An Account of a Very Large Human Calculus, by Wm. Heberden M. D. F. R. S. and Fellow of the Coll. of Physic. Lond.

mitted in the above-mention'd Experiments, it might probably have been render'd pure by a much larger Dose of Lead than is usually applied for that Purpose. To my Memoir I might have added, that, attempting to cleanse a Parcel of the native Platina from the black Sand, wherewith it was mixed, I found that a great many of its Grains were attracted by the Magnet I made use of for that Purpose. This Circumstance I took notice of in a Letter to Lord Londale two Years ago. I am, Dear Sir, Your most obliged humble Servant, W. Brownrigg. XIII. An Account of a very large human Calculus, by Wm. Heberden M.D. F.R.S. and Fellow of the Coll. of Physic. Lond. Read Dec. 20. 1750. There is preserved in the Library of Trinity-College in Cambridge, a Stone taken from a human Bladder, which, for its uncommon Size, may deserve the Notice of his Society. It is of an oval Shape, flatted on one Side and its Surface is smooth. The specific Gravity plainly shews, that it is of an animal Origin; for its Weight is to that of Water only as 1,75 to 1. In order to get a true and well-attested History of this curious Stone, the Right Rev. Dr. Claggett, late Bishop of Exeter, was applied to, who was Keeper Keeper of the Library at the time when it was given, and likewise the Rev. Dr. Baker, who was then a Fellow of Trinity College, and entertain'd the Gentleman that brought it; and lastly, a Son in law of the very Person from whom it was taken. From their Accounts it appear'd, that this Stone was taken from the Wife of Thomas Raisin, Locksmith in Bury, after her Death, by Mr. Gutteridge, a Surgeon, of Norwich. She had felt much less Pain than might have been expected from so large a Stone; and might probably have liv'd much longer with it, if she had not thought herself well enough to attempt a Journey on Horseback; for, while she was riding, she was suddenly seized with violent Pains, that obliged her to be taken off the Horse immediately: After which she could never make Water, unless the Stone was first moved, and she continued in great Agonies till she died. This happen'd in the Reign of King Charles II. who being then at Newmarket, had the Stone brought to him; some Part of which was chipp'd off from one of its Ends, to shew the King that it consisted of various Coats formed one over another, as animal Stones usually do. Mr. Samnel Battely, who was Member of Parliament for Bury, had Possession of this Stone, either immediately, or very soon after the Woman's Death, and kept it till it was presented to Trinity-College, which was about the Middle of Queen Anne's Reign. This monstrous Stone weighs 33 Ounces 3 Drachms and 36 Grains, Troy Weight. There appears to have been at least half an Ounce broken off, on the Occasion casion before related; not to mention what it must have lost by mere Wear in fourscore Years. We are told, that they have in the Hospitals of Paris human Calculi weighing 34 Paris Ounces: But this in Trinity Library, even at present, weighs 34 Paris Ounces all but 9 Grains; and must have weigh'd considerably more when it was whole. Yet these are perhaps the heaviest that are any-where recorded; except that very extraordinary one mention'd by Dr Lister, in his Journey to Paris, p. 232; which he says was taken from a Monk A.D. 1690. and weighs 51 Ounces. This History may confirm to us the Usefulness of endeavouring to relieve the Violence of Pain in this Distemper, by altering the Position of the Stone in the Bladder, either with the Help of the Catheter, or by some proper Alteration in the Posture of the Patient; since, with respect to the Pain which it occasions, the Situation of the Stone appears to be of far greater Consequence than its Size. XIV. A Letter from the Rev. Charles Lyttelton LL.D. and F.R.S. Dean of Exeter to the President, concerning a non-descript petrified Insect. Read Dec. 20, 1750. THE curious Fossil I have now the Honour to exhibit to the Society, is as rare as its Figure is elegant; having been mention'd by none of our own Writers who treat on Fossils,