Besides the oath of Socrates, "by the dog," he is reported to have sworn variously by the goose and by the plane-tree. Those who argue in favour of the piety of the philosopher, explain that the habit was assumed as a foil to the irreverent mention of the gods that was then so universal. Lucian attaches an intelligible meaning to these flippant expletives, and represents Socrates as justifying their use. "Are you not aware," he is presumed to reason, "that the dog is the Anubis of Egypt, the Sirius of the skies; and in hell is the keeper Cerberus?" and Plutarch is also found to comment on the oath, "those that worship the dog have a certain sacred meaning that must not be revealed; in the more remote and ancient times the dog had the highest honours paid to him in Egypt." In the copiousness of the ancient swearing the notion of an oath accommodated itself to all the varieties of monstrous gods. The divinities Isis and Osiris were invoked in witness of a sacred pledge no less than the garlic, the leek, and the onion, and indeed every other deity which, as was said by the Roman satirist, grew and flourished in the market-gardens of Alexandria. We are admitted to a just appreciation of the levity of Athenian swearing through the medium of one of the most remarkable performances ever placed upon the stage, whether of the modern or the ancient world. When, returning from an expedition, Socrates repaired to the theatre to witness Aristophanes' comedy 'The Clouds,' he found himself portrayed upon the scene as the central figure of the drama. He was even represented swung up in a basket in his own thinking-shop and giving utterance to innumerable heresies and follies. When Strepsiades offers to swear by the gods, he is at once interrupted by Socrates in the basket, who reminds him that the gods are not current coin in his system of philosophy. "By what then do you swear?" asks Strepsiades; "by the iron money, as they do at Byzantium?" Unhappily the query remained unanswered. The result, however, of the Socratic influence is intended to be shown by the circumstance of Strepsiades subsequently swearing "by the mist!" and reproaching his son for taking oaths in the name of a deity of the outside world. Presently, on being importuned by a creditor for the return of twelve minae lent for the purchase of a dapple-grey horse, he is ready to swear any number of oaths "by the gods" that he is innocent of the debt. His opinions have in the course of this short dialogue undergone alteration. He feels justified in ridding himself of his obligation to repay the loan by making use of declarations which the philosopher has argued are no longer of any consequence. "And will you be willing to deny it upon oath of the gods?" screams the creditor. "What gods?" asks Strepsiades. "Jupiter, Mercury, and Neptune." "Yes, by Jupiter!" rejoins Strepsiades, "and would pay down, too, a three-obol piece besides to swear by them."