Various shell fossils were also used as talismans. Here the form generally determined the virtues they were supposed to possess. Some of these strange forms lent themselves to an interpretation in line with the primitive adoration of the life-giving forces of nature, and suggested the use of such fossils to cure certain special diseases. Other of these petrifactions retaining the form of the enclosing shell, especially those of circular shape, and with concentric rings, were believed to be of meteoric origin and to have fallen during thunder or rain; hence the names of brontia and ombria. A certain class of these fossils, with convolutions on the surface resembling the form of a snake, were called snake-eggs (ova anguina), and, very naturally, enjoyed the repute of preserving the wearer from poisons. All these varieties will be described in this and the following chapters.
While some believed that the toad-stone was vomited by the animal, others held that it constituted a part of the toad’s head. That this was the popular belief in Shakespeare’s time is shown by the well-known lines in his “As You Like It” (Act II, sc. 1):
Which like the toad, ugly and venomous,
Wears yet a precious jewel in his head.
De Boot, whose treatise was published about the time that Shakespeare wrote these lines, gives the following account of the result of his efforts to obtain a toad-stone according to the prescribed method:[[325]]
I remember that, when a boy, I took an old toad and set it upon a red cloth that I might secure a toad-stone; for they say that it will not give up its stone unless it sits upon a red cloth. However, although I watched the toad for a whole night, it did not eject anything, and from this time I became convinced all the tales concerning this stone were merely fond imaginings.
A stone called simply the “Indian Stone,” and said to be light and porous, is noted by pseudo-Aristotle, and to it is attributed the power to relieve those suffering from dropsy, by drawing the water to itself. If weighed after having been applied to the patient, the stone was found to have increased in weight in proportion to the amount of water absorbed, and when it was placed in the sun, water of a yellowish hue exuded, until, finally, the stone resumed its original appearance and weight.[[326]] Another and perhaps earlier authority gives the name “toad-stone” to this material.[[327]]
BVFONITES
Toad-stones. Natural concretions of claystone and limonite. From Mercati’s “Metallotheca
Vaticana,” Romæ, 1719.
The toad-stone was not only an antidote for poisons, but was also thought to give warning of their presence by becoming very hot. To fully profit by this strange quality, the wearer of such a stone was advised to have it so set in a ring that it would touch the skin; in this way he would be sure to have timely notice, if any poisoned food or drink were offered to him.[[328]] The writer who mentions this adds the following tale of the discovery of a toad-stone: