44	NATURAL HISTORY OF GEMS.
	white, which is the best, and the dark with a bluish tinge with the figure of an eye upon it.* If swallowed it was a certain antidote against poison, in its passage through the bowels driving out all noxious matters before it. More than a century later Vossius asserts (De Phys. Christ, vi. 19) that it was usual to take the Bufonites (Toad-stone) in; drink before meals, to counteract any poison that might be administered in the dishes ; a singular dinner-pill, exempli-fying the very uncomfortable state of society in those timea. It was also believed to burn the skin, at the mere presence of poison, if worn set open in a ring so that the stone should touch the finger ; besides which, it was good against all complaints of the stomach and kidneys if so carried. For these virtues, says De Boot, it is much worn in rings, ia spite of its ugly colour : a fact which innumerable examples remain to confirm. Nevertheless, this invaluable guardian sold cheaply enough : "the price asked by the vendor being regulated by the eagerness of the purchaser to possess it." Chinese porcelain also in the times of Vossius was supposed to fly into pieces when a poisoned draught was poured into it. Erasmus, in his ' Peregrinatio Eeligionis ergo,' thus describes a famous Toad-stone dedicated to Our Ladye of Walsingham :—" At the feet of the Virgin is placed a gem to which no name has yet been given among the Greeks or Romans, but the French have entitled it after the toad, inasmuch as it represents the figure of a toad so-exactly that no art of man could do it as well. And the wonder is so much the greater, that the stone is very small: the figure of the toad does not project from the surface, hut shines through as if enclosed in the gem itself. And some, no mean authorities, add that, if the stone be put into vinegar, the toad will swim therein and move its legs." * The brown marks, seemingly produced by oxide of iron, observable on some of these fossils.