Well, I think we had arrived at the possible functions of lysosomes and I was telling you how abysmal my ignorance of cells was. And so I had to take... to start reading a little and found out, to my chagrin, that lysosomes had been known for almost a century, before I so-called discovered them. They had been known, of course, under different names; they were first known as food vacuoles, in protozoa. Protozoa feed with a rather complex mechanism sometimes and then they digest their food into pockets which the old morphologist described as food vacuoles, but really belonged to the lysosome family. And then a man called Ilya Mechnikov, who was a Russian zoologist who, for political reasons, eventually migrated to the Pasteur Institute in France... Mechnikov, who had witnessed the intracellular digestion by... by protozoa but also had seen cells in some small transparent animals that he watched in the microscope... seen cells that, sort of, were chasing after foreign objects, had come to the conclusion that those cells actually acted like the protozoa but they would eat invading bacteria, and that they would be involved in immunity, and he studied... those were mostly white blood cells, and he invented the word phagocytosis, which meant eating by cells. And he described how macrophages and white blood cells would eat bacteria and foreign objects and eventually break them down by what he called cytases. As you know, he got a Nobel Prize for that in 1915 [sic], which he shared with Ehrlich, and then another... other workers – I forget the name now – described a similar mechanism which was the taking up of droplets of fluid by cells, and they called it pinocytosis, which means drinking by cells. And then other workers had described granules of one sort or another, in various kinds of cells, and these granules would stock up with all kinds of different substances; they called them storage granules, and some of these granules... I mean, what was also observed that certain dyes would concentrate in these granules – nutro-red, for instance. Ehrlich had described this uptake of nutro-red which was concentrated in small, little granules in the cells. And so it turns out that all these observations came together under the same heading, uptake, which I called endocytosis eventually and digestion in lysosomes.