"Ah," he cried vehemently, "that accursed word again! Carbonic acid has undone me, clearly. Yes, if you will have it so, that seems to be what they call it in this extraordinary century; but fixed air was the name we used to give it in our time, and fixed air is what I must call it, of course, in telling you my story. Well, I was deeply interested in this curious question, and also in some of the results which I obtained from working with fixed air in combination with a substance I had produced from the essential oil of a weed known to us in England as lady's mantle, but which the learned Mr. Carl Linnaeus describes in his system as _Alchemilla vulgaris_. From that weed I obtained an oil which I combined with a certain decoction of fixed air into a remarkable compound; and to this compound, from its singular properties, I proposed to give the name of Pausodyne. For some years I was almost wholly engaged in investigating the conduct of this remarkable agent; and lest I should weary you by entering into too much detail, I may as well say at once that it possessed the singular power of entirely suspending animation in men or animals for several hours together. It is a highly volatile oil, like ammonia in smell, but much thicker in gravity; and when held to the nose of an animal, it causes immediate stoppage of the heart's action, making the body seem quite dead for long periods at a time. But the moment a mixture of the pausodyne with oil of vitriol and gum resin is presented to the nostrils, the animal instantaneously revives exactly as before, showing no evil effects whatsoever from its temporary simulation of death. To the reviving mixture I have given the appropriate name of Anegeiric. "Of course you will instantly see the valuable medical applications which may be made of such an agent. I used it at first for experimenting upon the amputation of limbs and other surgical operations. It succeeded admirably. I found that a dog under the influence of pausodyne suffered his leg, which had been broken in a street accident, to be set and spliced without the slightest symptom of feeling or discomfort. A cat, shot with a pistol by a cruel boy, had the bullet extracted without moving a muscle. My assistant, having allowed his little finger to mortify from neglect of a burn, permitted me to try the effect of my discovery upon himself; and I removed the injured joints while he remained in a state of complete insensibility, so that he could hardly believe afterwards in the actual truth of their removal. I felt certain that I had invented a medical process of the very highest and greatest utility. "All this took place in or before the year 1781. How long ago that may be according to your modern reckoning I cannot say; but to me it seems hardly more than a few months since. Perhaps you would not mind telling me the date of the current year. I have never been able to ascertain it."