Gun cotton was brought into public notice by some experiments by its inventor, Professor Schönbein, of Basel, before the chairman of the East India Company, and a number of scientists. Professor Brande had previously lectured upon it, at the Royal Institution, on 15 Jan., when he stated that, about fifteen years before, Braconnot had ascertained that sawdust, wood shavings, starch, linen and cotton fabrics, when treated with concentrated nitric acid, produced a gelatinous substance, which coagulated into a white mass, on the addition of water; this substance, which he called “xyloidine,” was highly inflammable. Schönbein, however, made his explosive from purified cotton, steeped in a mixture of equal parts of nitric and sulphuric acids, which when carefully washed, and dried, kept its appearance of cotton wool. In the _Times_ of 4 Nov., is a notice of Gun sawdust (a powder now much used), made by Mr. George Turner of Leeds. Whilst on the subject of Chemicals, I may as well mention, what was much talked of at the time—the discovery of sulphuric ether, when inhaled, being an anæsthetic. Previous to this, Nitrous Oxide, or, as it was called, “Laughing Gas,” somewhat inadequately performed the same function. This latter was discovered by Dr. Priestley, in 1776, and its use, as an anæsthetic, recommended by Sir H. Davey in 1880, was put into practice by Mr. Wells, in America, to lessen the pain in extracting teeth in 1844. The first notice of the inhalation of sulphuric ether that I know of, is in No. XLV. of the _British and Foreign Medical Review_, which says: “Just as our last proof was passing through our hands, we received from our medical friends in Boston, the account of a matter so interesting to surgeons, and, indeed to everyone, that we take the opportunity of introducing it here. We know nothing more of this new method of eschewing pain than what is contained in the following extracts from two private letters, kindly written to us by our excellent friends Dr. Ware and Dr. Warren, of Boston—both men of the highest eminence in their profession in America—and, we may truly say, in Europe also. It is impossible, however, not to regard the discovery as one of the very highest importance, not in the practice of operative surgery only, but, also, as Dr. Ware suggests, in practical medicine. We trust our friends will forgive us for putting into print their private communications. The importance of the subject, and the necessity of authenticating the statements, are our excuses. The authors of the discovery are Dr. C. T. Jackson and Dr. Morton.