Of the science of poisons, however, he knew absolutely nothing, and as the waiter seemed quite unable to find anything in the library butRuff's Guide and Bailey's Magazine, he examined the book-shelves himself, and finally came across a handsomely-bound edition of the Pharmacopoeia, and a copy of Erskine's Toxicology, edited by Sir Mathew Reid, the President of the Royal College of Physicians, and one of the oldest members of the Buckingham, having been elected in mistake for somebody else; a contretemps that so enraged the Committee, that when the real man came up they black-balled him unanimously. Lord Arthur was a good deal puzzled at the technical terms used in both books, and had begun to regret that he had not paid more attention to his classics at Oxford,when in the second volume of Erskine, he found a very interesting and complete account of the properties of aconitine, written in fairly clear English. It seemed to him to be exactly the poison he wanted. It was swift—indeed, almost immediate, in its effect—perfectly painless, and when taken in the form of a gelatine capsule, the mode recommended by Sir Mathew, not by any means unpalatable. He accordingly made a note, upon his shirt-cuff, of the amount necessary for a fatal dose, put the books back in their places, and strolled up St. James's Street, to Pestle and Humbey's,the great chemists. Mr. Pestle, who always attended personally on the aristocracy, was a good deal surprised at the order, and in a very deferential manner murmured something about a medical certificate being necessary. However, as soon as Lord Arthur explained to him that it was for a large Norwegian mastiff that he was obliged to get rid of, as it showed signs of incipient rabies, and had already bitten the coachman twice in the calf of the leg, he expressed himself as being perfectly satisfied, complimented Lord Arthur on his wonderful knowledge of Toxicology, and had the prescription made up immediately.