At last one day, after the boy had been lying in this condition for a long time, getting neither better nor worse, always confined to bed, but with an extraordinary appetite--one day, while sadly revolving these things, and standing idly at his forge, with no heart to work, the smith was agreeably surprised to see an old man, well known for his sagacity and knowledge of out-of-the-way things, walk into his workshop. Forthwith he told him the occurrence which had clouded his life. The old man looked grave as he listened; and after sitting a long time pondering over all he had heard, gave his opinion thus: "It is not your son you have got. The boy has been carried away by the '_Daione Sith_,' and they have left a _Sibhreach_ in his place." "Alas! and what then am I to do?" said the smith. "How am I ever to see my own son again?" "I will tell you how," answered the old man. "But, first, to make sure that it is not your own son you have got, take as many empty egg-shells as you can get, go into his room, spread them out carefully before his sight, then proceed to draw water with them, carrying them two and two in your hands as if they were a great weight, and arrange them when full, with every sort of earnestness around the fire." The smith accordingly gathered as many broken egg-shells as he could get, went into the room, and proceeded to carry out all his instructions. He had not been long at work before there arose from the bed a shout of laughter, and the voice of the seeming sick boy exclaimed, "I am eight hundred years of age, and I have never seen the like of that before." The smith returned and told the old man. "Well, now," said the sage to him, "did I not tell you that it was not your son you had: your son is in Borracheill in a digh there (that is, a round green hill frequented by fairies). Get rid as soon as possible of this intruder, and I think I may promise you your son. You must light a very large and bright fire before the bed on which this stranger is lying. He will ask you, 'What is the use of such a fire as that?' Answer him at once, 'You will see that presently!' and then seize him, and throw him into the middle of it. If it is your own son you have got, he will call out to you to save him; but if not, the thing will fly through the roof." The smith again followed the old man's advice: kindled a large fire, answered the question put to him as he had been directed to do, and seizing the child flung him in without hesitation. The _Sibhreach_ gave an awful yell, and sprang through the roof, where a hole had been left to let the smoke out.