Visited by Alexander Stuart and two Scots gentlemen
Alexander Stuart was a Scottish ship's surgeon who, in this 30s, was studying for his medical degree from the university in Leiden. Stuart had been encouraged to further his education by Hans Sloane, with whom he had corresponded and who had published several of Stuart's articles in Philosophical Transactions. When he visited Leeuwenhoek as a student, Stuart had a recommendation letter from Hans Sloane, and a year's worth of Philosophical Transactions to deliver.
Leeuwenhoek gave Stuart and his two Scottish friends a glimpse into his cabinet of curiosities. He showed them the blood circulating in the tail of an eel. Stuart reported back to Sloane about the visit, but without much detail.
Stuart was one of the first visitors for whom Leeuwenhoek used his newly developed fish viewer (viskijker). At the end of the letter of 14 January 1710, Leeuwenhoek described the new device in detail. It is the same one that Leeuwenhoek used when Uffenbach visited later that year. Uffenbach gave a description that added some details. As well, he provided a drawing of both the front and the back of the device, though it was not published until 1753.
Stuart visited Leeuwenhoek again in summer 1711.
He also gave Leeuwenhoek a printed copy of one of his own student dissertations. It was perhaps on the same subject as was his final dissertation, the movement of muscles, also a concern of Leeuwenhoek.
Leeuwenhoek's Letter L-474 of 14 January 1710 to the Royal Society begins,
Through Mr Stuart I have received the six different Transactions, a present for which I am highly grateful, and I wish I may be able to be of some use to the Very Noble Sirs.
Mr Hans Sloane in his missive recommends Mr Stuart to me as a gentleman with a thirst for knowledge, who has travelled through many countries, and I have civilly received the said gentleman and also two Scotch gentlemen accompanying him. And I will so receive all those who have a letter of recommendation from Mr. Sloane. But if I were to receive everyone coming or trying to come to my house, I should have no liberty and should be as it were a slave.
I have shown the said gentlemen, among other discoveries, the circulation of the blood in an eel, and in particular how the blood dropped into the veins as it were through a valve, which movement we call a pulsation . Although the evening was falling when they came to me and they therefore had to make shift with candle-light (which I avoid, in particular for seeing the flow of the blood), all three saw it so clearly that they told me that they could bear witness to this.
And Mr. Stuart said more than once that he would write about it to Mr. Hans Sloane, for I think that in England I shall meet with even more contradiction than here in Holland, where I have shown it to several gentlemen, among others to three of the most distinguished gentlemen at the court of His Majesty ... , who in the late summer honoured me by coming to me in order to see some discoveries, among other things the circulation of the blood dropping through a valve into the veins, which they saw with great pleasure flowing in vigorously, and they observed the circulation of the blood with the greatest pleasure, and granted me that the pulsations took place in the veins.
