Volume 1
Alle de brieven van Antoni van Leeuwenhoek / uitgegeven, geïllustreerd en van aanteekeningen voorzien door een Commissie van Nederlandsche geleerden.
- Antonie van Leeuwenhoek
- Date:
- 1939-
Licence: Public Domain Mark
Credit: Alle de brieven van Antoni van Leeuwenhoek / uitgegeven, geïllustreerd en van aanteekeningen voorzien door een Commissie van Nederlandsche geleerden. Source: Wellcome Collection.
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![[To Mr. Constantine Huygens, Seigneur of Zuilichem. Delft, April 5th 1674. Sir, When I was at your house some time ago, I told you that I had observed a cow’s milk, and had found that it consists of white, transparent globules floating in a wheylike fluid, and that I had observed blood from my hand, which I found to consist of red globules, also floating about in a wheylike fluid. This is to inform you that I have since examined my blood once more, this time with greater accuracy. In now find that the fluid in which the globules float are more like a crystalline1) than like a wheyish1) fluid. I also gave you my opinion on the manner in which hair grows, that is to say that it entirely consists of connecting globules, which I imagined I had observed in a hair taken from my eyelid; also, that it did not grow by expelling the globules at the extremity (as happens in the case of trees and plants, as shown by me) but that these corpuscles are joined to the hair at its beginning, namely 1) “Crystalline” is here opposed to “wheyish”, to indicate “clear” as contrasted with “somewhat turbid”. Oscillations in the limpidity of the plasma will occur, and depend, i.a., on the character of the food. [H.] As early as 1665 red blood-corpuscles were seen by Malpighi (Exercitatio de omento, pinguedine et adiposis ductibus. Opera omnia, 1687), but he took them for fat-globules. He corrected this mistake afterwards as is evident from his Diavium in the University Library of Bologna. (See O. T. Hult, Om Antony van Leeuwenhoeck och pioniarerna inom mikroskopien. Lychnos, 1937; p. 324 and F. Franchini, Marcus Malpighi. Commemorazione populate, 1930; p. 159.) Swammerdam also observed them (Biblia naturae II, 1738; p. 835) without making a further study of them. L. was the first to investigate them accurately. He repeatedly refers to them in later letters. It is, however, remarkable that L. describes these corpuscles as round, at the same time observing quite correctly that they show little colour if lying in a thin layer. The erythrocytes are flat, round discs, lenticular, double-concave, yellow- coloured. Not till much later did L. discover their real form (see i.a. the letters of March 3rd 1682, July 16th 1683, July 25th 1684 and July 9th 1700). It seems strange that L. should not have given figures of the blood-corpuscles in his first letters. [S.] Globules in milk and blood. Growth of hair, ill. 7. ill. 6.](https://iiif.wellcomecollection.org/image/b31364962_0001_0073.jp2/full/800%2C/0/default.jpg)
