The “pretious stone” theory that we have already encountered in one or two other cases, the toad being the most notable, is in full force again amongst the various strange notions concerning serpents. The recipe for its possession, given by Jacobus Hollerius, is simplicity itself, as it is merely necessary that the “snake be tyed by the tayle with a corde, and hanged up, and a vessell full of water set below; after a certayne time he will avoyde out of his mouth a stone.” The stone is of great medicinal value; for instance, “it fullye and wholelye helpes the partye that hath the dropsye,” by merely being attached to the body of the sufferer, and in divers other ways that we need not stay to particularize, proves itself a stone of price. Jordanus, amongst his other Indian experiences, came across serpents with horns, evidently the cerastes or horned viper, and others with precious stones. Tennant tells us that the Cingalese believe that the stomach of the cobra contains a stone of inestimable value, and this belief, absurd as we deem it, is really hardly more far-fetched than such a story as pearls being found in oyster-shells would appear to a man who heard it for the first time. Snakes and serpents, like most other repulsive things, have found their way into the pharmacopœia and the menu. Galen tells us that the Egyptians used to eat vipers as other people did eels, and it is a very old-world superstition that viper’s flesh is an antidote to the viper’s poison. In classic and mediæval days a famous remedy, originally known as mithridate or theriaca, and later on as Venice treacle, was held to owe much of its virtue as a vermifuge and antidote to all kinds of poison to the vipers that formed one of its ingredients. It was retained in the London Pharmacopœia until about a hundred years ago. Its constituent parts changed somewhat from time to time; at one period we see it contained seventy-three ingredients. The vipers were added to the horrible mess by Andromachus, the physician to the Emperor Nero,[121] and became a leading element in the prescription. The name treacle was at one time applied to any confection or syrup, and it is only in these latter days that the name has become associated exclusively with the syrup of molasses: it is derived from the Greek Therion, a name given to the viper, so that the schoolboys’ lunch of bread and treacle is the direct etymological outcome of the abominable adder’s broth of the Roman emperor.[122]