Other and more direct allusions, however, occur to the art of serpent-charming. Thus the obduracy of the wicked is compared to "the deaf adder that stoppeth her ear; which will not hearken to the voice of charmers, charming never so wisely."[183] And the Aseverity of the Chaldean invaders is depicted under this imagery:--"Behold, I will send serpents, cockatrices, among you, which will not be charmed, and they shall bite you, saith the LORD."[184] Among the ancient Romans the Psylli, a people of Africa, and the Marsi, a German tribe who had settled in Italy, were reputed to have the power of charming serpents, and to be endowed with immunity from the results of their venom. Celsus, however, maintains that this power consisted in an acquaintance with the fact, now well known, that animal poisons are hurtful only when mingled with the blood. They may therefore be taken into the mouth with perfect impunity. With reference to so great an authority, however, there is more in the art and mystery of serpent-charming than this. When Lucian describes the Babylonian magician as walking abroad, and calling to him all the serpents that were near, with certain ceremonies, such as the utterance of sacred words from an ancient book, lustrations made with sulphur and a torch, and solemn marchings in a circle, and when he asserts that the venomous reptiles, _nolentes volentes_, presented themselves harmless at his feet,--he describes a scene which is sufficiently familiar to European travellers in Egypt and India. And so, when Silius Italicus speaks of Atyr, instructed how to disarm serpents of their dire venom, and to lull to sleep the terrible water-snakes with his magic touch, he refers, whether truly or falsely, to something of a more potent character than the feat by which Queen Philippa saved the life of her royal husband. Immunity from the poison of serpents, and serpent-charming, are two things. The former, so far as it depends on the natural law already mentioned, scarcely comes within the province of this work. But is there not an innate immunity residing in some persons, and even in some peoples, by which, without the operation of any recognised natural law, or even any effort, they are securely protected either against the bites of venomous serpents, or, at least, against the fatality which is the ordinary result of being bitten?