 Now surprisingly, Lewenhoek's very simple microscope, which allowed much greater magnification, allowed him to see and describe things that happen inside a cell. So he described bacteria that he found from scrapings from his mouth. And one of the things that he found was these little molecules or animalcules swam around in a solution. But if he sampled his mouth after having drunk a hot cup of coffee in the morning, they didn't swim around anymore. So these little animals were killed by his hot coffee. He really liked sampling from the environment around him. So he would take samples of pond water and describe many, many objects that he found swimming around in that water. And he also looked inside algal cells and described a spiral green spring that was contained within the cell, which was a very good description of a chloroplast, which is where photosynthesis takes place inside algal cells. So the advantage of his type of microscope, which allowed much greater magnification, was that he could clearly see inside the cell and started to describe the processes that can occur inside the cell. Hi. In this section we're going to talk about a replica of Lewenhoek's microscope, that Zeiss Company manufactured as a commemoration about 300 years since Lewenhoek actually published his work. Ryan Gunning, when he got hold of this replica of Lewenhoek's microscope, decided to try and see what he could see through it. And he took the Tradescantia stamen hairs and mounted them. So here we have the microscope, and there's a spike that is protruding, and that's what you impale your specimen on. This little lever here allows you to rotate the specimen around relative to the position of the lens. We have a long screw here with a turning handle that raises and lowers the specimen relative to the lens. And finally we have a third adjusting screw here, which moves the specimen towards and away from the lens so that you can get the specimen exactly in focus. So if you look at the microscope from the other side, you can see the little circular bead of glass which is the lens. Now the secret or the reason why Lewenhoek's microscope was so effective was that tiny bead of glass has a much greater magnification property than the larger lenses that Hook used in his illustrations. So the idea is we have our specimen that's mounted on the little hook. Let's have to get that positioned correctly. And then you would hold the microscope up to your eye with a source of light behind the specimen. So the light's coming through the specimen and you're looking at it through the lens. And this is really cool because it's quite tricky to see through, but what you can see is this little bead of blue balls joined end to end, which is the stamen hairs. Now I'm not an expert in using this microscope, so we're going to turn to Brian Gunnam's superb video footage which he took. And this is an experiment that we normally run in our first year biology labs. So we have here a plant which has these beautiful blue flowers and the stamen hairs, which are naturally coloured blue, can be mounted and observed. Normally we use a compound microscope, but Brian Gunnam managed to mount these and view them through Lewenhoek's microscope and take a video. So what's special about these cells is firstly they're filled with a big blue sack, which is the vacuole. And the natural blue dye in it allows you to see much more clearly inside the specimen without having to apply stains. And the tissue is only one cell thick, so you don't have to prepare, you don't have to section. You just mount the single stamen hair to be able to look into a cell. And as you peer inside the cell, you can see little particles, as if they're like cars moving along a highway, streaming along, moving around the cell. And this is called cytoplasmic streaming. Now, second specimen that we also use are giant algal cells. Now these single cells can be as large as several centimetres long. And these make wonderful specimens to also look through the microscope. And here is an example that Brian Gunnam also photographed using Lewenhoek's replica microscope. What you can see are the spiral arrangement of chloroplasts on the surface of the cell. And if we focus deeper into the cell behind the layer of chloroplasts, once again you can see these balls or globules of material being shuttled along through the cell. Again, the cytoplasmic streaming.