[F] Fischer adopts a chemical basis in his classification. His two main subdivisions are (1) inorganic and (2) organic poisons. The sub-divisions of the inorganic poisons are (_a_) non-metallic—chlorine, calcium chloride, hydrochloric acid, potassium chlorate, hydrofluoric acid, carbonic oxide, phosgene, carbon dioxide, cyanogen compounds, ammonia, nitrous fumes, phosphorus, phosphoretted hydrogen, arsenic compounds, antimony compounds, sulphur dioxide, sulphuric acid, sulphuretted hydrogen, carbon bisulphide, chloride of sulphur; and (_b_) metallic—chromic acid and chromates, manganese dioxide, sulphate of nickel, mercury and lead. The sub-divisions of (2) the organic substances are into (_a_) the unsaturated carbon compounds—benzene, petroleum, methyl-, ethyl-, amyl-, and allyl-alcohol, oxalic acid, formal- and acetaldehyde, acrolein, acetone, methyl-bromide and iodide, nitro-glycerin, dimethyl-sulphate and amyl acetate, and (_b_) the aromatic series benzene, nitro-, chloro-nitro-, dinitro-, chloro-dinitro-benzene, phenol, picric acid, phenyl-hydrazine, aniline, and certain aniline colours, para-nitraniline, pyridine, naphthalene, nitro-naphthalene, naphthlyamine, naphthol, benzidine, acridine, turpentine, and nicotine. [G] A Prussian Ministerial Decree, dated March 31, 1892, deals with the preparation of nitrate of mercury. [H] In Great Britain and Ireland the White Phosphorus Matches Prohibition Act became operative from January 1, 1910. In the United States of America a Prohibition Act became operative on July 1, 1913. [I] Reprinted by permission of the Controller of H.M. Stationery Office. [J] _Use of Oxygen Cylinder._—Open the valve gradually by tapping the lever key (which must first be extended to its full length) with the wrist, until the oxygen flows in a gentle stream from the mouthpiece into the patient’s mouth. The lips should not be closed round the mouthpiece. The nostrils should be closed during breathing in, and opened during breathing out. If the teeth are set, close the lips and one nostril. Let the conical end of the mouthpiece slightly enter the other nostril during breathing in, and remove it for breathing out. [K] The suggested regulations made after his inquiry (see p. 149) by Dr. Copeman are: 1. Ferro-silicon should not be sent out from the works immediately after manufacture, but after being broken up into pieces of the size in which it is usually sold, should be stored under cover, but exposed to the air as completely as possible, for at least a month before being despatched from the works. 2. Manufacturers should be required to mark in bold letters each barrel or other parcel of ferro-silicon with the name and percentage grade (certified by chemical analysis) of the material; the name of the works where it is produced; the date of manufacture; and date of despatch.