To Mr. Thomas Gale,

ANTONI van LEEUWENHOEK sends greetings.

MOST NOBLE SIR,

My last letter to you was dated the 13th of May original: "Tertio Idus Majas" — the 13th day of May in the Roman calendar, in response to which I received with a very grateful heart the great honor with which the most noble and learned gentlemen, the colleagues of the Royal Society, have favored me by admitting me as a member of their Royal Society. I would wish this most illustrious society to be greeted by you on many accounts; I add to these greetings some humble observations, which I hope will be not unwelcome to you, as well as to other philosophers At this time, "philosopher" referred to "natural philosophers," whom we would today call scientists..

I have often observed the dregs yeast which beer ejects, and I saw everywhere that it consists of globules Leeuwenhoek's general term for the microscopic round particles he discovered; here, he is describing yeast cells. floating through a transparent matter, which I judged to be the beer itself. I also saw as clearly as possible that each globule of the dregs consists again of six distinct globules, and these were of exactly the same size and shape as the globules of our blood.

Based on this observation, I decided to observe the beer at that time when it is poured from the basins intended for cooling (cooling vats) into the Large Tub * (vat) so that it may be stirred and ferment. Therefore, having taken some of this beer and poured it into two glass cups in which no liquid had ever been placed, I saw that it was mixed with many small particles, so much so that it was clearly cloudy. Some of them seemed to me clearly round, others irregular, and some exceeded others in size; it seemed to consist of two, three, or four of the aforementioned particles joined together, while others consisted of six globules, and these latter ones formed a solid globule of the dregs. Although I watched all of them with great desire—

• Note: This tub was so large that it could hold forty Bordeaux casks (hogsheads original: "Oxhoofden" — a Dutch unit of liquid volume); and each cask was sold for twelve Guilders.