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Clifford Dobell's labor of love: Antony van Leeuwenhoek and his 'little animals'Author: P. Pennywagon, Ph.D. (firstname.lastname@example.org)
Copyright © 2010 Mednansky Institute, Inc.
Dear Reader: …meet Mr van Leeuwenhoek and shake him by the hand and hearken to what he has to say. When you have done that, you will not only know the true meaning of that misused term 'scientific research', but you will also realize that you have already gone further along the path of peace and progress than some of the more sophisticated people… From 'The Author's [Clifford Dobell] Epistle to the Reader: Introducing Mynheer Antony van Leeuwenhoek of Delft in Holland, Fellow of the Royal Society of London in England.'
Mezzotint portrait of Leeuwenhoek by Johannes Verkolje (1650-1693)
Leeuwenhoek is depicted holding one of his magnifying-glasses
'Antony van Leeuwenhoek and his little animals: Being Some Account of the Father of Protozoology and Bacteriology and His Multifarious Discoveries in These Disciplines' was published in 1932 which coincided with the 300th anniversary of Antony van Leeuwenhoek’s birth. This masterpiece results from twenty-five years of vehement 'occupation' by Clifford Dobell who learned, loyalty obliges, seventeenth-century Dutch, the only language known to Leeuwenhoek.
Clifford Dobell, a respected microscopist, protozoologist and bacteriologist himself, recovered from both published and unpublished records Leeuwenhoek's observations on the protozoa and bacteria. He chronicled Leeuwenhoek's great discoveries objectively, in fact in Leeuwenhoek's own words. Leeuwenhoek's accurate observations and ingenuous writings undoubtedly impressed Dobell greatly. His praise for Leeuwenhoek is displayed firmly as he writes …I have read enough to realize that those people who ridicule him are generally ignorant, and usually reveal their own incompetence in the very act of denouncing his. Readers of 'Antony van Leeuwenhoek and his little animals' should be overwhelmed by Dobell's labor of love. Lastly they should realize Leeuwenhoek's contribution in laying the foundations for many disciplines. Thus true lovers of learning should value and cherish Dobell's legacy.Representation of a Leeuwenhoek's 'microscope' by Clifford Dobell
Fig. 1 shows the instrument from the back, Figs. 2 and 3 are details, Fig. 4 is a longitudinal section
The minute biconvex lens (l, Fig. 4) was mounted between two thin oblong metal plates
The socket angle-piece (Fig. 3) was attached behind the lower end of the plates by a small thumb-screw (S, Fig. 4)
Samples of Leeuwenhoek's remarkable and pioneering observations in his own words are reported below, as found in Dobell's book.
Excerpts (in bold) from a letter to the Royal Society dated October 9, 1676:
I saw more animalcules that had the figure of a pear, and two or three animalcules with tails. And I perceived at this time that the pear-shaped animalcules kept not against the surface of the water, like the other creatures, but that they swan a bit deeper under water. According to Dobell, animalcules with tails refer to Vorticella.
These curiosities of mine I divers times followed up further; and at last I saw very plainly, among other things, that from an eel which I had broken across the middle, there came out four distinct small eels, each twisted on itself, very nice and pretty, and each bigger than the one following: and the biggest, which came out first, lay and lived, and wrenched itself loose, and remain alive a little while. A note by Dobell indicates: These were the first observations ever made on the reproduction of Anguillula.
Eels in vinegar (Anguillula aceti) as represented by Robert Hooke in Micrographia, 1665
"That is, they were shaped much like an Eel, save only that their nose A, (which was a little more opacous then the rest of their body) was a little sharper, and longer, in proportion to their body, and the wrigling motion of their body seem'd to be onely upwards and downwards, whereas that of Eels is onely side wayes: They seem'd to have a more opacous part about B, which might, perhaps, be their Gills; it seeming always the same proportionate distant from their nose, from which, to the tip of their tail, C, their body seem'd to taper." Robert Hooke
In a letter to Hendrick van Bleyswyk dated February 9, 1702:
A body is pictured with its contained particles (Fig. 2, EF)
Leeuwenhoek compared the little round bodies found in the bigger ones to seeds
Image Copyright © 2003 Wim van Egmond, image use with permission
See Wim's Volvox, one of the 7 Wonders of the Micro World
As I aim at nothing but Truth, and, so far as in me lieth, to point out Mistakes that may have crept into certain matters; I hope that in so doing those I chance to censure will not take it ill: and if they would expose any Errors in my own discoveries, I'd esteem it a Service; all the more, because 'twould thereby give me Encouragement towards the Attaining of a nicer Accuracy. – Antony van Leeuwenhoek, December 25, 1700
'The "Delft School" and the rise of general microbiology' by C. B. van Niel, in Bacteriological Reviews, 13:161-174, 1949 (free PDF at the Archive of Microbiology and Molecular Biology Reviews)
Note on Leeuwenhoek's first record of Mendelian dominance: Mendelism in the Seventeenth Century (PDF) by Clifford Dobell, Nature, 94, 588-589, 28 January 1915 (Payment is requested to read the article in full if you do not have a subscription to Nature)
MICROGRAPHIA by Robert Hooke, 1665, EText-No 15491 at Project Gutenberg
Two Leeuwenhoek-type microscopes at the Whipple Museum of the History of Science, University of Cambridge, UK