Redi states that he himself possessed some of these stones, as did also Vincent Sandrinus, one of the most learned herbalists of Pisa. Redi describes them as “always lenticular in form, varying somewhat in size, but in general about as large as a farthing, more or less. In color some are black, others white, others black, with an ashy hue on one side or both,” etc.

Up to the present time no one has apparently identified what Tavernier referred to in speaking of snake-stones. It, however, occurred to the writer, after receiving a quantity of tabasheer from Dr. F. H. Mallet of the Geological Survey of India, who obtained it at the bazaar of the Calcutta Fair in November of 1888, that many, if not most of the Hindu snake-stones must have been tabasheer. Tabasheer is a variety of opal that is found in the joints of certain species of bamboo in Hindostan, Burma, and South America; it is originally a juice, which by evaporation changes into a mucilaginous state, then becomes a solid substance. It ranges from translucent to opaque in color, and is either white or bluish-white by reflected light, and pale yellow or slight sherry red by transmitted light. Upon fracture it breaks into irregular pieces like starch. As in Tavernier’s account of its clinging to the palate and causing water to boil when immersed, it actually has the property of strongly adhering to the tongue, and when put into water emits rapid streams of minute bubbles of air. It has a strong siliceous odor, but after absorbing an equal bulk of water becomes transparent like a Colorado hydrophane described by the writer several years ago before the New York Academy of Sciences.

Although tabasheer is mentioned in nearly all the textbooks, very little of it has reached the United States. It is highly interesting, since we have here an organic product scarcely to be distinguished from a similar opal-like body found by Mr. Arnold Hague in the geysers of the Yellowstone Park. Both tabasheer and the hydrophane were probably what was called “Oculus Beli,” “Oculus Mundi,” and “Lapis mutabilis” by Thomas Nicol, Robert Boyle, and other writers of the seventeenth century, and “Weltauge” by the Germans.

The great capacity of this substance for absorbing a fluid would undoubtedly render it as efficacious for the purpose of absorbing poison as any other known stone, providing the wound were open enough; and its internal use to-day as a medicine is possibly also due to this property.

Tabasheer, as known among mineralogists, is a corruption of the word tabixir, a name which was used even in the time of Avicenna, the Grand Vizier and body surgeon of the Sultan of Persia in the tenth century. It played a very important part in medicine during the Middle Ages. As to its origin, Sir David Brewster^[468] says that tabasheer is only formed in diseased or injured bamboo joints or stalks.

Guibourt^[469] differs from Brewster, inasmuch as he attributes the different rates of growth to the fact that when there is a superabundance of sap the tabasheer is formed from the residuum. More recently, Henry Cecil^[470] says, “In the onrush of tropical growth in the young shoot, nature, after flooring the knot, has poured in, as it were, sap and silica sufficient for a normal length and width of stem to the knot next above it. But by some check to the impulse, or by irregularity of conditions, the portion of stem thus provided for is shorter or narrower than intended, and the unused silica is left behind as a sediment, compacted by the drying residuum sap.”

This latter view is sustained by Dr. Ernst Huth, who discusses the name, history, origin, and reputed virtues of this substance with much fulness.^[471] In regard to its use in medicine during the Middle Ages, he quotes a remarkable list of applications to the ills that flesh is heir to.

Here it is cited as a remedy for affections of the eyes, the chest, and of the stomach, for coughs, fevers, and biliary complaints, and especially for melancholia arising from solitude, dread of the past, and fears for the future. Other writers speak of its use in bilious fevers and dysentery, internal and external heat, and injuries and maladies.

The writer has examined a large number of so-called madstones, and they have all proved to be an aluminous shale or other absorptive substance. But tabasheer possesses absorptive properties to a greater degree than any other of the mineral substances examined, and it is strange that it has never been mentioned as being used as an antidote. It may be confidently recommended to the credence of any person who may desire to believe in a madstone.

The writer believes that Tavernier’s snake-stones may all have been tabasheer, or again, while some of them were of this substance, others may have been artificially compounded by the authorized dealers of the Brahmin caste. The instance he gives of the successful use of such a stone is not altogether incredible, as, should one of the less active poisons be sucked out of a wound shortly after this were inflicted, a cure might well be effected. In view of the great difference in the virulence of poisons and the varying degrees of the sensibility to toxic effects, it is not strange that the snake-stones should sometimes seem to give good results. Tavernier states that these stones were brought to India by Portuguese soldiers returning from service in Mozambique.^[472] For successful use a pair of them were needed, so that, when applied to a snake-bite, as soon as one became saturated with the venom the other could be immediately substituted. To have them always at hand, those natives fortunate enough to own a pair of pedras de cobra carried them about in a little bag.^[473]

A curious traditional belief is current in some parts of India, notably in Ceylon, to the effect that the male cobra, during the night, uses a certain luminous stone to lure its prey and to attract the female. This is probably the chlorophane, a variety of fluorite, a substance which shines with a phosphorescent light in the darkness, and this quality, quite mysterious in the eyes of the natives, may have induced them to associate the stone with the snake, the epitome of all subtlety and cunning. Serpent-stones were supposed to exist in both ancient and medieval times, and the belief in their existence is widespread among many races of mankind.

A chlorophane is also found in the microlite localities of Amelia Court House, Virginia. The writer made a series of experiments and noted that some of these specimens emit a phosphorescent light at a low temperature. The material occurs in Siberia, and Pallas describes a specimen from this locality. When subjected to the heat of the hand, it gave out a white light, in boiling water a green light, and when placed on a burning coal a brilliant emerald-green light, visible at a considerable distance. Similar phenomena have been observed by the writer, who has found that very slight attrition, even the rubbing of one specimen against another in the dark, will produce phosphorescence.^[474]

The real or supposed virtues of the “snake-stones” of Ceylon are detailed at considerable length by the great Dutch naturalist, Rumphius. After noting the old tale that the “natural” snake-stones came from the cobra de capello (Serpens pilosus), he proceeds to relate the information he had been able to gather regarding the “spurious” stones of this type. These were fabricated by the Brahmins, the process being kept a profound secret; indeed, there were those who asserted that the Brahmins themselves had lost the art, as this had been possessed by but a single family which had died out, leaving the secret unrevealed. Rumphius describes these artificial stones as usually round and flat, the size varying from that of a half-shilling piece to that of a two-shilling piece. Some were of lenticular form and a few were oblong; all had a white spot in the middle. In making the application, the bitten spot was first pricked until it bled, whereupon the stone was immediately laid on and allowed to remain until it dropped off of itself “just as a leech would do.” So intense was its absorbent activity that it would sometimes break, in which case a substitute had to be quickly applied. The saturated stone was placed in milk and the absorbed venom was thus drawn out, turning the milk blue.^[475]

One of the tales of the Gesta Romanorum treats of a serpent-stone of singular medicinal virtue. According to the story—which is, of course, a mere legend—a certain Theodosius, who “reigned in a Roman city,” was a most prudent ruler, but was afflicted with blindness. In his care for the welfare of his subjects he had decreed that when anyone who desired justice rang the bell at the palace gate, a judge must forthwith appear and try his case. Now it happened that a serpent had its nest near the bell-rope, and one day, while the reptile was absent, a toad took possession of the nest. Returning and finding the nest occupied, the serpent,—evidently a worthy descendant of the original serpent of Paradise, “more subtle than any beast of the field,”—wound its tail about the bell-rope and pulled the bell. When the judge appeared, as in duty bound, he was struck by this strange spectacle, and reported it to the emperor, who told him to right the wrong which had been done, directing him to expel and kill the toad. Not long after, the serpent made its way into the palace and entered the emperor’s room, bearing in its mouth a small stone. Proceeding to the emperor’s couch, it crawled up, raised its head above the emperor’s face and dropped the stone upon his eyes. As soon as the stone touched the eyes, the emperor’s sight was restored. The serpent disappeared and was never seen again.^[476]

A representative type of “madstone” is a concretionary calculus occasionally, but very rarely, found in the gullet of male deer. In form it bears a resemblance to a water-worn pebble and is usually of oblong shape, the largest specimens being 3 inches in length and 1½ inches in width. The chemical analysis of Dr. H. C. White showed that the chief component was tricalcic phosphate. His experiments demonstrated that while such a concretion would absorb water to the amount of 5 per cent. of its own weight, the quantity of blood or other fluid it was able to absorb only amounted to 2.3 per cent. of its weight. When immersed in water, after having been placed on a wound caused by the bite of a venomous creature, the liquid absorbed was given out so as to discolor the water, and the material exuded was found to be of toxic quality. However, experiments with animals that had been bitten by snakes or other reptiles, failed to show that the stone exercised any curative effect. Dr. White states that he has in his possession a “madstone” dating from 1654, but this is of a different type, being a porous sandstone.^[477]

Even in South Africa snake-stones are known, but it appears that the few specimens reported had been brought thither from the Dutch East Indies; one such stone had been handed down for generations in a Dutch settler’s family. From their appearance some of these snake-stones were judged to be pieces of burnt hartshorn. A Boer farmer owned an amulet of this kind that he would loan from time to time to neighbors who might have need of it. On one occasion, when the daughter of an English hunter had been bitten by a snake, the father sent off a man on horseback to borrow this snake-stone. Owing to the unavoidable delay, some hours elapsed before it could be applied to the wound. The girl recovered after its use but the wound did not heal satisfactorily, and this was attributed to the length of time that had intervened between the attack of the snake and the use of the remedial stone.^[478]

In December, 1887,^[479] the writer described a white opaque variety of hydrophane with a white, chalky or glazed coating, which had recently been brought from a Colorado locality. The absorbent quality of this stone is quite remarkable, and when water is allowed to drop on it, it first becomes very white and chalky, and then gradually perfectly transparent. This property is developed so strikingly that the finder proposed the name “Magic Stone” for the mineral and suggested its use in rings, lockets, charms, etc., to conceal photographs, hair, and other objects, which the wearer wishes to reveal only as caprice dictates.