An attribute of St. Cecilia, St. Euphemia, and many other saints, either because they trampled on Satan, or because they miraculously cleared some country of such reptiles. (See Dagon.)
The brazen serpent gave newness of life to those who were bitten by the fiery dragons and raised their eyes to this symbol. (Numb. xxi. 8.)
It is generally placed under the feet of the Virgin, in allusion to the promise made to Eve after the fall. (Gen. iii. 15.)
Satan is called the great serpent because under the form of a serpent he tempted Eve. (Rev. xii. 9.) It is rather strange that, in Hindu mythology, hell is called Narac (the region of serpents). (Sir W. Jones.)
O wave, Hygeia, o'er Britannia's throne Thy serpent-wand, and mark it for thine own.
Jupiter Ammon appeared to Olympia in the form of a serpent, and became the father of Alexander the Great.
When glides a silver serpent, treacherous guest! And fair Olympia folds him to her breast.
Jupiter Capitolinus, in a similar form, became the father of Scipio Africanus.
(1) Of wisdom. “Be ye therefore wise as serpents, and harmless as doves” (Matt. x. 16). (2) Of subtilty. “Now the serpent was more subtil than any beast of the field” (Gen. iii. 1). It is said that the cerastes hides in sand that it may bite the horse's foot and get the rider thrown. In allusion to this belief, Jacob says, “Dan shall be ... an adder in the path, that biteth the horse's heels, so that his rider shall fall backward” (Gen. xlix. 17).
It is said that serpents, when attacked, swallow their young, and eject them again on reaching a place of safety.
Thomas Lodge says that people called Sauveurs have St. Catherine's wheel in the palate of their mouths, and therefore can heal the sting of serpents.
The Bible also tells us that it stops up its ears that it may not be charmed by the charmer. (Ps. lviii. 4.)
(2) Of eternity, as a corollary of the former. It is represented as forming a circle and holding its tail in its mouth.
(3) Of renovation. It is said that “the serpent, when it is old, has the power of growing young again `like the eagle,” by casting its slough, which is done by squeezing itself between two rocks.
(4) Of guardian spirits. It was thus employed by the ancient Greeks and Romans, and not unfrequently the figure of a serpent was depicted on their altars.
In the temple of Athen'a at Athens, a serpent was kept in a cage, and called “the Guardian Spirit of the Temple.” This serpent was supposed to be animated by the soul of Ericthonius.
Therefore think him as a serpent's egg Which, hatched, would (as his kind) grow dangerous.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894