"I don't know that I have," said Robinson. "Well, if you do you will notice the same yellow light flash into his eyes, and the sudden change of expression that I saw in the eyes of our friend Sing. It was gone in a moment, however, and he was again smiling sweetly. "'I understand he found it to consist principally of common salt.' "'Quite so,' answered Sing; 'but he must have discovered that it also contained something else?' "'That is true,' I answered, 'there was a small amount of vegetable matter which gave it a yellow color.' "'That is the true Elixir,' said Sing; 'salt is merely necessary for the results. You, as a scientific man, know that the poison which kills so quickly from the fang of a cobra and the ordinary white of an egg can hardly be distinguished by the chemist. He finds them both to be albumen.' "'Why, then, should one kill and the other be harmless?' I asked. "'Simply the minute "something else" which is contained in the snake poison and which is held in solution by the albumen.' "'Have you any other proof of the power of this Elixir?' I inquired. "'My dear sir, I trust you do not question the truth of my statement regarding my own age.' "He frowned slightly, and those wonderful eyes of his glanced like lightning towards the two huge attendants standing in plain sight in the hallway. "'Not at all,' I hastened to assure him. 'It all seems so wonderful to me, you must excuse my apparent incredulity.' "'The most natural thing in the world,' smiled Sing with grave courtesy, 'but I will let your own eyes banish any doubt you may have as to the wonderful properties of this strange powder. "'Ashmed,' he called, 'ask my son to come here a moment if he will be so good.' "The attendant who had spoken to me when I entered immediately disappeared, and in a moment a back door opened and the bent figure of a very old man entered the room and spoke to Sing in a weak voice. The language was evidently Hindustani, but I caught a word here and there which sounded familiar. Sing spoke to him sharply, and turning to me said, 'This is my son; he is nearly eighty years old, but refuses to take the powder on account of his religious principles--he belongs to the sect who believes that to die is better than to live, that his spirit will become incarnate in another body, and in his next life he will be at least a Kobtchie.' "My eyes must have betrayed my incredulity. "'You do not doubt that he is my son?' sweetly asked Mr. Sing. "'Certainly not,' I answered. "'I trust, then, that I shall have the pleasure of furnishing you with some of the wonderful powder? There is not very much of it left, but luckily it requires a very small dose. I have enough probably to supply one hundred men to insure them existence for one hundred and fifty years. When that is gone the supply can never be replenished.' "He sighed.