Griffith’s 1928 experiment

14:08>> Liverpool. >> Yeah. >> Shout out to all the Scousers out there. You never walk alone. [laughter] >> Frederick Griffith. Okay. He's he's at the Liverpool University and at the Liverpool Medical Institution. >> Okay. and he does a few experiments with bacteria and mice. >> And this is what he's doing. >> Back then we we knew that there were two types of bacteria of this particular strain called S nummon. I think it's basically pneumonia. >> Okay, it's pneumonia that affects mice. >> Okay, there's two types of these bacteria. There's a smooth strain which is the S and then there's a rough strain

14:48which is the R. Okay. >> And we know that the smooth strain kills mice. >> Okay. >> But the rough strain does not. >> Okay. You can inject the rough strain into mice, they'll live. The smooth strain into mice, they won't live. >> Okay? >> But here's the kicker. Here's the the genius of his experiment. What Griffiths did was he said, "Okay, can I turn the rough strain into the smooth strain?" >> Can you turn water into wine? >> Yes. In some sense, in some sense, here here's what he's doing. Like >> what what he can do is so if he puts the rough and the smooth strain together and then he puts it in a mice, they die. But

15:29that makes sense because you just put the smooth strain, the viralent form in the mice and they died, >> right? >> What he does was he he kills the smooth >> heat kills. >> Yeah. So he he he gets a bunch of bacteria that are really bad that are going to kill the mice and he kills them. >> I don't know what that means. Um, just heat it up. He lit. So, so he he literally turned turned the volume to 11. >> Yeah. >> On the heat. >> Yeah. He boiled them up. >> Literally literally just heat. >> Yeah. Just literally heated them up and it inoculated kind of the the fatal aspects of it. >> Yes. And now when he puts that into the mice, they still live. >> They still live, right? Because you've killed a bacteria. I see >> that makes sense.

16:09>> That makes sense. >> But here's the thing. This is the kicker. He takes that heat killed strain, that little sample that he has. Uh it's a you know, let's say it's in a test tube. He's he's put it into a really hot water bath. It's killed all the bacteria and he mixes that with the nonviolent type. >> Mhm. >> And then he puts that mixture >> into the mice. >> So he's taken the thing that's bad. >> He's boiled it. >> He's boiled it. >> And now he's done a little mix >> mixing with the stuff that was fine. >> That was fine. >> And then he puts that mixture in the mice and the mice die. Uh, so even when you boil, even when you heat, >> you heat it up, boil it all up, and still mix, there's something there's

16:50something there. >> There's something there. That's the thing. That's the thing. >> That's the thing. There's something physically there >> the that that has transformed, >> right, >> the nonviralent form into the one that kills mice. And it has nothing and it has nothing to do like it it's still present even after trying to have heated. Yes. Which the theory was that will kill any problematic. >> Yeah. That that's why that control was very important. Right. The control of let's heat up my um viralin form and then put that in the mice. >> Right. >> They don't die. >> They don't die. So, so I've killed a bacteria, but I've preserved something in that bacteria

17:31>> that is continuing to propagate >> that is continuing to propagate this ability to kill mice. >> Yep. >> Right. That this ability to be violent and that has gone and transformed the nice bacteria into the bad bacteria >> and gone and done the experiment. >> The point being there is something more fundamental than what we thought to be what is driving this process. >> Yeah. It's not just the bacteria. There's something inside the bacteria that is staying put that is going inside the the the non bad bacteria, the good ones, >> and replicating making them bad. [clears throat] >> And it that's okay, >> right? This is a very fundamental experiment. It's very simple. It's very

18:12simple, but it shows you that there's a physical element to this idea of ability. I want to just take a quick pause to point out like how sometimes simple or straightforward some of this early stage science sounds like.