MAY 2007 – NO. 15
When Scrotum Humanum walked the earth
Robert Plot (1640-1696) was a Kent-born naturalist and chemist who was appointed first keeper of the Ashmolean Museum in 1683. Today much of his fame, or infamy, lies in his authorship of two volumes of observations on natural history and antiquities. His first book The Natural History of Oxfordshire was published in 1677 while his second The Natural History of Staffordshire appeared nine years later in 1686. He was, by all accounts (and there are not many), a rather odd man, but nevertheless a good and careful curator. However, in 1690, at the height of his fame he resigned his chair and keepership citing the low salary as good reason for leaving: it was better, he said, to do something rather than sitting around doing nothing for nothing. He retired with his new wife to Sutton Barne, where he had property, but enjoyed only six years of marriage before he died following complications with his urinary system.
The earlier reference to Plot's infamy derives from his interpretation of various English fossils which he described and illustrated for the first time in his two county books. Today young students of paleontology find these accounts fanciful, amusing, even startling. Plot described "screw-stones," "bulls' hearts," "horses' heads" and "star-stones" as well as a variety of other petrifications, now known to be the fossilized remains of once living marine organisms. He attributed their formation to some "plastic force" and did not regard them as being of organic origin. His "screw-stones" are either Lower Carboniferous crinoid stems or the internal molds of turritellid gastropods; his "bulls' hearts," or Bucardites as he called them, are the internal mould of the bivalve Protocardia; the "horses' heads" or Hippocephaloides are internal molds of another bivalve, Myophorella hudlestoni, from the Jurassic rocks at Headington near Oxford; and his "star-stones" are colonial corals. However, before condemning Plot for his ludicrous conclusions, one should look at the material: when viewed from a particular angle, some of the internal molds do look like horses' heads or hearts. With nothing with which to compare the material, it is not surprising that he reached the conclusions and attributions he did. Plot was important in the history of paleontology as he brought this material to the wider public and thus instigated a debate on the true nature of the material, this at a time when the organic origin of such curiosities was beginning to be appreciated across Europe. He also illustrated in his Oxfordshire treatise what he thought was the petrified thigh bone of a giant man. Nearly ninety years later in 1763, Richard Brookes redescribed Plot's specimen, which he named scrotum humanum — no guessing what portion of the human he thought it represented. Today, we know that this bone is the lower portion of a thigh bone from the dinosaur Megalosaurus. This animal, first described by the later Oxford academic William Buckland, was the first dinosaur to be given a name. Recently, it was suggested by the paleontologists and historians of science Bill Sarjeant and Beverly Halstead that in fact Buckland's name was invalid, and that Brookes' epithet Scrotum had priority as the generic name of this dinosaur! Sadly the International Commission for Zoological Nomenclature ruled in favor of Megalosaurus and Scrotum humanum is considered to be a nomen dubium which has now been consigned to the waste paper bin as a nomenclatural oddity.
Excerpted from The Chronologers' Quest: The Search for the Age of the Earth by Patrick Wyse Jackson. Copyright © 2006 by Patrick Wyse Jackson. Reprinted by arrangement with Cambridge University Press.
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