they'll say, "dr. laposata, you got it wrong. when a child or an adult has head trauma, they can get a blood clotting disorder. so, you know, that must be what happened-- that the child was beaten and got this clotting disorder. you got it wrong." what do you say to them? >> if you look