I HaveI have been waiting a considerable time for a further and fuller Account of the Virtues of the Ostracites, from Dr. Home of Barwick, from whom I had the first Account of its being so extraordinary a Medicine in the Nephritis, but as yet have not got all the Satisfaction that I would have in the matter. However, lest you should think I forget to make a Return to your last obliging Letter, I rather choose to send you the following Account, imperfect as it is, than make you wait any longer for a better. (82)

Dr. Home, in a Letter to me in November last, tells me, ‘That he never us’d this Medicine to any that he knew to be troubled with a Confirm’d stone (being perswaded that no Medicine can break a large stone) but only to such as were afflicted with Gravel or small Stones; that some of his Patients were cured without evacuating any gravel or Stones at all, that others evacuated both: That it never does its Work suddenly, (being not remarkably Diuretick) but that it rather dissolved the little Stones than forced ‘em. That none that he ever gave this Medicine to, however grievously and frequently afflicted before, have ever been troubled with Nephritick pains since; That his manner of giving it, is in fine pouder mixed with about a third part of flores Chamomel: Dose from half a Dram to one Dram in White-wine. That the greatest Dose is often apt to offend and nauseate the Stomach; That he once gave it alone with a weak infusion of Chamomil Flowers, in White-wine after it, but that this did not so well.’

Thus far he. I can say but little yet of my own Knowledge of this Medicine, having had it but a short while, and not us’d it yet to any but one Gentlewoman, whose frequent and violent Fits of the Gravel, made her lead a Life uneasy enough. I gave her this Medicine not mixed with flores Chamomel (for at that time I was unacquainted with Dr. Homes's manner of giving it) but with poudered Semina Saxifrag. I cannot say, that since she used this Medicine she never had any Returns of her pains, but she neither has them so violent, nor so frequently; and whenever she is threatned with them, she most certainly finds ease by that time she has taken three Doses of her Powder: And she has since the use of this Medicine voided a great many small Stones: But the reason perhaps why she is still threatned with the (83) Return of her Nephritick Pains, is, that she has never follow’d her Medicine Throughly, but upon the third Dose, finding such certain Ease, she gives it over, till a new Fit forced her to use it again. But however, this having done so much more for her already, than any thing she ever met with before, she is so pleas’d with it and speaks such great things of it, that I believe she will soon furnish me with opportunities enough of giving it a fair and full Tryal; and when I know more of it, you may expect to hear further. In the mean time it may not perhaps be amiss for you to be using it your self; and I dare promise you, that you’ll find somewhat in it, that will make you set a Value upon it.

I take this Shell to be that which you call Ostracites maximus rugosus & asper; and which you have with the utmost exactness described. It burns to a Lime as other Shells do, and as the Selenites (tho’ weakly) does. It yields no Volatil Salt, tho’ I try’d it in a naked Fire; nor does common Oyster-shells, fresh taken and used, afford above half a Scruple of a Liquor somewhat moderately Urinous, from four Ounces of Shells. And it may be, if they were long dryed and exposed to the Weather, they would loose even that, and yield no more Volatil Salt than the Ostracites. I confess I was somewhat surprized at this matter; since there are who say, that even the other Shells, that are commonly call’d petrify’d, yield a Volatil Salt: and I had my self from the Shells of Crustaceous Fishes, (particularly of Lobsters) had a Volatil Salt and fetid Oyl in no inconsiderable quantity, even in a Sand Furnace. But these sort of Shells differ from other Shells (as you have exactly observed) in this too, Quod in his umbo ad cardinem leviter rostratus est, qui tamen in Ostreis paulùm aliter est. They differ too in their specifick Gravity, (84) These being more ponderous than common Oyster-shells, and somewhat near the specifick Gravity of the Selenites. But indeed they differ one from another in Gravity, as well as from other Shells, as they partake more or less of a Tophaceous Substance that coats many of ‘em on the inside, and which perhaps may be somewhat akin to the Selenites. And whether they may not have many other very different qualifications one from another, according to the several different Beds they are found in, I think there may be some reason to doubt. I have observed some such differences among the Cornua Ammonis, having had one or two small ones from our Coal pits here, that had a considerable mixture of the Pyrites; whereas these that are found about Whitby, approach, I think, more to the nature of the Alum-stone; and perhaps the Cornua Ammonis of the Ancients were found in Beds of somewhat yet more valuable; since Pliny says they were of a Golden Colour, and were reckoned, inter Sacratissimas Æthiopiæ gemmas. I know Agricola, [De ortu & causis Subterraneorum, lib.iv.] accounts for this Golden Colour after another manner: Cornua Ammonis inquit succo aluminis infecta aurei coloris fiunt. And I am ready enough to think, that there is some truth not only in this Observation, but in what he immediately adds, Idem inquit & aliis quibusdam lapidibus accidit. For I cannot but attribute the extraordinary appearance of Colours in the Peacock-tail Coal, to its being infected with the Succus Aluminis, having seen some pieces of this pretty sort of Coal, shoot into true and genuine Alum. Yet I cannot take this to be all the reason of the Golden Colour of the Cornua Ammonis of the Antients, since I think, if this had been all, they had never been numbred, or deserved a place among their Gems.

(85)

But be that matter as it will, I think its time to put an end to a Letter, that’s already grown much longer then was design’d; I shall therefore add no more concerning these Shells, being unwilling to burn my Fingers with that intricate and perplext question, What they are? All that I shall say of this matter shall be only this; If they be real Shells, their being found in such different parts of the World, and at such great distance from any Sea, may serve for a fair and convincing Argument of the Universality of the Deluge. And if they be not Shells, but only stones form’d by (what some People call) Fanciful and sporting Nature, we may at least conclude thus much from it, That since even these Lusus Naturæ, these Freaks, and random strokes of Nature, have not only a Beauty, but a real use, that nothing in Nature is made in vain: And that many other Fossils that we now contemn as toys and trifles, fit only for furnishing out a Musæum, may have other remarkable Virtues, that may in time bring even them to be taken notice of, and valu’d, as well as the long neglected and despis’d Ostracites.