Cicero, again, speaks of the ibis as being a very large bird, with strong legs, and a horny long beak, which destroys a great number of serpents, and keeps Egypt free from pestilential diseases, by killing and devouring the flying serpents, brought from the deserts of Lybia by the south-west wind, and so preventing the mischief which might attend their biting while alive, or from any infection when dead.
There are not unfrequent allusions in ancient history to serpents having become so numerous as to constitute a perfect plague; the dreadful mortality caused among the Israelites by the fiery serpents spoken of in Numbers is a case in point, and another[189] is the migration of the Neuri from their own country into that of the Budini, one generation before the attack of Darius, in consequence of the incursion of a huge multitude of serpents. It is stated that some of these were produced in their own country, but for the most part they came in from the deserts of the north. The home of the Neuri appears to have been to the north-west of the Pontus Euxinus, pretty much in the position of Poland, and I believe that at the present day the only harmful reptile occurring in it is the viper common to the rest of Europe. Diodorus Siculus[190] mentions a tradition that the Cerastes had once made an irruption into Egypt in such numbers as to have depopulated a great portion of the inhabited districts.
These stories are interesting as showing a migratory instinct occurring in certain serpents, either periodically or occasionally, and are thus to some extent corroborative of the account of the annual invasion of Egypt by serpents, referred to in a previous page. They also, I think, confirm the impression that serpents were more numerous in the days of early history, and had a larger area of distribution than they have now, and that possibly some species, such as the Arabian and flying serpents, which have since become extinct, then existed. Thus the boa is spoken of by Pliny as occurring commonly in Italy, and growing to such a vast size that a child was found entire in one of them, which was killed on the Vatican Hill during the reign of the Emperor Claudius. Yet at the present day there are no snakes existing there at all corresponding to this description.
Parallel instances of invasions of animals materially affecting the prosperity of man are doubtless familiar to my readers, such as the occasional migration of lemmings, passage of rats, flights of locusts, or the ravages caused by the Colorado beetle; but many are perhaps quite unaware what a terrible plague can be established, in the course of a very few years, by the prolific unchecked multiplication of even so harmless, innocent, and useful an animal as the common rabbit. The descendants of a few imported pairs have laid waste extensive districts of Australia and New Zealand, necessitated an enormous expenditure for their extirpation, and have at the present day[191] caused such a widespread destruction of property in the latter country, that large areas of ground have actually had to be abandoned and entirely surrendered to them.
It is interesting to find in the work of the Arabic geographer El Edrisi a tradition of an island in the Atlantic, called Laca, off the north-west coast of Africa, having been formerly inhabited, but abandoned on account of the excessive multiplication of serpents on it. According to Scaligerus, the mountains dividing the kingdom of Narsinga from Malabar produce many wild beasts, among which may be enumerated winged dragons, who are able to destroy any one approaching their breath.
Megasthenes (tradente Æliano) relates that winged serpents are found in India; where it is stated that they are noxious, fly only by night, and that contact with their urine destroys portions of animals.
Ammianus Marcellinus (who wrote about the fourth century A.D.) states that the ibis is one among the countless varieties of the birds of Egypt, sacred, amiable, and valuable as storing up the eggs of serpents in his nest for food and so diminishing their number. He also refers to their encountering flocks of winged snakes, coming laden with poison from the marshes of Arabia, and overcoming them in the air, and devouring them before they quit their own region. And Strabo,[192] in his geographical description of India, speaks of serpents of two cubits in length, with membraneous wings like bats: “They fly at night, and let fall drops of urine or sweat, which occasions the skins of persons who are not on their guard to putrefy.” Isaiah speaks of fiery flying serpents, the term “fiery” being otherwise rendered in the Alexandrine edition of the Septuagint by θανατοῦντες “deadly,” while the term “fiery” is explained by other authorities as referring to the burning sensation produced by the bite, and to the bright colour of the serpents.[193] Collateral evidence of the belief in winged serpents is afforded by incidental allusions to them in the classics. Thus Virgil alludes to snakes with strident wings in the line
Illa autem attolit stridentis anguibus alis.[194]
Lucan[195] refers to the winged serpents of Arabia as forming one of the ingredients of an incantation broth brewed by a Thessalian witch, Erictho, with the object of resuscitating a corpse, and procuring replies to the queries of Sextus, son of Pompey. There are other passages in Ovid and other poets, in which the words “winged serpents” are made use of, but which I omit to render here, since from the context it seems doubtful whether they were not intended as poetic appellations of the monster to which, by popular consent, the term dragon has been generally restricted.
I feel bound to refer, although of course without attaching any very great weight of evidence to them, to the numerous stories popular in the East, in which flying serpents play a conspicuous part, the serpents always having something magical or supernatural in their nature. Such tales are found in the entrancing pages of the Arabian Nights, or in the very entertaining folk-lore of China, as given to us by Dr. N. P. Dennys of Singapore.[196]