Remembering, then, that legislation on the sale of poisons is utterly unable to _prevent_ poisoning, that all it can do is to make the means a little difficult, and the detection more easy, how can we approve the proposal at this moment made, to tack on a few, very tentative clauses to an unsuccessful Act, and four more names to a very defective schedule? Why insert chloride of antimony, and omit nitrate of silver, sulphate of copper, and chloride of tin? The essence of a “poison” is _quantity_; and no Act which does not specify the maximum quantity that may be sold, can be effective. Beyond this, why should it be more criminal to _sell_ a dangerous substance to a poisoner than to _give_ it to him, or by culpable negligence to allow him to take possession of it? If such neglect were made punishable, if people who left arsenic, &c., about in cupboards without precaution, had to suffer for the consequences, we should hear less of such “accidents.” I am deeply indebted to Dr. Bernays, Professor of Chemistry at St. Thomas’s Hospital, for kind advice and facilities of consultation and experiment; to Doctors Harley, Ord, Acland, and to my namesake, Mr. Charles Stewart, F.L.S., for many valuable suggestions; and especially to Mr. E. G. Clayton, F.C.S., who contributed the main part of the chapter on Aconitia, and helped me materially in other portions of the chemical notes. The main authorities drawn upon have been:— Taylor’s Medical Jurisprudence, 1873. Taylor on Poisons. Woodman and Tidy’s Handy-Book of Forensic Medicine and Toxicology, 1877. Blyth’s Manual of Practical Chemistry, 1879. Guy and Ferrier’s Forensic Medicine, 1881. Allen’s Commercial Organic Analysis, 1879. Royle’s Materia Medica, edited by Dr. J. Harley, 1876. Christison on Poisons, 1829. Fresenius’ Qual. and Quant. Analysis. Watt’s Dictionary of Chemistry. Chemical Society’s Journal. Chemical News, Lancet, &c. Farquharson’s Therapeutics. Mohr’s Toxicologie, trans. by Gautier, 1876. Casper’s Handbook of Forensic Medicine, trans. by Balfour, 1861-5. Beilstein’s Organische Chemie, 1882. Year Book of Pharmacy. British and other Pharmacopœias. Squire’s Companion. In conclusion, it has been obviously impossible in the limited space to explain elementary facts or principles. These may be ascertained from any of the standard textbooks. C. G. S. CONTENTS. PAGE PREFACES v ADDENDA: DIFFERENCES BETWEEN STRYCHNIA AND MORPHIA xv ” PROCESS FOR OBTAINING PURE CHLORINE xvi CHAPTER I. CHEMICAL INTRODUCTION.