The basic story here is that Dr Lazarus (an old man) invents a machine which restores his youth, thus offering the promise of eternal life. The Doctor turns up, and is unimpressed by this plan. Then there's a bunch of pseudo-science where Lazarus turns into a shape-shifting monster that has to suck the "life force" out of people, leaving them as dessicated husks.
The obvious allusion here is to the story of Lazarus in the New Testament: he was a man who died, and then Jesus performed a miracle by bringing him back to life. (There's an explicit acknowledgment of this later in the episode, where the Doctor says that it "seems appropriate" for Lazarus to still be alive after he appeared to be dead.) Personally, I thought this was a bit clumsy, but I suppose that if I can accept Otto Octavius becoming Dr Octopus then I ought to be forgiving here too; maybe it was the constant jokes that got him interested in the subject in the first place.
As for the main concept, the Doctor claimed that this was against the laws of Nature, but I don't see it that way. I'm not an expert in this field, but here's my basic understanding: Every cell in our body contains a complete set of our DNA, with all the instructions for building you. These cells are continuously being replaced, so they make copies of themselves. If you think about photocopying a page in a magazine, and then making a photocopy of that copy, and then a photocopy of the second copy, and so on, you'll eventually wind up with a pretty blurry print-out, due to cumulative errors. In a similar way, the copies of our DNA in our cells gradually get degraded, and this accounts for things like grey hair and wrinkles.
Continuing the analogy, if you make a digital copy of a computer file then the copy is exactly the same as the original. You can keep making copies of copies of copies, and 1000 "generations" later you'd still have something which is identical to your original file. So, I think that ageing is due to a flaw in the copying process, and there's nothing intrinsically wrong with correcting that flaw. Rather than messing around with sonic waves, I think the way to do it would be to make a sample of your DNA while you're young, and store it. Then when you get older, you'd need to re-introduce the "perfect" copy, and get that to replicate itself like a virus. I'm not quite sure how you'd achieve this, but the theory seems plausible to me.
The main problem I'd see with this approach is overpopulation: if people stay eternally young, and keep having children, you'll wind up with too many people and not enough resources to sustain them. Mind you, this process wouldn't eliminate death altogether: you could still be run over by a car or die of cancer. Also, it would depend on whether it's available to everyone, or just a select few, so if Lazarus just kept the technology for himself then there wouldn't be any major demographic shifts. For that matter, given that there's no UK legislation for maximum number of children per household, it would be a bit unfair to single out this one method as being wrong. Anyway, this does raise interesting questions, which have been dealt with in various ways in other SF stories; for instance, there was a short Future Shocks comic (written by Alan Moore) where nobody is allowed to have children anymore, so couples rent kiddie robots at Christmas. Another approach would be to start colonising other planets, which would at least delay the long term problem. However, this episode didn't even mention this issue at all.
Aside from the knee-jerk reaction that the experiment was unnatural, the Doctor also argued that immortality could be a curse rather than a gift. This seemed a bit hypocritical to me, given that he's had plenty of additional lifetimes (with several more to come), but I suppose there's an argument for saying that he can speak from experience. The Highlander TV series also addressed this issue, by showing the different ways that immortals have handled their long lives. Paraphrasing from memory, one conversation went like this:
Lazarus: "I've got so much more to accomplish, think what I can do with the extra time."
Doctor: "It doesn't work like that - some people achieve more in 20 years than others do in 80."
Lazarus: "Yes, but think about what the right person can do!"
Again, I'd have to side with Lazarus on this one. I'm willing to accept the Doctor's premise that some people are amazingly productive, while others waste their lives in futile pursuits (arguably including blogging!), and I've heard the theory that "the candle that burns twice as bright burns half as long". However, if Einstein had been able to live 50 years longer, maybe he'd have figured out his grand unified theory; I'm sure there are several other great minds you could say similar things about. One problem with humans is that we can spend our lives becoming experts in a particular field, then we die, and someone else has to start all over again by learning the basics. There's a novel by Marvin Minsky and Harry Harrison where they claim that a machine intelligence is essentially immortal (given that you can replace any defective parts), and I can see definite benefits to that.
Ultimately, the moral issues were side-stepped in favour of vampire logic: if Lazarus can only sustain his youth by killing other people then that's not fair, because he's preventing them from achieving things in their future.
At the end of the episode, Lazarus was killed, after Martha and her sister lured him (in monster form) into the bell-tower and the Doctor played loud organ music. This struck me as slightly odd. The original experiment involved the use of sonic waves, so I can accept the premise that a loud noise could make the monster vulnerable. (There's an old Spider-Man story where he does something similar, aided by church bells.) However, why go up to the bell tower if you're not going to use the bells? I don't know a great deal about Southwark Cathedral, but I'd expect the organ to be louder in the main part of the church, since that's where the people are sitting, and there aren't any walls/ceilings in the way. Also, unless I missed something, the sound didn't have any "weird science" effect on the monster, it just knocked him off balance so that he fell down to ground level. I'm aware that the inner ear controls balance, and I once (accidentally) sounded a small bell while I was on a church roof, which was loud enough to leave me vibrating for a couple of seconds. However, if the noise was loud enough to knock the monster off balance, and loud enough for Tish (the sister) to cover her ears, how come it didn't affect Martha (who was dangling from a walkway at the time)? Her hearing didn't even seem to be affected afterwards.
Moving on to other aspects of the episode, at one point the Doctor was running away from the monster with Martha and Tish. All three of them were running downstairs, and the Doctor took the lead, which seemed rather unchivalrous of him! Given that he was the fastest runner, I'd expect him to bring up the rear, so that he could fight the monster off with his sonic screwdriver if necessary. This would make some sense if he wanted to run on ahead to warn the rest of the guests, but he didn't try warning them until the two women had caught up with him, and nobody listened to him anyway (until the monster appeared).
During the ensuing stampede, Martha's brother (Leo) was hit in the head by a flying tray. She gave him a quick check, by tilting his head back and looking at his eyes, then announced that he had a concussion. Quoting from the first aid manual:
Concussion produces widespread but temporary disturbance of normal brain activity. However, it is not normally associated with any lasting damage to the brain. The casualty will suffer impaired consciousness, but this only lasts for a short time (usually only a few minutes) and is followed by a full recovery. By definition, concussion can only be confidently diagnosed once the casualty has completely recoved.
So, there might be situations where you suspect that someone has a concussion, in which case you should keep them under observation to see what happens; bearing that in mind, I think that Martha's mother had a point when she complained about her abandoning them outside the building (when she went back inside). It's not as if Martha was particularly helpful to the Doctor: she returned his sonic screwdriver, but he might not have needed that if he hadn't had to take care of her.
As for checking someone's eyes, there are normally two things you can do following a head injury:
a) Move a finger back and forth, getting the person to follow it with their eyes. Normally, both eyes will move together, so if they move independently then that's a bad sign. Martha didn't do any finger waving.
b) Shine a light into one eye, to see whether the pupil contracts and then dilates again when the light is removed. Normally, only that one eye will respond to the light, so if both eyes react the same way then that's bad. It's also a bad sign if the eye you shine a light into doesn't react at all, although you have to choose the right location (e.g. not standing in bright sunlight). Unless Martha can make her eyes glow, she didn't do that test either.
So, bearing that in mind, I'm not sure what she did achieve by peering into Leo's eyes, I'm not convinced that she gave an accurate diagnosis, and if the diagnosis was accurate then I don't think that she treated it appropriately. All in all, not a shining example of first aid. On the plus side, it does give me extra material for my training video.
While I'm siding with Martha's mother, I also think that she had a good point about the fact that Martha has only just met the Doctor, so it's a bit soon for her to be falling in love with him. Granted, more time has passed for Martha than for the rest of her family (and she's less of a slapper than her cousin), but she does still seem to be jumping the gun a bit. In fact, borrowing a phrase from Wayne's World, I'd say that she seems to be moving into "psycho hosebeast" territory: she's convinced herself that she and the Doctor ought to be a couple, without any signs that he's interested in that, and then she's annoyed with him for taking her to the same place as Rose, because it seems like "rebound" behaviour. At this rate, she'll be getting annoyed with him for forgetting the anniversary of when they didn't have their first date! However, I'm going to give the writers the benefit of the doubt here, and say that this is a deliberate choice to set up drama in later episodes.
Ending on a positive note, I did like the sibling banter that went on at one point: Martha's mother complained that the whole mess was the Doctor's fault, but Leo said that it was actually Tish's fault (since she worked for Lazarus and had invited everyone else to the reception), so Tish elbowed him in the stomach.
Speaking of TV, there have been some problems with cable TV in the US:
Tots tune in to Disney Channel, get hardcore pornography instead
(as referenced in the latest Punch an' Pie strip).
And finally, on an unrelated note: I've now set up my LJ to screen anonymous comments, because I keep getting spam. At least this way the rest of you don't have to see it (if it takes me a while to delete it), but I may wind up blocking anonymous comments altogether if this keeps up. (I've been dutifully marking each comment as spam when I delete it, but I'm not sure whether the LiveJournal servers can do anything useful with that info.)