Figure 5 from van Leeuwenhoek 1700. “I thought convenient to get drawn one such before-mentioned particle, with the particles inclosed within it, as fig. 5 by E F sheweth.”

I usually try to comment on recent papers, but this time I’m going to go back a bit. More than a bit, really: 315 years, to what, as far as I know, is the first published report of Volvox (Van Leeuwenhoek, A. 1700. Part of a Letter from Mr Antony van Leeuwenhoek, concerning the Worms in Sheeps Livers, Gnats, and Animalcula in the Excrements of Frogs. Phil. Trans. Roy. Soc. London, 22:509–518). You know it’s old when half of the s’s look like f’s:

Great corn of fand indeed. Van Leeuwnhoek continues:

When I brought these particles before the magnifying glass, I did not only see that they were round, but that the outward skin of them was quite set over with many protuberant parts, which did seem to me to be triangular, and pointed towards the end; so that it seemed to me, that in the great circle of the roundness, stood such particles, all orderly and equally from each other; so that on a small body did stand about two thousand of the before-mentioned convex or protuberant particles.

Around 2000 triangular somatic cells…any ideas, Alexey?

This was to me a very pleasant sight, because the said particles, as of ten as I did look on them, did never lye still, and that their motion did proceed from their turning round; and that the more, because I did fancy at first that they were small animals, and the smaller these particles were, the greener was their colour; and on the contrary, in the greatest, that were as big as a great corn of sand, there was no green colour at all to be discerned on the outside.

These particles had each of them within included 5, 6, 7, nay, some to 12 small round globules, of the same shape as the body wherin they were included.

Another clue: up to 12 germ cells.

Among the rest, I did observe one of the greatest round parts somewhat larger, in a small quantity of water, before my eyes, and did perceive that the outward part began to open, and that one of the round particles was within it, and was of a delicate green colour, did slip out of it, and began to move in the water, as that part had done whereout it did come.

After this time did the first round particle remain without any motion at all, and, within a small time after did the second and the third part slip also out one after the other, and so did by degrees all come out after one another.

After the space of some days, the first round particle, as it was, united again with the water, for I could perceive no sign of it.

Sadnefs.

And what did also seem very strange to me was, that in all the motions I did see in the first round particle, I could not observe that the particles within did in the least change their place, altho the particles never came to touch each other, but did remain equally distant.

Most that should see these particles move in the water, would swear that they were live creatures; and that chiefly, if they did see them tumble about from one side to the other.

Now as there was a great many of the said round particles in one glass, wherein were also a great many living creatures, I did observe that in three days time they were all gone, so that I could see nor discern none of the said particles in the glass.

[emphasis mine] It seems strange that there should be any doubt that van Leeuwenhoek’s particles were alive; after all, he had seen them reproduce. It must have seemed quite alien, though: green like a plant, but moving under its own power like an animal.

I doubt that van Leeuwenhoek was the first to see Volvox. Colonies of some species can reach a millimeter or more in diameter, and all (I think) are easily visible to the naked eye. Someone prior to 1700 must surely have looked closely enough at pond water to see Volvox colonies rolling around, and if their eyesight was good, maybe even see some germ cells inside. Scientific publishing in the modern sense only got its start 35 years earlier, though, with the first issue of the Philosophical Transactions of the Royal Society, and van Leeuwenhoek was the first to see and report Volvox in detail. I think you can sense his excitement on first observing these ‘animalcules’ (“This was to me a very pleasant sight…”), not too different from any modern student who first sees a Volvox colony swim into their field of view in a sample of pond water.