Henry Oldenburg wrote to Reinier de Graaf about the Royal Society's reception of Leeuwenhoek's first letter
Oldenburg wrote this letter on May 15 (O.S.) in London.
The Correspondence of Henry Oldenburg, vol. 9, pp. 653-654
Henry Oldenburg greets the very famous Mr. Regnier De Graaf M.D.
... You have done something that was extremely welcome to us in that you decided to impart to us the reflections of your countryman Leeuwenhoek concerning microscopes and the results he has achieved with their aid. I read over [to the Society] a translation of his observations made into English from the Dutch language and I gathered that our people approved of the man's diligence and outstanding precision, and were extremely anxious to be able to examine figures of the triple sting observed in the bee and of the limbs noted in the same insect.
Moreover, we desired that he would under your direction look more attentively through that new microscope upon the cicatricula [blastoderm] and chalaza of a fertilized but unincubated egg just as Malpighi and Croone examined it, discovering in it the first signs of the embryonic chick. Many other things will occur to you both (without need of advice) as being worthy of observation, concerning the structure of plants, insects, and the like that is to say, especially matters concerning the pores and forms of various bodies upon which the explanation of very numerous phenomena of great importance in physical science seems to depend.